FAQ's Expert Guide to: Bass Management, featuring acoustics expert, Anthony Grimani

Summary

Highlights

• Anthony Grimani emphasizes that bass is misunderstood and is critical for perceived quality in sound systems. 🎧
• Discusses 'bass management' as an enduring challenge in audio technology, needing thoughtful design and placement. 🎛️
• Highlights the importance of subwoofer placement and room acoustics to prevent standing waves and achieve clear bass. 📡
• Explores the use of modern tools and strategies for measuring and adjusting bass frequencies in different room environments. 🛠️
• Grimani outlines steps for bass management, including subwoofer placement, acoustic treatments, and room design adjustments. 🏗️

Key Takeaways

• Bass is a crucial element in audio quality, often misunderstood, but it’s not just about loudness – it requires careful management. 🎵
• Subwoofer placement is vital in sound management; multiple smaller subwoofers often outperform a single large one. 🔊
• Room acoustics, including dimensions and materials, significantly affect bass quality, and strategic design can eliminate standing waves. 🏠
• Using tools like Room EQ Wizard and proper measurement techniques helps in optimizing bass performance in any room. 🚀
• The session provides insights into enhancing bass, not only for solitary listening but also in shared environments like home theaters. 🎬

Overview

Chapters

• 00:00 - 01:00: Introduction The chapter titled "Introduction" focuses on the significance of bass in music, using a light-hearted reference to caffeine as a metaphor for the energy and liveliness that bass brings to a piece. The discussion addresses a common misunderstanding about bass, suggesting that its importance is often underestimated. The transcript hints at statistical evidence supporting the idea that bass significantly influences the perception of music quality.
• 01:00 - 05:00: Importance of Bass Management The chapter titled 'Importance of Bass Management' begins with reflecting on the evolution of audio systems since the mid-90s, emphasizing the growing complexity of managing bass. During this period, the term 'bass management' was coined due to the challenges in ensuring optimal sound capability in different room settings. Bass management remains a significant issue, considered a complex puzzle that audio engineers continue to solve. The significance of bass is highlighted by the audience's positive reactions during audio demonstrations, illustrating its critical role in enhancing audio experiences.
• 05:00 - 10:00: Challenges with Bass in Rooms The chapter discusses the challenges of achieving good bass sound in rooms, observing that when bass quality improves, people naturally respond positively, sometimes with pronounced enthusiasm. Some individuals even go so far as to tattoo a bass clef on their arm, indicating a deep commitment to bass music. The chapter references Sean Olive, a renowned audio engineer, stating that approximately 35% of perceived sound quality is derived from frequencies ranging from 20-200 Hz.
• 10:00 - 20:00: Subwoofer Placement and Myths The chapter discusses the importance of improving bass frequencies in audio systems, particularly highlighting subwoofer placement. It emphasizes that low bass plays a critical role in the perception of sound quality, even though it covers only a small range of the audible spectrum. The text underscores the tactile nature of very low frequencies, suggesting that they are felt physically as much as heard, demonstrating their impact on listener experience.
• 20:00 - 30:00: Understanding Standing Waves The chapter titled 'Understanding Standing Waves' discusses the immersive experience of sound systems and the difficulty in achieving the right vibration management. It highlights the importance of low frequencies in music and film, especially in residential spaces ranging from 200 to about 800 square feet.
• 30:00 - 40:00: In-Room Measurements and Tools The chapter discusses the challenges posed by standing waves in rooms of 70 or 80 square meters, which can create significant acoustical issues regardless of whether a person is standing or sitting. The importance of headroom for playing high sound pressure levels is highlighted, and while there are solutions available for these acoustical challenges, they are often overlooked.
• 40:00 - 50:00: Solutions for Better Bass The chapter discusses the longstanding ignorance in various environments towards improving bass sound quality. Despite legends and myths surrounding bass, the speaker focuses on tangible results and addressing issues with practical solutions.
• 50:00 - 60:00: Subwoofer Configuration Strategies The chapter discusses common misconceptions about subwoofer placement, especially in consumer forums. It questions the belief that bass is omnidirectional, and therefore, placement does not matter. The chapter addresses whether subwoofers should be positioned up front with the speakers. Legends about subwoofer placement are explored, such as the need for them to be up front with speakers to ensure sound waves are aligned.
• 60:00 - 70:00: Manual Optimization Techniques This chapter delves into manual optimization techniques for sound systems, specifically addressing the myth that bass is non-directional and the placement of subwoofers. An example is given of a typical room setup for a 5.1 channel system, and the chapter explores whether arbitrary placement of subwoofers is advisable. It suggests that while common belief might say it doesn't matter where a subwoofer is placed, the chapter aims to examine the actual effects of subwoofer location.
• 70:00 - 80:00: Seating and Room Design Considerations The chapter titled 'Seating and Room Design Considerations' explores the impact of subwoofer placement on acoustic performance within a room. The focus is on the frequency range from 20 to 200 Hertz. The chapter details a series of measurements conducted by moving a subwoofer to various locations and measuring the outcomes. The subwoofer used was an older model loaned by David Nelson from Triad, chosen for its quality. Initial results and observations include its impulse response measurements.
• 80:00 - 90:00: Understanding Room Acoustics The chapter "Understanding Room Acoustics" discusses the process of measuring acoustics in a room. It emphasizes taking accurate measurements by positioning the microphone correctly, whether near the speaker cone or further out in the room. The text references the capabilities of sound equipment in isolation from the room's influence. Craig Todd raises a question about measurement techniques, suggesting the use of Room EQ Wizard with impulse response or pseudo random pink noise for accurate readings, ensuring a resolution of at least 12th or 24th octave.
• 90:00 - 100:00: Damping and Bass Absorption The chapter "Damping and Bass Absorption" discusses the use of impulse response schemes to gather data beyond just amplitude response. It mentions that octave doesn't significantly impact this process. The narrator thanks Craig for a question related to the topic. The results of nearfield measurements are highlighted, mentioning the use of the Room EQ Wizard (REW) with impulse response schemes, which requires some learning through tutorials. The chapter emphasizes the effectiveness of a particular subwoofer, noted for its strong beginning at 20 Hz.
• 100:00 - 110:00: Calculations and Real-World Examples The chapter 'Calculations and Real-World Examples' discusses the performance of a subwoofer when placed in different parts of a room. It uses real-world measurements to illustrate how the subwoofer's response varies depending on its location, such as near where a left speaker would typically be placed. The response is measured in decibels (dB) and remains consistent up to 200 Hz. A picture of the room setup is provided to support the findings, emphasizing that these are not theoretical calculations but based on actual measurements.
• 110:00 - 118:00: Summary and Final Thoughts The room being discussed is relatively small, measuring approximately 5 meters by 4 meters by 2.75 meters (equivalent to 16 by 13 by 9 feet). The transcript highlights the effect of this room size on the subwoofer's performance, noting that the conditions such as microphone placement, cables, and settings remained consistent, providing insight into the acoustics impact in such confined spaces.

FAQ's Expert Guide to: Bass Management, featuring acoustics expert, Anthony Grimani Transcription

• 00:00 - 00:30 [Music] that's right that's right the cappuccino is kicking in and it's all about that base that's that's excellent let's jump into this you guys it is all about that base obviously it's not all about it but it is a big piece to it and it's something that's frankly a little misunderstood sometimes so you're right Brett Bas is important not just because the song says so interestingly enough there's some statistics that show that the perception of quality of B dominates
• 00:30 - 01:00 many many other things let me let me go to a share screen over here you know you go back to the mid 90s and you go wow Bas is getting is getting complicated and I got very interested in like how do we manage this how do we make sure that any sound system that's put into a room has the the best capability and base and coined the termbase management back then and it's still an issue it's still challenging it's a complex puzzle is what I like to say now base matters audiences love it they look at the reaction from people on a demo that
• 01:00 - 01:30 doesn't have good base and then you know if you could magically switch it on you you'd see everybody Smiles go up everybody just you know go againsts into it's fun some people love it so much that they actually tattoo it on their arm that's a Bas cleft I mean that's more commitment than I'm really willing to do it to you know tattoo it on there but a gentleman by the name of Shan Olive who is a very very well-known audio engineer in our in our in our midst has coined that about 35% of sens of quality comes from the range from 20
• 01:30 - 02:00 Hertz up to about 60 70 Herz that's only two octaves out of the 10 that you hear and that dominates your sense of this sounds good and so if you want return on investment if you're on this webinar because you're a salesperson and you want to get great return on investment on what you're selling to people improve the base and by improve the base we're going to talk about that what does that mean so low basis tactile there's a frequency below which it start stops being heard as tones and it starts to be felt and that's where people go oh how
• 02:00 - 02:30 how cool I I feel like I'm being reached out to by the sound system and it's immersing me in because I'm vibrating it's very cool but it's hard to do it's hard to get right you got to manage it and what do I mean by managing we're going to talk about that so on the agenda for today is low frequencies are important for music and for film and they are challenging in the spaces in which we work in the residential space you know rooms between 200 square F feet that's 20 MERS up to about 7 or 800 ft
• 02:30 - 03:00 that's 70 or 80 Square met the way the waves propagate and bounce around creates some serious challenges because of what's called standing waves and the joke I say is standing waves are going to be in the room whether you stand or sit by the way you know I've said people say well like what if I sit down do I hear them it's like well depends on the standing wave there are Headroom issues you need to be able to play high sound pressure levels in based for a tall workout and there's a lot of solutions but they're they're often ignored I know I've talking about this like I said for
• 03:00 - 03:30 30 years there's other scientists that have been talking about it for 20 25 years and I keep going into these environments where really ultimately no attention was paid to the issues and that's too bad but that's why we're here there's there's a lot of Legends out there about what base is and what is not I hear all kinds of oh blah blah blah this is what happens and some of it it's like well listen to the result is this are you good with this no okay let's talk about how to solve it you know one
• 03:30 - 04:00 of the things that I see a lot of times Anthony and especially in the consumer forums you know subwoofers just sitting up front just to sit up front right I've even seen you know multiple subwoofers sitting up front does that always work is base omnidirectional you know you you hear a lot of stuff about where to position speakers but what about positioning subwoofers one of the Legends like you said is BAS is non-directional so you can put the subwoofer wherever you want another Legend is no B the subwoofers need to be up front with the speaker so that the sound you know goes with the waves hit
• 04:00 - 04:30 you and they percuss you well that's not exactly how Sound Works so Legend Number One Bas is non-directional so you can put the subwoofer anywhere really is that true so here's an example of a room set up for just barely 5.1 channel three three fronts side left side right and a subwoofer stuck you know on the right wall by where it could fit that's an example so is that okay maybe yes maybe no so let's look at the effects of subw warer location I'm going to show you
• 04:30 - 05:00 some measurements done in a room where I I move the subwoofer around measure the result move the subwoofer to a different place measure the result and let's look at what happens in the range from 20 to 200 Hertz that's the range that we're here to discuss so first off I start with a a good subwoofer this particular one is from several years ago that David Nelson from Triad loan me for an evaluation it's a it's a very good subwoofer and here's its impulse response it was measured this is a
• 05:00 - 05:30 measurement in the near field is the actual picture uh take a good measurement microphone stick it in the cone put it outside and here is what the subw Warfare can do without any room around it right so this is what this this is what the unit can put out in the room Craig Todd just asked like how do I measure this I happen to measure this with roomie Q wizard using the impulse response scheme you could also measure it using their pseudo random pink noise scheme uh make sure you go to to at least 12th octave resolution or 24th
• 05:30 - 06:00 octave doesn't really matter there using the impulse response scheme gives you other data than just the amplitude response so that's a good thing to do thank you Craig for that question and so this I'm measuring nearfield the following the results that are coming up we also measured using room EQ wizard Rew using the impulse response scheme that works takes a little bit of learning go through the tutorials so this is a good subw Warfare what I mean by good is it starts well at 20 at 20
• 06:00 - 06:30 htz and the response is within a DB or two all the way up to 200 HZ okay good subwoofer now let's take that same subwoofer put it into the room at a location near where the left speaker would be or you would get the same thing if you had a full range left speaker let's take a look at the result first of all here's a picture of said room this is not theoretical these are actual real measurements there's that same microphone there's that same subwoofer sitting at where you would normally plop left speaker and the this particular
• 06:30 - 07:00 room I'm using is 5 5 m x 4 by 2.75 more or less which is about 16 by 13 by9 not a very big room now this is the measurement you get at this microphone location that is more or less where you would want to put a seat from that subwoofer at the left location this is the this is what the room has done to the subwoofer same everything else same cables same Dolly same wire everything else is the same we went from outside
• 07:00 - 07:30 the room with the with the microphone in the cone measuring just the subwoofer to put the subwoofer in the room and measure it there are 38 DB of error between this peak and that null in this room that's what the room just did to this poor subwoofer that's bad remember this is what the near field was this is what the subwoofer is putting into the room this is what the subwofer plus the room did that's a problem yeah right what
• 07:30 - 08:00 what this means is at this particular location you're not going to hear any 52 Hertz whatever is playing in that region is ducked down there's going to be a peak somewhere around 38 Hertz and then it's going to go up and down and up and down and up and down guess what's right around 52 Hertz any drummers in the room a nice big kick drum rock and roll Kick Drum typically a 21 22 in 24 in Kick Drum is right around that so if you're listening to solid rock and roll
• 08:00 - 08:30 rather than get that thump you get from All About That Base you're just hearing the Mallet there's there's no good base so fine so that's that one location uh let's move the subw Warfare to a different location if you say you can put a subwoofer anywhere let's see what happens if we put it somewhere else so there's a picture there's a picture now subers moveed to the center location the The Legend says you can put it anywhere well here's the result we've got now a
• 08:30 - 09:00 less bad error it's 28 DB instead of 38 DB but it's equally bad between this peak and this dip that dip has moved slightly to a different frequency still not good so let's see if we move it to the right location here's a result of that response at that right location so now the error is a whole lot less bad it's good it's less batter it's still not great it's 20 DB difference between this peak and this dip notice that every everything has changed in the frequency ranges here we
• 09:00 - 09:30 now have this PE this peak was there before but now there's a dip of 30 it's all it's all different if I overlay those three these are just three locations just I I just chose those as what you would do if you had either had a full range speaker or put a subwoofer right by that speaker or like some people think you put a subwoofer with each speaker this is this is the difference notice interestingly enough it's all bad interestingly enough the room is symmetrical it's a break angular room and the left and right don't look
• 09:30 - 10:00 anything like each other right that excuse me this is the right the right is in red the left is in blue they look totally different yeah now we could just continue just for fun and look at what would happen at the side left and side right location so if you put the subwoofers on the sidewall this is what they look like there are still errors of 20 DB still bad you know it's still not working for us you you got to
• 10:00 - 10:30 have decent base or else it or else you just don't enjoy the sound uh do we agree we have a problem so this is an example of one room if we had six hours I could show you tons and tons and tons of data on many many many many many rooms I've been in and out in the last 30 years I've measured about a thousand different rooms residential size spaces that all have worse or better problems than this but we have a problem and what I found over over the years is you got
• 10:30 - 11:00 to manage it and the management is actually a six-step process you can do just one of the six steps and it makes things better but you really need to do six different things to get to a point where that base is tight and clean and even and doesn't change too much from seat to seat and you know it's just it's confusing I I find it interesting that when we look at that left and the right speaker you would assume hey they're on opposite sides if it's a relatively symmetrical room wouldn't they at least be off the same amount and and they're not I'm really a fan of trying to get to
• 11:00 - 11:30 the bottom line of this so um I am going to share my screen again it's the the root caus is generally it's not the only thing but is standing wave resonances that's what that's what messes us up in in in these rooms so what does that look like when you're getting down into the base region and the waves are about the same size as the room or the same size as the room where here I'm showing a representation of wave that's zigzagging around I'm just trying to show that it's
• 11:30 - 12:00 the peak dep range of a sound pressure wave just fits in the room but also when half of a wave fits in a room a one and a half wave when there's like integrals of that you got a problem standing waves happen when room Dimension is equal to sound wavelength or when you're looking at the length width and height the three room dimensions are equal to that or 0.5 1.5 2 2 and a half three times the wavelength and that causes a resonance because the wave right at that point is happy to bounce back and forth and stay
• 12:00 - 12:30 just like the string on a guitar when you pluck it it's just happy to ring at one note and that means there's some frequencies that are louder than others so you end up with an uneven frequency response you end up with poor Bas impact like I showed you in the result of that you're missing 52 Hertz you can't get good rock and roll Kick Drum if you don't have that frequency also you get a different base at other seats I have a ton more data on this room showing the results at different locations so not only as we move subwoofer locations
• 12:30 - 13:00 around does the base result change but given one subwoofer location you can move around in the room and the base result changes so different bases at at every seat as a bad news and usually the biggest problems in residential spaces are between 30 and 150 Hertz at least where construction is made out of sheet rock on studs or gypson board on studs because below that they start to absorb or transmit base so how do those residences happen so I've been kind of
• 13:00 - 13:30 scratching my head for years for like how to represent this I always like to graphically try to show what happens let's look at this imagine this is a room from front to back and you're sending a wave in a room that is at the first resonance in which the full wave is twice as long as the room imagine you have a room in which the whole back is open you got giant patio doors if there's no wall there's no reflection the wave just goes right out now take that same room close the big patio doors in the back and the sound bounce bounces back right so instead of of going out it
• 13:30 - 14:00 just reflects back so who cares is that what causes it well not so simple really sound pressure that you're hearing is a change or sound that you're hearing is a change of pressure over time right if you just put pressure in your ear you feel the pressure but there's no sound where you hear sound is when the pressure goes from rest to positive pressure back to negative pressure back to rest and back and forth and back and forth incidentally it mainly fires on the outgoing pressure not on the in one
• 14:00 - 14:30 the the auditory system is a halfwave rectifier if you want to think of it that way so what I'm going to represent now on the left over here is really the sound propagated by maybe a subwoofer which is going from high pressure to low pressure to high pressure and at every pressure point it's propagating through the room so check this out this is later in time later in time later in time later in time just focus on the left side of the of the room so this is pressure going up and down which is the woer pushing air coming back to rest
• 14:30 - 15:00 pulling air pushing air rest being right in the middle okay so this is pressure up neutral down now look at how it propagates through the room this one at high pressure goes through and bounces back this one cone a little bit less far propagates through the room and comes back propagates through the room and comes back propagates through the room Etc if you go to the opposite side of the room you're hearing the same sound it actually happens to be out of polarity we'll get back to that later
• 15:00 - 15:30 but you're hearing the pressure going up and down or your pressure is going up and down which means you're hearing it your brain's going hey something just happened at my ear what happens if you're in the middle of the room you look at this there's been no change of pressure over time change of pressure over time no change of pressure over time change of pressure this is an effect of the standing wave which is on either side of the room you've got sound and in the middle of the room in this case when the wave is twice as long as the room there's no sound zero or 40 DB
• 15:30 - 16:00 down which is 1% of where you started if you take the same wave and you put it in a room that's different or you change the wave to where that point that originally was at the boundary is now at a different place it bounces back it doesn't overlap there are no standing waves so we can represent the standing wave or the region of sound from standing waves this way this is a this is I'm going to keep talking about this first one this What's called the first
• 16:00 - 16:30 harmonic which the wave is twice as long as the room it can represent that the resulting sound level looks like this this is not a wave this is just a map of it's loud it's loud and right here it's quiet okay this kind of gwing look just represents that right here it's quiet here it's loud here it's loud this is the actual wave that you're sending into the room so I only talked about the first residence the one in which the wave is twice as long as a room the second one which is when the wave
• 16:30 - 17:00 entirely fits in the room you end up with a null at one4 and a null at 3/4 okay so everything I just talked about before where there's a null in the middle you double the frequency and now in the middle it's nice and loud at the wall on one side and the other it's nice and loud but one quarter of the way into the room and 3/4 of way into the room there's no sound or there's a reduction of sound level at the third harmonic in which you can fit one and a half waves in the room there's a null at six up Peak at 2 six which is a third a null at
• 17:00 - 17:30 3 six which is also 1/2 a a Peak at 4 six which is 2/3 and then an all at 56 and guess what happens in the fourth harmonic when you can actually fit two waves in there there's a series at the eights one eights two eights 38s Etc so this is a really simple way to look at how these residences happen sure but but it's telling me I can't get a I can't get a seat anywhere right because I can't put it in the middle I can't put it in the quarters I can't put it in the thirds and I can't put it in the uh in
• 17:30 - 18:00 the eights ah grasshopper there actually we're going to talk later about seats there is a place where you can kind of snake your way around there I I'll give you I'll give you a hint somewhere right around here you're neither at the nulls or peaks of that neither paks of that you can actually cheat it and that's a really important thing one of those steps in your toolkit for for getting around standing waves just don't sit at a place where you hit so don't sit in the middle of the room don't sit at a quarter that you know that's what works here's another representation of the
• 18:00 - 18:30 same thing I'm I'm not saying anything new I'm just showing it differently this is a room SE seen from above with a really nice loudspeaker that consists of a red box with a horn in front of it good looking speaker nice huh hey Brett you and I should go in business to making those so and what I'm representing over here is is the the second harmonic standing wave just seen from the top the the What's called the axial length standing wave it's loud here it's loud here it's loud here it's quiet here it's quiet here now Murphy's first law of
• 18:30 - 19:00 Acoustics says that wherever you want to put the couch it's going to be right at a null of a second harmonic of course and if you move the couch the null moves with you no it it happens because this is three quarters of the way back in the room a lot of people you know naturally want to sit somewhere between 2/3 and 3/4 back in the room and that's right where there's no no base at the second harmonic now another effect of the standing waves so here this effect is just that there's errors in frequency response there's frequency with
• 19:00 - 19:30 frequencies where there's nulls and Peaks another effect is that there's also resonances over this frequency is a resonance at this particular frequency the sound is going to hang and this is an example of a room Decay and what's called a waterfall plot done years ago I should redo this but this is showing that there's a long Decay Series right around here the sound at other frequencies this is showing your progression over time this this is actually using te man that push us back a few years this is 12 milliseconds
• 19:30 - 20:00 after the beginning of time which is 12 the time it took for the sound to travel 12 feet to the microphone and this is 800 milliseconds which is close to the time it takes for the sound to fully die out and you look down here at lower frequencies the sound passes the microphone a few times and then dies out kind of as a as an even falloff and in this particular room at 52 Herz the the sound is just hanging it's louder and it hangs a long time so some notes are totally on other notes just hang a long
• 20:00 - 20:30 time so rather than get nice tight Punchy even bass you end up with some notes that just go and other ones that are not there at all that's bad base can't do that so that's that's how this you know that's basically how this happens in these rooms so the the main effects of audibility or standing wave are errors and frequency response and then the sense of resonance where some notes are just hanging and rather than sound even it's just kind of mushy I was joking about how I had this old plot well I have a newer plot too this is um
• 20:30 - 21:00 interestingly enough this is that same room I was bringing up earlier what we call the Blue Room here and that's the first subwoofer one at Mike one and it shows a resonance at at 72 Hertz so same thing here when you look at a waterfall plot these all come from room EQ wizard so I want to I want to give them a plug so the guys at roomi QQ wizard designed an absolutely Stellar unbelievably good and Alice's tool it takes some time to
• 21:00 - 21:30 learn it there's great tutorials it's a free download but please send them 50 bucks or 100 bucks for the amazing work that they've done to program this it's better than anything else I bought for for tens of thousands of dollars before it's unbelievable one of the things you can do is you can do what's called an Impulse response sweep and then tell it show me how all of the sounds decay all the frequencies Decay over time and in this particular room when you look at the range from 6 or 700 Hertz on up to 10 K you can see that that waterfall you
• 21:30 - 22:00 know how those frequencies Decay is really even which which is a sign of good mids and highs and you can see that at that s if you use that single subwoofer at that location you see how this Ridge just hangs forever here while everything else is gone by about 300 milliseconds this takes a good 800 milliseconds before it's gone that means it's hanging for a long time so that's an example of tools you can get today that can tell you all that for free you need you
• 22:00 - 22:30 do need to get a microphone for 70 or 80 bucks come on what's that so Solutions there are solutions good news is you're not stuck with it you don't have to live with it and what I'm going to do on on this series here is give you Solutions not necessarily in order of design but in order of like okay I have my room what can I do I don't want to rebuild a room I have my room what can I do well one of the things you can do is is pick the right subwoofer or place it at the right location or do something so that
• 22:30 - 23:00 you find the place that that is least bad you you may remember from all of my my measurements there was one that was horrible at 38 DB error there was one that was less bad at 20 DB is there some if I kept moving that subwoofer around is there a location for a single seat listener environment where where it's within plus and minus 5 DB that's not bad there is you can of course it's going to be be right in the middle of a door it's going to be right totally
• 23:00 - 23:30 impractical but there is a location or there's other things you can do so first thing what I'm going to talk about here which is either free because you just move the subwoofer around or maybe more expensive because you get to buy more subwoofers what what can you do with placing subwoofers so fir first of all in choosing your sub offers let's let's let's imagine you've got a room it may have a problem may not have a problem you got to pick subwoofers you got to figure out what's the bandwidth you're trying to get out of the subwoofer and how do you want to play some people out
• 23:30 - 24:00 there get subwoofers that are way too big for the room they they they put you know four 24in subwoofers in a room that's only 300 sare ft and that's like ridiculous yeah you got a lot of Base but it's pointless and other people put these little bitty subwoofers that can barely get up to 95 DB you need to be able to play 110 DB in room we'll talk about that later so you got to you got to pick the right subwoofers based on the dimensions and character of your room so ideally you want to play to 110 Maybe 115 DB in
• 24:00 - 24:30 room if you're going to use quote unquote full range loudspeakers and say I don't need subwoofers beware your speakers are going to end up being really big there are people who make speakers with a 15-inch warer in it with plenty of of power to get there but it takes a lot of con or you really do need a subwoofer and if you're going to do a subwoofer multiple subwoofers I would prefer to have two smaller subers than one big one better yet four maybe even smaller subw offers rather than one that
• 24:30 - 25:00 you can hide away in a room there's a guy called Todd Welty and his buddy Al no this is scientific annotation for Ed Al and others that have written several Publications please read them look up his name at the time he was doing a lot of This research he was working for Harmon Internationals research group but very smart guy I I call him the doctor of of subwoofer he knows more about Bas and base propagation in room than just about anybody else in the world um so my my first like really bit picture is if
• 25:00 - 25:30 you just retain one thing from today is it is better to have multiple subwoofers preferably for all playing the same sound maybe adjusted differently slightly but they're receiving the same signal in mono not stereo not left and right not front and back but in in these smaller rooms in mono so Todd wrote this paper back in 2003 so this is 20y old information that did all this analysis and measurement on the paper is called the subers how how many is enough or
• 25:30 - 26:00 something like that it was presented at the audio engineering Society I think it was in Munich Amsterdam I forget somewhere in Europe I happen to be there and sat through the paper it's like holy moly he's got it did all all of this math and Analysis and measurements and proposed a number of placements for subwoofers based on a bunch of different factors which is evenness of frequency response R reduction of variation from seat to seat overall gain so when you you know Drive the subwoofer with a certain voltage what does this layout
• 26:00 - 26:30 give you in terms of sound pressure level because some of them interact better with rooms than others and he and he produced this really interesting AES paper the paper itself is is scientific it's a little hard to read but there is a distillate of it available or was available on the Harmon website as a kind of a simplified version please do pick it up Todd Welty so what do you one of the things he said is that among the best Solutions is to put four subwoofers in a room at the quarter points in iCal yes unless you think of the ceiling you
• 26:30 - 27:00 can put four 10in subwoofers hanging from or built into the ceiling of a room as long as you know you worry about the structural issues and the weight bearing and all of that and at the quarter points and you'll get really good base so Legend Number Two is subwoofers need to be on the floor no Bas is propagating evenly in in the room in all directions it doesn't know that it's on the floor on the front and the back what matters more is the interaction between the subwoofer and the rooms and the standing waves and this is a great solution okay
• 27:00 - 27:30 and I've done this a number of times another solution that works well in terms of smoothness and all of that is for subwoofers at the midpoints of the room and that works one of the one of the things about this is it's not particularly a high sound pressure level solution it's not highly efficient but produces very good sound another solution that he's that he's proposed is for in the four corners it's a little less good than this but you get at least 3D more sound pressure sound pressure
• 27:30 - 28:00 level sometimes four or 5db more by Corner loading the group of all four of them and that's worth it because you want Headroom in the base if you can't put four subwoofers just put two either left and right of the middle of the wall or or hey I'm missing that slide or middle of the back middle of the front they fix different standing waves but it's better than a single subwoofer all right so solution one that is either free if you haven't yet bought yourself subwoofers or maybe is a little expensive cuz now you got to buy go buy
• 28:00 - 28:30 a second subwoofer and very good subwoofers are available for not that much money these days is propagate them have more of them so that they actually evenly pressure the room so let's take a look at that in this room we're talking about I'm going to keep going back to what we call the blue room because it's painted with sort of a gray blue actually it was supposed to be a neutral gray and the paint mix was wrong and it ended up with a slight tint of blue we painted it and like oh close enough it's not too far off into the BL um I'll some samples Anthony yeah get me some samples
• 28:30 - 29:00 I should I should have gotten the months old paint and be done with it so remember this is what we had from the single subwoofer locations left Center and right and this is what we get now from four subwoofers in the four corners of the room these are measured this is a little more complicated of a graph it's actually measured at four locations but the average of those four locations is actually the red line so if you follow this red line that shows us an average of the room by just instead of using one
• 29:00 - 29:30 subwoofer at one location you you use four smaller subwoofers they still need you still need them to extend down to 20 HZ and there's people who make smaller subwoofers that play less loud and go down to 20 HZ and and look at how much better this is at multiple locations in the room you got a good solid consistency between 20 HZ and 60 htz then there's some variation up here the average being this red line now we're going to talk about this variation later this is way more better 12 DB peak-to Peak errors without
• 29:30 - 30:00 EQ this is this is unequalized this is just four decent small sub stick them in the corners stick them on the sides four Subs this is what you're getting that's amazing actually so first first strategy is subwoofer placement four is best two is okay experiment a lot sometimes moving them a little bit you'd be amazed by just just moving the subwoofer 4 Ines what effect that's going to have in contradicting the standing wave and getting you much better results and what I like to say is expect drastic
• 30:00 - 30:30 improvements this is not subtle these are big changes going from 38 DB errors to just 12 is highly Audible and way more audible than just changing the speaker wires that go to the subwoofer which some people try to fix things or they put them on little little feet to help improve the thing no dude just understand the standing wave interactions and that's what's really going to make a huge difference well especially as you get in you know here we've got although you have three seats there but you know when you get into theaters that have you know three seats
• 30:30 - 31:00 six seats multiple rows you're really looking at a spot where you know it's it's not two channel where you're listening at one key spot so yeah you know if if I can fix at multiple locations by using multiple Subs you know and and help improve that sound and reduce you know that that big 30 DB you know drop down to 12 that means I'm going to get more even sound you know throughout the room right which is which is what I want if I'm putting that many
• 31:00 - 31:30 that many seats in a room I expect them to be good so so that's one thing that home theater or home Cinema has introduced is the fact that it's not a solitary experience a lot of audio files are like dude I want to get away from everybody I'm going to sit here with my glass of conac or wine or juice and I'm just going to listen to music at this you location you you can find a good subwar for place where the sound is decent to find it don't just listen I I have people that sit around and they're listening to program material dude get
• 31:30 - 32:00 room EQ wizard it's cheap get a microphone 70 bucks put it at your location Fe the subwoofer if you want with you know going back to what what Craig Todd asked a little while ago just play What's called Pink There You Go simple play What's called pink PN in room EQ wizard which is a pseudo random sequence you can choose the number of points I use a 64 it's basically playing 64,000 different frequencies in a in a in a cycle and you can actually hear the CLE it kind of goes and the measurement device is
• 32:00 - 32:30 looking for that cycle and it very quickly gives you data way faster than a regular RTA and just put the subwofer on a dolly move it around while looking at the screen of your laptop computer whatever you're using and you'll find a place where it's less bad that's if it's one seating location solitary experience and if the listeners here that's all they care about done but you're bringing up a good point which is a lot of a lot of folks like home Cinema or if you like music
• 32:30 - 33:00 you may want to have two or three buddies over listening to music together and you want everybody to have good good base so don't just measure one point you got to measure multiple points and when you start to measure multiple points you will find it's really difficult to get them to all be good with a single subwoofer that's where two subwoofers or four subwoofers comes in to smooth out the response I'll show you later my kind of simple science explanation of how that works but just trust me for now Robert Bush says put sub on a dolly and
• 33:00 - 33:30 move and groove why put it on a dolly subers are heavy because they're heavy I don't want anybody to come back to me and go I broke my back moving my subwoofer around that's right they're heavy but also by putting it on a dolly and moving it slowly and observing the results on your screen of the response of that you can have a Continuum as opposed to pick up and move where you have this like this big chunk transition so just moving it evenly is a way to do it you know get a little plant Dolly with decent wheels that can support your
• 33:30 - 34:00 300 lb subw Warfare you'll be fine so Frank asks a good question is why do theaters like the film Academy follow the the four subw warer rules and only have them at the front so that's a really cool question I'm going to get into actually right now by Coral are the short answer is their standing waves in these big rooms are at five Hertz 5 to 8 10 Hertz because their rooms are big enough that the standing WS instead of being in the 50 60 70 htz region they're way lower in frequency so by the time Frank you're listening to the base
• 34:00 - 34:30 you're putting in the room is no longer resonant it's it's Way Beyond its what's known in in Acoustics as its modal region it's it's a point at which you're past where the room has standing weights so I mentioned this thing about low frequency you know below the modal region yeah and interestingly enough there's a there's a lot of interest in what's called infrasonic now in home Cinema and and what is that I mean it's it's all over the forums it's all over it was all over at the CD Expo what is
• 34:30 - 35:00 that and what it was in for Sonic so what does the language mean I'll I'll just give you my interpretation first of all to me a subwoofer is a device that was used you know when the term was first coined by the likes of mnk and K kinergetics and there's other people who started making those it was a device that made was meant to play below where the woer of a typical speaker in that era cut off which is about 40 Herz you know if you go back even today you
• 35:00 - 35:30 know people who claim oh this is my full range speaker they they basically play down to 40 or 50 Herz and then poop out they may play lower at low levels but at high levels you're just overdriving the woofers so the idea of a subwoofer is it's really playing the bottom octave from 20 HZ to 40 Herz below the region at which a woofer could play now it also turns out that somewhere around 40 htz your perception of sound goes from a tone where you hear as you as you go down you you you hear the toneo and at some point you stop hearing
• 35:30 - 36:00 it as a tone and it starts to be heard felt as a vibration so this tendency was also somewhere around 30 to 40 Hertz it starts to be more tactile than a than tonal and so that's kind of like the world of Subs now most subwoofers typically play from down to 20 HZ sometimes they play all the way up to 200 but really they they basically poop out at 20 and does sound go below 20 HZ well it does big pipe organs play
• 36:00 - 36:30 all the way down to 16 Herz and they're not HT as a tone it's more like a vibration and there's stuff in film soundtracks and in music that is way down in there and there's folks out there that are measuring it whether we're supposed to be heard or not is unclear and Frank may be able to chime in and go yeah there's stuff down there in this film soundtrack I did that's in the 12 htz I never intended it it's just a result of signal processing or whatever but whether it's it's meant to be heard it's nice to be able to play all the way down to 10 HZ 12 Herz so so
• 36:30 - 37:00 anything that's there you can play back now there's good news the bad the bad news would be holy moly I need to have four subwoofers that all play down to 10 Hertz those are monsters these are like 24 in drivers or 32in drivers well not everything I'm talking today is Doom and Gloom if you want to play all the way down to 12 HZ 13 Herz Whatever frequency you're trying to get to one approach is to put four mahanga subwoofers in the room and you know I make subwoofers I'd love to sell you are 21 in you don't need it
• 37:00 - 37:30 what you need is a sub there four subwoofers in the corners that are tackling the region of Base that is what is known in Acoustics as modal the region where there are standing waves and that's typically in most rooms about 40 Hertz up to about 80 or 90 Hertz so new thinking there is a region of Base from about 80 Herz down to 40 Hertz 30 to 40 Hertz where the room has standing waves that's where you want to propagate these four subers then do something to tune them which we'll talk about later
• 37:30 - 38:00 below that you don't need to worry about it again because the room is you're now below the resonance frequency of the room and you can just have one infrasonic subwoofer or two how whatever it takes to drive enough sound pressure level this is just horsepower so a small room you could probably get somebody's actually I'll mention them SVS I'm jealous of those guys they make incredibly good sub for the money there's other people who do too but they make some 16in subwoofers
• 38:00 - 38:30 that play well down into 15 Herz for not that much money and they play loud so if you have a room that's around 300 Square F feet 30 square meters you could probably get away with one of their Monga 16-inch subwoofers to drive the infrasonic region okay a single one don't just do a single one for everything but fine you know you now you then you have to cross it over which is a discussion for a later time but you could do that or to if you have a bigger room or a bigger subwoofer or whatever
• 38:30 - 39:00 I'm I'm actually tempted to go back to this slide remember this what in this room is the modal region well you see down here this this here looks kind of like what the anaco response looked like so this particular room below 30 Hertz just supported the anaco character of the of the the subwofer and it problems really started at about 35 Hertz and from here up to here you're mainly dealing with standing waves the modal region of the room so this room I would
• 39:00 - 39:30 say from 35 Hertz to about 80 75 or 80 Hertz this particular room had standing wave issues above that don't worry about standing waves there's other problems below that don't worry about standing waves so a thinking in the world of infrasonic is have four subwoofers that carry the 30 30 or 40 Hertz up to 80 or 90 Herz wherever you're Crossing to your speakers and then below that a single or two or three or however many it takes to get the sound pressure level where you don't need to worry about standing wave
• 39:30 - 40:00 character so if you remember those diagrams I showed be before that showed you know the first the first resonance is where half a wave fits in the room right and in the case of I'm just going to cite an example of a a 20 foot room 6 meters that first frequency is 25 htz okay below that there are no standing waves in fact in a in a typical us Construction us Australia places where they build with gyps and board on studs
• 40:00 - 40:30 below 30 or 35 Hertz the the walls are flexing so they're not really even keeping the standing wave so when when there's no more standing waves you don't need to worry about it and and this is I'm going to just I guess I'm going to share screen again this is kind of how the placement and interaction in the room works again in sort of a simple diagrammatic form how does this work what what does this business do so uh driving the St standing waves so the worst thing you could do is put it one
• 40:30 - 41:00 side warer in the corner on the front wall because that's driving the standing waves very efficiently which is what you don't want efficiency means that some notes are really loud but other notes are really quiet so you don't really want that if you move the subwoofer away from there you can improve the response by moving it so that whole business I talked about earlier that you can put a dolly on a subwoofer and observe its result that that's just noticing the result here's how that works so so here's an interesting piece of info
• 41:00 - 41:30 remember this representation of the first harmonic which is this is a wave that in which half way fits in the room the resulting sound pressure which is what I'm showing here looks like this it's loud here it's loud there and it's totally quiet here interesting thing is this is called a node and it is like the the the pivot of a seesaw the sound is actually going like this interestingly enough at that null there's no sound on one side of the null the when the
• 41:30 - 42:00 pressure is positive it's negative on the other side so it actually flips polarity on either side and it's kind of cool you can actually hear this uh you won't hear this at 25 htz but if you have a standing wave at like 80 or 90 Hertz then you put yourself right in the null on one one side of the null you're going to hear 80 htz on the other side you're going to hear 80 Herz and right at the null you're going to get that sense that it's out of phase that sense that you get from two speakers in Stereo that one is connected backwards it's kind of this funny head cold sense like like wow weird that's a true standing
• 42:00 - 42:30 wave so the acoustic polarity changes around the null so who cares well imagine you have you put a subwoofer here that subwoofer is going to drive the standing wave there's going to be when there is positive pressure here there's negative pressure here there's a null here don't sit here but check out what happens when you put the subwoofer right at the null the subwoofer wants to the the standing wave wants to go like this the pressure polarity wants to go like this get around my microphone but the
• 42:30 - 43:00 subwoofer wants to push it up and down evenly because the cone's right in the null so instead of the standing wave developing naturally you've now contradicted because you wanted to do this and so instead of getting this big standing wave gain at one frequency and then anull at another frequency you've just tamed it by moving the subwofer into the null and that's what's happening when you're listening to the standing waves in your moving the subwoofer on a dolly actually if somebody could build a
• 43:00 - 43:30 motorized Dolly with like big enough engines with a remote control that you could just sit at your seat and listen while you move the thing around that would be really really cool this guy Grant Imahara used to work for me at THX went on to ilm and then to MythBusters and he loved remote control things and he was going to build me one of these like ballsy ones so you could put a 200 lb subwoofer on it and move it around never got around to it but so this is this is what happens so the the subwoofer drives the pressure minimum when you are at frequencies that are below that region you can move the
• 43:30 - 44:00 subwoofer as you want and it's not going to change things very much so here you get less resonance it's cool going back to an actual room this is an example of you sitting on your chair wearing a red hat and a blue suit and some Red Socks it's a very good look on you like I often do yeah where if you'd put the subwo on the front wall and let's say let's say the room is 20 ft long and you're you're actually playing 50 htz in this case you're going to get this kind of profile to the sound pressure so um
• 44:00 - 44:30 loud here loud here loud here and no sound at 50 HZ where you're sitting not good right so you should have a like a frown like it's not good subwofer is over here there's if you could measure the pressure polarity you would see it's positive here it's negative there it's positive there or if you get up and turn right at 50 HZ you may be able to hear it you turn your head sideways you'll hear that it's out of phase you move the subwofer from that location you bring it into the room to drive one of the nulls
• 44:30 - 45:00 the resulting errors go down there's still some error it's still not great but it's less bad right so instead of moving the subw warer what happens if you put two of them so if you put two subwoofers on either side of the null and you connect them together the standing wave wants to do this but you got two subwoofers that are doing this to the standing wave now what happens is less standing wave so that's a simple View of what happens when you go from a single subwoofer to dual subwoofers in
• 45:00 - 45:30 the front and back in the left and right is you're cancelling at least the odd order of standing waves which is the first the third and the fifth same thing if I go back to a drawing of the room that's two subwoofers one here and one there and you're getting rid of what would be in this case the second harmonic so if I propagate that across the four harmonics that we care about this is the pressure polarity at the first harmonic that's the one where the wave is twice as long as the room pressure polarity of the second harmonic
• 45:30 - 46:00 that's when the when the wave is the same length of the room it goes plusus plus this is a third harmonic when the wave is one and a half plusus plus minus fourth harmonic when two waves fit in the room plusus plusus plus minus so if you use a single subwoofer and you put it in the corner it's going to drive those harmonics if you move if you can move it over you'll reduce it and here's a range of all the different harmonics you could consider putting a subwoofer at to redu the effects or you can just use multiples so check it out if we put
• 46:00 - 46:30 two subwoofers in the room we get rid of that what I had shown before as as the first harmonic and we get rid of the third harmonic but the second harmonic is still there MH right because this is plus minus plus hey at least you've reduced some of the standing waves there's one left out of three or four that's when the two other subwoofers come in handy right if you if you can put them in another location of the room where they're canceling that you're reducing that effect and that's
• 46:30 - 47:00 that's what that whole thing is about placing multiple subwoofers in the room or same thing with speakers if you know this if the room is small enough the standing waves go up to 100 120 hertz and if you place the speakers correctly in the room you will reduce the the efficiency of the standing waves bottom line is move the subwoofers away from just a single corner from the front wall try playing them around multiply them to two or three or four I haven't found that five is a whole lot better at some point the Improvement is
• 47:00 - 47:30 pretty benign and actually that's what Todd found in his both his theoretical research and his practical research back 20 years ago so typically four subwoofers in the four corners or other places is a great way to improve things and then I'm guessing past that is really just SPL levels right so if you're putting in either bigger drivers or more drivers you're not improving standing weight you're just increasing SPL at that point correct correct that's
• 47:30 - 48:00 that's where it gets better so in the end though to get that thump or if in a movie soundtrack you know something big is happening and you want to have the sense of catastrophic vibration you need some pressure level so you're not in a big room you're not going to get there from four small 10in subwoofers you're just not you need enough some pressure level and go back to the beginning which is you need enough cone area to get there it's just that when you're multiplying it to four subwoofers you you just need four smaller subwoofers
• 48:00 - 48:30 than you would have needed theoretically for one one big unit in the room that's a good question where where do they kick in what frequency do you kick in so in the olden days before surround processors with subw warer filters and base management which I've been around for a long time now you know that what I'm describing here has been around since 199 596 so this is not new but in the olden days the subw Warfare would have a a a a filter frequency and you could actually take the signals from
• 48:30 - 49:00 your preamplifier run them through the subwoofer produce a high pass filter at also either a selectable to the same frequency so where is that frequency so one one approach if you're not considering standing waves which you which would be a big error was just to say well my speakers play down to 40 HZ most my subwoofer is taking off from there that was the original intention of subwoofers but enter standing waves so in the room I've been showing you the standing way started around 80 HZ my recommendation is kick them in somewhere
• 49:00 - 49:30 around 80 HZ even if the speakers can go below that you've got major problems with standing waves that you're going to solve by using multiple subwoofers strategically located in tune so let me share this so I talked about a multi-point strategy to making to making this all good and the first point was choose your subwoofer correctly and place it correctly I hope I've beat that to death the second one is choose the crossover uh location correctly that's pretty quick so you basically want the
• 49:30 - 50:00 system you're playing with to sum all of the base at a frequency that you've decided I'll get to that in a second and sum it all to the subwoofer and that crossover is based on what what's the what's the base capability of your speakers and where the room needs the help from the subwoofer so this is a block diagram of the subwoofer filter in a surround process sometimes people call those avrs avcs I
• 50:00 - 50:30 call them controllers whether or not they have an amp in them but you're you're normally going to sum all of the base from all of the speakers together and feed them through a low pass filter to a subwoofer output then an assign that to multiple subwoofers and the speakers are going to play a high pass filtered version of that which means you're you're cutting off the Bas at some frequency so decision on that is is basically determining what your speakers can do again and what the room is is is is capable of of doing
• 50:30 - 51:00 so first of all what your speakers can do I have read so many brochures from manufacturers that say oh this speaker extends all the way down to 30 Herz right then you measure it by doing the same measurement I just did which just take the speaker put a microphone right in the cone preferably outside at a moderate level just playing 70 or 80 DB and you realize the speaker dies out below 70 htz what what are they saying it goes down to 40 or 30 and you read the fine print and it's it either tells you bandwidth which just means it has
• 51:00 - 51:30 some sound or if you read carefully it says that's the minus 10 DB point so it's saying I you know I can play sound at 200 100 htz actually in your direction and then and then there's still sound at 40 DB but at 40 HZ but it's 10 DB down that's useless that means it's basically gone I want to know where the 3db down point is and on a lot of speakers that's 70 80 Hertz you can do this Rew a simple little microphone you know measure your own speakers or
• 51:30 - 52:00 look at data from some of the compan some of the the websites where they they were measuring these things and they'll they'll tell you but don't only do it at low level some speakers can play down to 40 HZ at low level but when you crank them up when you when you need the impact the Dynamics the woofers are running out of steam they're either going into Power compression if it's an active speaker the amplifier's clipping or you're dangerously damaging your woer to where it could the woer of the speaker to where it could actually fail so you need to check it at different
• 52:00 - 52:30 levels U observe the Distortion listen whether it's going you know just overloading generally you want to choose from the speaker alone this is disregarding standing waves in the room choose a crossover frequency that's where the speaker is down 3db from the main the main pass band this is an example of a speaker I was measuring it shows that somewhere around somewhere around 80 HZ this thing is down 2 to 3 DB this speaker should be Crossover at 80 Hertz whether or not there are standing waves then the next thing is so
• 52:30 - 53:00 one factor again is how low can the speaker go second factors what's this what's the room doing to you clearly in this room there are problems What's called the the modal region the standing wave region clearly to me below 80 htz things are getting kind of ugly where you see these big differences so if you're using an 80 HZ speaker a speaker that can blade down a 80 hurts in your measurement in a room like this cross cross it over at 80 it's that simple
• 53:00 - 53:30 sometimes a room is good down to 60 because it's a big room has very floppy walls it's an open floor plan that goes into the kitchen and the hallway and there's no standing ways because they're all just dispersing whatever it is you you you do some quick measurements and you'll find out on average 80 htz is a good starting point most speakers can play down that much and most rooms become modal start to have serious standing waves somewhere around that frequency and from that point on you're going to tune the level of the subwoofer and the and the delay and other factors
• 53:30 - 54:00 in that in that process so Brett I'm going to I'm going to continue on here and talk about the tuning so now you're in the point just to summarize in all this is you got a room you've decided to spring for four subwoofers four smaller ones you know four 12s or 41 if your room is not that big you've placed them in the four corners you've decided you're going to cross them over at 80 or 85 or 90 wherever is right are you done well you could be you've gotten a lot better than you were before or or than
• 54:00 - 54:30 what where you would be if you hadn't done any any kind of Base management but there's one more thing you can do with optimization so to do this right ideally you want to measure uh just as a as a a quick primer on this you don't want to just measure one location you want to measure a few locations around the listening area the main seat where you may sit but maybe a seat to the right a seat to the left maybe behind in front wherever there's going to be seats or just get an average
• 54:30 - 55:00 of the room with four microphone locations if you're really classy about this you buy four microphones and you buy a switcher that that actually in the case of Rew you can uh pay a little extra amount of money and it'll give you the ability to switch between the four mics and you got to have an analyzer going to keep going back to this if you want to do good work with this you got to have at least one good USB or regular XLR microphone with an external converter that you can buy from Parts Express or one of the other vendors and
• 55:00 - 55:30 an analyzer again my my recommendation is Rew and the first thing you're going to do in the tuning process is inter subwoofer delays then you're going to do the inter subwoofer level so so see what happens as you change the levels between the subs and then you're going to EQ that whole that those four subers as a group to me it's wrong to measure and equalize one sub War for for flat and another one for flat another one for flat another one for flat because when
• 55:30 - 56:00 you group them back together the response is going to be completely different it's you first want to optimize how they work with each other and then tune the group here's the first step you take the subwoofer output of your surround processor typically a line level either RCA or XLR you plug it into a DSP equalizer for one in for out that equalizer needs to be able to tune frequency response but also set delays differently and the mini DSP box which is a few hundred bucks or this thing that you can
• 56:00 - 56:30 get from Parts Express under under the Dayton audio brand which is called the 4x8 or 408 or 4x8 I guess 408 EQ is 4 input eight output you only need one input to four output that thing's under 200 bucks works great so you are going to feed your four subwoofers equally you're going to feed them all either I I recommend at this point just doing pink PN which is pseudo random pink noise and you're going to measure the results and
• 56:30 - 57:00 you're going to look at what happens as you change the delay between the the subwoofers I usually start by delaying the back subwoofers 2 milliseconds then 4 milliseconds then 6 milliseconds then 8 milliseconds and observe the result then go back to zero and then delay the fronts two milliseconds at a time then delay the two lefts delay the two rights by that point you'll get a pretty good sense uh with what the what the r is doing with your subwoofers you can also try delaying a single subwoofer just go
• 57:00 - 57:30 I'm going to leave three subwoofers at 0 milliseconds I'm going to delay the front left by two four 8 10 milliseconds observe the results the really cool thing with Riki wizard is every setting you can save and you save it in a memory slot and you look at the results ultimately what you're looking for is is the result that is the loudest and the least variation from seat to seat so you're looking for overall gain and smoothness and evenness throughout the
• 57:30 - 58:00 room remember this this is this Listening Room with single subwoofer at a single microphone location 38 DB error this is the same Listening Room with four subwoofers without any optimization they're both they're all four of them are driven together and the average of four microphone measurements is the red line not bad and and this is after running MSO here's the result as measured at the four microphones so what you're looking
• 58:00 - 58:30 for is a smoother res result which actually the green and brown curves look really nice and smooth those are at two of the microphone locations and then the red and blue are two other microphone locations that's not okay so at some microphone locations this scheme improved things substantially in terms of making a really smooth result from 22 Herz up to 1502 200 Herz and at other seats it wasn't good okay that's where you pause and you
• 58:30 - 59:00 go I'm trying to get less variation from C to seat and and good overall response so now I go manual and I do the same thing with just manual adjustments that thing I said which is trying to delay here delay there Advance here change levels and this these are four microphone averages I have the curves for the individuals I'm not showing them here but this was the this mustard color here is the original result with no
• 59:00 - 59:30 optimization no manual optimization and the green curve is the result with manual optimization and we've result we've reduced the errors from 20 DB to 7 DB Peak to Peak which one of these two is better so this is with no optimization this is with optimization they're both not right this one is better why because what we're going to do to this is we're going to apply some Equalization here to turn down this peak and this peak is at 36 HZ 36 HZ gets in gets to be into those low frequencies
• 59:30 - 60:00 where it's hard for the cones to push base and we're going to we we've now gained 3 at 36 HZ we've gained 60b of sensitivity out of the thing it's more efficient and all we do now is we turn that down with one band of parametric EQ not not hard to do inside The Equalizer and we got ourselves 60b more head room at 36 htz than pre-optimization gotcha so what I'm looking for on all this is smoothness of response overall gain overall efficiency
• 60:00 - 60:30 and less variation from seat to seat here's another room different optimization routines let me start with the red the red is four subwoofers no EQ no delay that's what we start with in green is apply delay look at what happened here we got ourselves 12 DB more energy at 67 Hertz that's substantial and then what we're going to do is we're going to sit on this peak we're going to turn it down this is part of the way there so in blue is as we're equalizing it back down to get to a smooth response 12 DB more that's I
• 60:30 - 61:00 think the best case I've ever seen so we're going to add in EQ we're going to smooth that out here's another room in you know before and after EQ before DeLay So no delay is in red we got a peak here at 42 Hertz we add delay in this case I don't know 6 milliseconds of delay somewhere and we get ourselves a lot more energy at 23 HZ 60b more that's four times the power to play the bottom
• 61:00 - 61:30 octave and then with with then we apply Equalization to smooth out this green curve and we end up with a nice smooth response that fits in a 2db window all that for a few hundred and the list goes on I've got lots of examples of that in this room we got 60b more at 30 htz by just applying delay and then we equalize it out in this other room uh we added 8 milliseconds of delay and we got 12 DB of overall gain over you know the region from 40 HZ to 80 HZ unbelievable this
• 61:30 - 62:00 room went from having puny base nothing no impact cammo using a series of small 8in woofers in a pretty big room interestingly enough this is the progression in that room as you went in two milliseconds of delay I forget if it was the front or the back this is back where this was the original 2 468 Etc so that's kind of a cool progression so I talked to about delay but also you want to do the inter subwoofer levels to do the same thing and then you equalize the
• 62:00 - 62:30 whole result in one go and you end up with Stellar base you set the overall level so that it matches your speakers maybe a little hotter than the mid-range and you get you get that base that everybody's looking for it's very cool well very cool so I know we were talking about seating locations a little bit earlier we've now put Subs into different areas are there better places to sit how do you look at that when you're designing room Anthony so we talked earlier about how hey there's standing wave Peaks and nulls
• 62:30 - 63:00 and you were saying my God there's nowhere I can sit in here it's like well there kind of is if you did nothing with a subw for placement at least you could sit to at a place where there's no big Peaks or nulls but then you can if you just using one subwoofer you can move it to where it's less bad and then choose your seating location and sometimes just moving it 6 Ines is all it takes to get out of a big peak or a all you're going to know it by listening to it but even better by just putting a microphone there and moving it around so just like you move the subwoofer around you also maybe move the microphone around and see
• 63:00 - 63:30 what happens as you move left to right front to back is there a place where suddenly the base gets good remember that's just one seed location I'm going to show you some kind of simple guidelines for what what we like to to look at so let me share my screen again oh by the way before I forget this is the same room that was read originally we we repainted it it's blue now with the four subwoofers this is this is in its current state if you came to our office and looked at it this is what you would see this is an acoustically transparent screen there's a left there's a center and a right speaker we
• 63:30 - 64:00 also make speakers that can go above and below the screen so if you want to hear what that sounds like but there's two of the subwoofers in the front these are relatively skinny subwoofers with a 13-in super thin subwoofer is there a picture of the back oh there's there's a picture showing all the microphones set up for these tests one two 3 four the bass guitar no longer play anyway so in the seating locations you don't want to sit here you don't want to sit there you don't want to sit there you don't want to sit at the nulls you don't want to
• 64:00 - 64:30 sit at the Peaks but check it out if you if you look at all of those those Peaks and dips and you look at places where you're at neither a peak or a dip look at this dotted line over here if you sit here which is 02 of the length of the room right up against the speakers which I don't recommend doing if your speakers are here that's too close but if you sit back 80% of the room you're neither at a deep null nor at a big peak I don't usually like the sound you know 80% of the way back in the room but if
• 64:30 - 65:00 you want to be that far you can another one is at 68 of the room if you sit here you're not at a null you're not at a big peak you're a bit of a peak over here but that's a good place somewhere right around here 7 68 or 7 if you sit at 0.55 of the length of the room you're neither at a big peak and all if you sit at half of the room it's going to suck if you sit at 045 it's pretty good if you sit at 32 so what I like to do in the beginning of setting up a room is look
• 65:00 - 65:30 at the length of the room look at the width and try to seat put seat locations at uh. 32555 3245 55.68 or8 of the room as a start point and then measure it because some rooms are going to behave slightly differently to that here's a little chart that shows the same thing on on all three axes front to back left to right and top to bottom so top to bottom is important too standing WS don't just happen in this Direction They also
• 65:30 - 66:00 happen in this direction and I've worked on Plenty of rooms where right at the seat position there's a giant Gull and sometimes all it takes is to build a little platform that you sit on to get yourself out of the null that platform may as well be perforated or slotted and turned into a bit of a bass trap too you brought up bass traps in there Anthony we built this room we' put in Subs we've got some general guidelines as to where we're putting our seating what do we look at for base damping what what do we look at for Bas traps so remember in the beginning of this I talked about these
• 66:00 - 66:30 waves bouncing back and forth freely we talked about how to reduce their drive by using multiple subwoofers or putting them in the way in a basically putting them in the way of the standing wave we talked about not sitting where the nulls are we talked about tuning it out but what if you did something in the room so the sound doesn't bounce back and forth in the base and that's the domain of Base damping base absorption people say that they're going to implement a Bas trap or they're going to buy a Bas track and there's a giant caveat mtor a lot of
• 66:30 - 67:00 companies build things and sell them as Bas traps they AR they aren't base traps at all they're they're chunks of foam you put in the corner that absorb 200 Herz and nothing below that they're not getting rid of standing waves and that's un or unless your room is only like 10t by 11t or or smaller standing waves are mainly in the 60 to 80 Herz region which means that you you got to have really big devices if they're going to be foam that doesn't really work you do want some kind of Bas damping so if we can do
• 67:00 - 67:30 something so the base doesn't roll freely back and forth in the room it's worth it so let me let me talk about base damping rather than base traps I just think of it as damping and it's not dampening dampening is the act of putting water on something damping is reducing the oscillation so one approach would be to do base absorption using fiberglass foam recycled genes something fibrous something that offers resistance to the free flow of of waves and scrubs it off
• 67:30 - 68:00 through through friction for it to work at 60 htz or 70 htz it's going to have to be really thick like four five six feet thick it's just not practical so in in order to get rid of like if we pretended we were talking about our our 20 foot room 6 M where you have a null you're going to need to have an absorber that's a that's an of the way into the room which is 76 CM thick that's big
• 68:00 - 68:30 okay that's about you know 2 and 1 12et 3 feet big it's not practical it works but it's not practical so you can also put instead of a big chunk you can you can put an absorber panel right at the null that works also it's still not very practical it does work you can put them in the corners you can take absorber panels and put them in the corners so that there's some air gap behind it it works okay it'll work down to 70 maybe sometimes 60
• 68:30 - 69:00 hertz if if the panel is big enough it can work but it can't be just thin foam that's lightweight it has to be a pretty heavyduty material for it to work and I get calls and emails all the time from like hey I have terrible problems in my base I bought this Basse trap and it hasn't changed anything I measured I listen to it what what's going on well you just bought this little chunk of foam that you stuck in the corner that's too thin the base waves are just hitting it and laughing at it and going back around it's like like driving over a a a coin with your car you don't even know it's there you need things that are more
• 69:00 - 69:30 substantial so when you're talking about more substantial one thing that people either buy or build is diaphragm absorbers which are giant drum drum heads like just a giant frame with either plywood or some other resonant material that you can calculate by looking at some equations you can find on the internet it's a bit complicated to build if you're using wood it will be unreliable because the plywood layer will change its density and its and its flexure with humidity and temperature so
• 69:30 - 70:00 we've done these many times before and notice they change day by day it's not not very it's not the right way to build a room so if you're going to do those use a flexal membrane that's not porous or not sensitive to humidity another way you can do base stamping is what's called Helm holes absorbers which are resonators you using kind of a wine bottle effect where at one at one frequency the sound goes through the neck of the box and it loses energy
• 70:00 - 70:30 through friction uh that can work pretty well these boxes are big there's people who make them you can build them yourself you can find internet equations but they need to be really big for the frequencies we're talking about which is 60 to 80 Hertz you know like they're Giant coffin siiz things with big holes not very not very practical more practical is actually the intersection of the two above which is a frame about about five four to five in deep so around you know 10 to 15 cm deep that
• 70:30 - 71:00 you has a perforated panel and has a little bit of absorption inside and now you're combining a flexural panel with a Helm Holtz absorber Allin one that can work pretty well and doesn't take a lot of depth it you do you do need still still need to have pretty big surface area there are equations on the internet I'm not going to go there if you're interested in doing that look it up just just call you know look up perforated absorber panel or something like that you can also buy them from some
• 71:00 - 71:30 manufacturers or if you're building a room from scratch you can actually intentionally build damped walls so instead of having a really stiff wall that the standing we bounces back and forth from if you build it out of these rubber isolators there's a few different models out there where the sheetrock is mounted on this rubber isolator maybe with a little backing of plywood then when the wave hits it the the the the sheetrock actually moves the gypsum board I should call it sheetrock is a
• 71:30 - 72:00 brand it moves a little bit and every time it moves it dissipates a little bit of energy it changes the phase of what rotates back and it it will dissipate your standing waves a lot so I'm a big fan of using either this thing called the pack which is Pacific International rsc1 which is a clip you put onto the studs and looks like this so here's your stud you screw the clip into there you put a piece of hatch Channel and put your sheet rock on there or there's a model from Kinetics noise control that
• 72:00 - 72:30 is same kind of result it's a block like this that you put a hat channel into you screw the sheetrock through the Hat Channel using uh sheet uh sheet metal sheet rock screws does the same thing but the main thing is you now have let me go back to this drawing you now have walls that are damped that actually can Flex a little bit and you have an added bonus which is you now built a room that's sound isolated because instead of the sound transmitting to the studs and
• 72:30 - 73:00 out to the neighboring room it's contained in the room so if you're building from scratch you can just build a room with these sound isolation clips and you will result in way better standing wave characteristics way better just to go back to a bunch of people make base traps cavat Amor which means buyer beware in Latin they speak that in Latin America no they don't maybe they do some people and so how are you beware well if you're going to buy if you spend
• 73:00 - 73:30 a bunch of money on somebody's base traps ask for the data make sure the data doesn't look like a chart that they just drew on the back of a napkin but it actually comes from a laboratory and make sure it's effective down to 40 htz and there's no two ways about it the good stuff is going to cost more if it's cheap it probably works that well which is no good so so Solutions are either good base absorbers that work clearly down to 40 45 Hertz they're
• 73:30 - 74:00 usually big they're expensive hey if this audio thing matters to you you're going to spend the money on it don't spend the money on really expensive wires that's not going to change your your base response spend it on good base base stps or if you can build a room or tear down your sheetrock if the room's already built put these these isolators in it's going to cost some money but the the Improvement on sound isolation and on base response is substantial well worth it David was asking and this kind
• 74:00 - 74:30 of fits into you know golden ratios and looking at room design so what about non-rectangular rooms trapezoidal walls you know what what are your thoughts as you're designing and building room in there Anthony and how that relates to base management so room dimensions are a big conversation around standing waves and they're extremely complicated and confusing and I will say that trapezoidal rooms don't help they change things and they don't help so let me share my screen again and show you some
• 74:30 - 75:00 data so room dimensions are critical in a way in standing waves because the resonance between the front and back and the left and right are going to be there what you want ideally is not to have the same residences from the front to the back the left to the right and the top to the bottom so if you built a cubic concrete room that would be a disaster except for one fact which is interesting but if you built a cubic room that's like 20t x 20t x 20t all solid concrete that resonates exactly at the
• 75:00 - 75:30 frequencies you expect you're going to end up with standing waves that are all at exactly the same frequency and that's going to be horrible it's going to be a triple whammy what you want to do is to build a room in which the resonances from front to back are at different frequencies than left to right and different frequencies than top to bottom and so you can predict that you think you can predict it actually the accepted thing is to avoid a condition where you have a resonance along the length and along the width that are at the same frequency or close to that so you can calculate it
• 75:30 - 76:00 calculate the resonances by using this equation this is basically the speed of sound in feet divided by two times the distance either front to back left to right top to bottom and here it is in meter n being one is the first resonance two is a second or first harmonic second harmonic third fourth you don't really need to calculate past fourth and what you're really interested in is the region of the room where it is modal now here's an interesting thing for you
• 76:00 - 76:30 total Geeks you can figure out based on the size of the room the range in which you're going to have standing Waves by this equation this below F1 which is 172 times the length or 565 times the length depending on whether you're in meters or feet is going to be pretty much the region below which they aren't standing waves to worry about F2 which is the highest frequency you can calculate by this equation depending on whether you're in metric or in Imperial and
• 76:30 - 77:00 there it is so you you can do all of that caveat mtor again here or calculator mtor here's an interesting thing let me go go forward there's a lot of really cool geeky info but I want to bring this up F Alton Everest very well-known acoustician said that predicting modal response with certainty is very difficult working from General guidelines and recommendations the modal response of each room must be considered on a case-by Case basis that's scientific speak for going it's not so easy this guy is very smart if
• 77:00 - 77:30 you guys want to pick up one book and read about room Acoustics read the handbook of Acoustics by F Alton Everest this sky is excellent I actually my son's middle name is Alton partially after him remember we had a big problem let me go back in the actual measurements in the room we have a problem at 38 a problem at 50 and then there's also a problem at 72 over here and then you look at the predictions and none of that is there there's one prediction at 71.2 on the length it's a second harmonic of the length which
• 77:30 - 78:00 actually at the microphone location should have resulted in a dip not a peak this is really frustrating I have this giant Excel spreadsheet that can calculated and it doesn't work why because this room is built out of sheet rock on studs gypson board on studs so at those low frequencies it bends around differently on the left wall the right wall the front wall back wall non-symmetrically there's a door here and a door there they at slightly different positions so this whole
• 78:00 - 78:30 calculation thing that people are doing from calculators on the internet Excel spreadsheets if you're not in a concrete box it's not relevant you really want to measure it how do you measure it roomy Q wizard give them 50 bucks or 100 bucks buy a microphone you got a great tool now the the second part of this question is what about rooms that are non-symmetrical doesn't get rid of things I've built plenty of these I've been in plenty of those I are the standing waves they're equally bad but they're not predictable so it doesn't get rid of standing waves there still
• 78:30 - 79:00 our residences this shape that I called a coffin box it complicates the acoustic modeling calculations it doesn't get rid of standing waves it just moves them and the standing wave lines instead of being along predictable left to right or front to back ranges start to bend around don't believe me my buddy F Alton Everest has this in his book here's a a a comparison of a rectangular space playing a first harmonic at 34
• 79:00 - 79:30 Herz along the width where there's a nice Gull along the whole ridge from front to back it's it's 100% here minus 100% there 100 DB it's polarity is flipped and here there's zero you take that same room same room size and you bend it here's the standing waves there's still a standing wave it's still 100 here it's 70 there 40 there so maybe you could say well it's not as loud as in that corner while nobody's sitting in that corner there's still a null along here it's just unpredictable didn't get rid of it it
• 79:30 - 80:00 just made it harder to figure out where it's going to be but at least with a rectangular room the walls aren't working against you as well and creating additional issues the line is basically straight whereas when you start getting into trapezoidal rooms and and other non-parallel rooms you're just adding more and more complexity to it that you still have to end up working out anyways you still need to do something so this is the first harmonic along the width and the third harmonic along the length where it shows I don't if you can see it
• 80:00 - 80:30 there's a ridge over here and then ridge ridge ridge that's a third harmonic rectangular this is what it looks like whatever you want to call this nonrectangular non-p parallel a pip head there still are problems they're just in a different place you can say that the ridges are less steep but they're still problems and Murphy's first law of Acoustics is you're going to put the mix position right here where there's a null yeah U and you're going to put the the the producer's couch right here where there's also a null this go goes on this
• 80:30 - 81:00 is all in in his book here's the the third harmonic just lengthwise you can see there's there's ridges over here there's still ridges over there it doesn't really help it's more complicated to build it's really hard to make the non-square corners have good sound isolation it's hard to join them to where the sound doesn't leak out you're losing real estate because in many cases those other areas are just voided it just doesn't help my view of it is you want to take control of those standing waves and you want to do
• 81:00 - 81:30 everything the room sizing yes you want to put the seats at the right locations you want to place the subwoofers do multiples at the right location you want to do some damping absorption and Equalization and if you do all six of these things I'm running out of fingers over here then you run a chance of getting that nice tight punch even base that's smoother and with better transient and less deviation across the seats you have to think of all those smoother bass louder punchier bass and also less change from seat to seat
• 81:30 - 82:00 whether you're in a two channel Listening Room where you want to have some friends over listening with you if you're in a recording studio where you want across the mixing console you don't want to have big changes or you you don't want the producer in the back hearing something completely different than you or whether you're in a theater or home Cinema where you want all of the seats to have a consistent experience you got to do all this and I call Base management the process of controlling all of this not just one thing thing so I'm putting up our contact info Brett I'm sure you're putting it up there too if there's any questions you can email
• 82:00 - 82:30 info@ grman systems.com our websites are Gman systems.com or pmtd while there's tools that are getting better and better like direct live and tools from trinov and and other brands that's great and it's better than not having anything as much as those tools are there you still want that manual calibration at the end it's that ear at the end of it because people are listening it's it's not just a computer you're going to have multiple seats going in there so you want to make sure that you're getting as even as a
• 82:30 - 83:00 sound response as you can across all those seats not just you know the captain's chair because we're usually not in a two-channel single chair listening environment we've got a a few last questions in here Anthony let me pause we're two hours into this and I'm I'm I have to thank you guys that are that are listening in for your your endurance here this this is amazing you're still here thank you very much it is we got 40 people on the line we still got some questions I have a feeling it's slowing down so hopefully we'll try to knock everybody out in the last couple moments here
• 83:00 - 83:30 asking about using seat risers as big base absorption we talked about that a little bit but if you have any final thoughts on that well you so I mentioned that you know in the the thing about base damping that you can put diaphragm absorbers they don't work very well you can put ported absorbers they don't work very well but you can do the combination which is you know holes inside a box well that box is your Riser and it's tall it's going to be at least 6 Ines usually doesn't provide enough of a riser for Headroom usually it's 8 to 12 to 14 which is you know 20 25 cmers um
• 83:30 - 84:00 but if you use that box with the right perforation on the top not don't perforate the whole thing you got to calculate what are the size of the holes and the distances between them based on your standing wave region in your room and you put a bit of of insulation inside don't overpack it then it'll stop being a low frequency absorber and know put put a little bit in there you will essentially I'm I'm going to say almost free you end up with a wonderful big base absorber that'll get rid of a huge amount of this trouble that makes
• 84:00 - 84:30 perfect sense so I'm gonna combine a few questions so Aubrey and Tony were asking so if you're putting in let's say dual subs if one is out of phase with the other what's happening and then in Tony's question if you were using two subwoofers not four is there an advantage to using opposite Corners because I know you like Corner placement so in Phase or out of phase is a really interesting question trial and error that's part of the trial and error I
• 84:30 - 85:00 didn't mention it I I usually find that you know two or three or four subwoofers just delay is enough to introduce phase shifts between the subwoofer and the standing waves that it fixes it but once in a while putting putting one of the subwoofers completely phase polarity flipped resolves everything you will lose potentially at some frequencies you'll lose efficiency but with the benefit of better response trial and error try it and if you're using one of those DSP gizmos there's always a phase
• 85:00 - 85:30 a polarity button in there they call it phase they shouldn't they should call it polarity and just try it and see hey did I get smoother response at all the seat locations or not and sometimes it does help so that was one of them the other one is with two subwoofers doing the two corners well so if you look through Todd welty's trial and error attempts or his simulations that is not as good as putting them front and back middle of the room or middle of the left and right it's still better than putting the both up front there there is a there's a a
• 85:30 - 86:00 grade for that you can read through the whole paper try it now that's what I always say is just go ahead and try it if it works well well being that you don't get these wild variations in the response and W wild changes from seat to seat it work keep in mind that unless you're in in concrete or concrete block construction the waves are hitting walls that are all bouncing and and working in different ways like they do in our room over here and so you never really know you know you you you like to think
• 86:00 - 86:30 things in orderly clean ways but the walls are not they're not clean they're reflecting differently so sometimes maybe offsetting them to the left and right of the center line is going to end up with a better result your your answer is time and a dolly there you go there you go well and that follows into what you were showing before on the graphs where adding 2 millisecond delays and things like that not just based on distance but you could see where you were actually creating gains that you could then bring down uh to give
• 86:30 - 87:00 Headroom right just goes to show you guys it's not a here's a calculator and be done with it there is a lot of trial and error in there and if you need help with it there are great people like Anthony that are out there willing and ready to help you guys out with your theater designs because it's a big investment for clients and we see people do a theater one time and when they go to the next house they don't do one and a lot of that comes into things like this where we're just putting speakers in we're putting screens in we're going as big as we can but that room just
• 87:00 - 87:30 doesn't sound right whereas if it's done right and we spend the time damping rooms properly building rooms properly adding subwoofers in a way that really reflects on the room people are going to love those rooms they're going to recommend you more they're going to bring you into more jobs and they're going to bring you in when they move into the next one so right any any final thoughts in there Anthony as we kind of close this out it looks like we got all the questions answered so thank you guys again for everybody that hung on yeah my final thoughts is is exactly you said thanks for listening to this whole thing
• 87:30 - 88:00 for two and whatever this two and quarter hours and base is important and it's difficult and our company focuses on that whether we're doing engineering work to help design these things or tune them or whether we're building speakers for them all include four subwoofers and people go why why do these things have four subwoofers and now I can say watch the webinar and just because if you don't do that it's really hard to get decent Bas in addition to the video which everybody will get we also have
• 88:00 - 88:30 the five-part article so again give that a read through it's a great article that Anthony spent a lot of time writing and so we want to be able to give it to you guys I think next time we will probably be looking at something like aes67 got to talk a little networked audio and we may have some additional special guest make sure you guys keep an eye out for any emails coming from Anthony and we'll talk to you guys soon sayara bye everybody [Music]