Dedicated audio room build thread aka The Big Dig

[sbnx]

I am sure you have great bass response. The way Jim does it with the RTA finds the spot where everything gets smoothed out. The SBIR from the wall behind your speakers is going to be in the very low 20's Hz. The wall behind you is going to be in the 50's Hz. You have two modes in the low-mid 50's so the SBIR is helping smooth all of that out.

 

[bryans]

OK I had the incredible pleasure of visiting Hugh and talking room build and listening to music. I will say without a doubt this is the best room and system setup I have ever heard!

Reading through this post, I know some have questions/suggestions/ideas on what they would do when building a room. Or what Hugh should have done when building his room. Like everything there are plenty of ways of doing things. For me I wouldn't change a thing. I can say without a doubt I wish I could snap my fingers and duplicate his room.

If I go down the path of building a room, this is my blueprint!

 

[HughP3]

OK I had the incredible pleasure of visiting Hugh and talking room build and listening to music. I will say without a doubt this is the best room and system setup I have ever heard!

Reading through this post, I know some have questions/suggestions/ideas on what they would do when building a room. Or what Hugh should have done when building his room. Like everything there are plenty of ways of doing things. For me I wouldn't change a thing. I can say without a doubt I wish I could snap my fingers and duplicate his room.

If I go down the path of building a room, this is my blueprint!

It was my pleasure Bryan, thanks for taking the time to visit. Hope your plans work out for you.

 

[QuadDiffuser]

Hugh, I would love to come visit you, as I will be building a dedicated listening room in the basement of my new home, with the following gross (solid wall/floor/wall) dimensions (not allocating/subtracting for acoustic modules): 4.4m(H) x 7.0m(W) x 11.0m (L), or 14'5" (H) x 23'0" (W) x 36'0"(L). In gross cubic volume, my untreated room will be 1.5x your treated room, which will require heroic amounts of acoustic modules, partially mitigated by the sheer space which will naturally attenuate mid/high frequencies. For the bass, three (out of five) surfaces will be treated with diaphragmatic bass absorbers (solid boxes containing multiple layers of peg boards filled with activated carbon). For the mids/highs, the front wall will be treated with five horizontal sections of P-23 QRDs stacked three high, the first reflection point mid-section of the side walls will be treated with P-17 QRDs, and the ceiling with RPG's Omniffusor-like lightweight 2D diffusors mounted into a 2'x2' grid. I've pored through every word of this thread, as well as countless other room acoustic related forums/YouTubes, and three books on the topic, but any sharing of additional experience/knowledge you might be able to share would be great appreciated!

 

[tinkerphile]

It was my pleasure Bryan, thanks for taking the time to visit. Hope your plans work out for you.

Have you considered design/engineering approaches after the manner of Bogic Petrovic or John Brandt? ...may be cheaper and more effective. Also, I'm not sure why one would want attenuated mids and highs in the final curve. For many afficionados, tailored intentional reflections are very much desired (mids/highs). Just tossing this out there as a helpful suggestion is all.

 

[HughP3]

Hugh, I would love to come visit you, as I will be building a dedicated listening room in the basement of my new home, with the following gross (solid wall/floor/wall) dimensions (not allocating/subtracting for acoustic modules): 4.4m(H) x 8.0m(W) x 11.0m (L), or 14'5" (H) x 26'3" (W) x 26'0"(L). In gross cubic volume, my untreated room will be 1.7x your treated room, which will require heroic amounts of acoustic modules, partially mitigated by the sheer space which will naturally attenuate mid/high frequencies. For the bass, three (out of five) surfaces will be treated with diaphragmatic bass absorbers (solid boxes containing multiple layers of peg boards filled with activated carbon). For the

hi pm‘d you

 

[tinkerphile]

Hugh, I would love to come visit you, as I will be building a dedicated listening room in the basement of my new home, with the following gross (solid wall/floor/wall) dimensions (not allocating/subtracting for acoustic modules): 4.4m(H) x 8.0m(W) x 11.0m (L), or 14'5" (H) x 26'3" (W) x 26'0"(L). In gross cubic volume, my untreated room will be 1.7x your treated room, which will require heroic amounts of acoustic modules, partially mitigated by the sheer space which will naturally attenuate mid/high frequencies. For the bass, three (out of five) surfaces will be treated with diaphragmatic bass absorbers (solid boxes containing multiple layers of peg boards filled with activated carbon). For the mids/highs, the front wall will be treated with five horizontal sections of P-23 QRDs stacked three high, the first reflection point mid-section of the side walls will be treated with P-17 QRDs, and the ceiling with RPG's Omniffusor-like lightweight 2D diffusors mounted into a 2'x2' grid. I've pored through every word of this thread, as well as countless other room acoustic related forums/YouTubes, and three books on the topic, but any sharing of additional experience/knowledge you might be able to share would be great appreciated!

Have you considered design/engineering approaches after the manner of Bogic Petrovic or John Brandt? ...may be cheaper and more effective. Also, I'm not sure why one would want attenuated mids and highs in the final curve. For many afficionados, tailored intentional reflections are very much desired (mids/highs). Just tossing this out there as a helpful suggestion is all.

 

[QuadDiffuser]

Have you considered design/engineering approaches after the manner of Bogic Petrovic or John Brandt? ...may be cheaper and more effective. Also, I'm not sure why one would want attenuated mids and highs in the final curve. For many afficionados, tailored intentional reflections are very much desired (mids/highs). Just tossing this out there as a helpful suggestion is all.

Tinkerphile, I'm not familiar with the room acoustics related work done by either gentlemen, but a cursory search using their names show examples of room treatment for home audio and recording studios which are smaller and "real-sized", different from my upcoming project. Either way, optimizing room acoustics require understanding how the immutable laws of physics with blend with psychoacoustics, subjects which I'm quite familiar with, having read many books, as well as having practical experience as an audiophile for 40+ years.

But any advice you may provide me will be very welcome! Thank you in advance.

Regarding attenuation of mids and highs, I merely said that these phenomena happen *naturally* as a consequence of large distances. Hence, NOT killing the liveliness of the room by adding room treatment to absorb mid/high frequencies, is important. Reflected mid/high frequency energy needs to be preserved as much as possible, but de-correlated and randomized (relative to the main signal) through broadband diffusion.

 

[QuadDiffuser]

Initial results using estimated post acoustical treatment room dimensions (1: 1.5: 2.2) [H x W x L] look quite promising, landing inside the "Bolt Area", with low frequency room nodes reasonably broadly distributed. The big surprise is that shortening the room length to an exact 2x multiple of ceiling height actually REDUCES low frequency room nodes... so the target ratios may now be tweaked to 1: 1.5: 2.0. The big challenge is how to construct and cover the massive amounts of wall space with sufficient (hundreds of?) activated-carbon-filled low frequency absorption units.

 

[kodomo]

Initial results using estimated (post acoustical treatment) room dimensions (1: 1.64: 2.3) [H x W x L] look quite promising, landing inside the "Bolt Area", with low frequency room nodes reasonably broadly distributed. The challenge is how to construct, fit, and cover the massive amounts of wall space with sufficient (hundreds of?) activated-carbon-filled low frequency absorption units. Tinkering with the figures show that a narrower width (closer to 1: 1.5) actually helps improve the low-frequency acoustics by reducing room nodes.

View attachment 100827

Why did you keep the rt60 at 0.6 seconds. I think somewhere around 0.3 to 0.4 seconds would be more appropriate for a listening room. Then it will show you the necessary amount of absorption needed (it will be more than above) and also the relevant schroeder frequency (it will be lower than above).

I also can not understand why you have subtracted the acoustic treatments thickness from the room. The structural walls are the actual room. You do not subtract their thickness from room size unless it is like a room within a room, even then it will be related to materials and construction of the inner shell.

There can be different approaches to lessen the acoustic non linearities of the room than walls with massive carbon absorbers too.

As you see the list of room modes on amroc page, there is also a way to see where they are located (like in that room in 3d window but more detailed) and their relative strength, so as to treat them most efficiently. Your consultant can model the room with a software utilizing comsol physics if they are capable and actually show them to you. You are dedicating a big space and will dedicate reasonable funds, this is not a small project so your consultant should be capable of at least doing that.

 

[tinkerphile]

Tinkerphile, I'm not familiar with the room acoustics related work done by either gentlemen, but a cursory search using their names show examples of room treatment for home audio and recording studios which are smaller and "real-sized", different from my upcoming project. Either way, optimizing room acoustics require the combination of the immutable laws of physics with psychoacoustics, subjects which I'm quite familiar with, having read many books, as well as having practical experience as an audiophile for 40+ years.

But any advice you may provide me will be very welcome! Thank you in advance.

Regarding attenuation of mids and highs, I merely said that these phenomena happen *naturally* as a consequence of large distances. Consequently, NOT killing the liveliness of the room by adding room treatment to absorb mid/high frequencies, is important. Reflected mid/high frequency energy needs to be preserved as much as possible, but de-correlated and randomized (relative to the main signal) through broadband diffusion.

I substantially agree with the important points you make here. I've likely read the same material you've read (the standards). And I like where you're heading with appropriate consideration the physics and psychoacoustics, preservation of mids/highs (even modifying curve to account for a) old fart hearing loss, and b) larger room size. I really do think J. Brandt's LF baffle design is genius and highly effective, not to mention relatively cheap and easy to manage construction-wise. Not only so, but the work he and others have done on diffusion design is top notch.

Now, if we're talking about large/larger space applications, Sam Berkow has some remarkable insights (not that how he understands the science and psychoacoustic considerations are limited in application to only large spaces).

Very best wishes on your project!

 

[QuadDiffuser]

Why did you keep the rt60 at 0.6 seconds. I think somewhere around 0.3 to 0.4 seconds would be more appropriate for a listening room. Then it will show you the necessary amount of absorption needed (it will be more than above) and also the relevant schroeder frequency (it will be lower than above).

I also can not understand why you have subtracted the acoustic treatments thickness from the room. The structural walls are the actual room. You do not subtract their thickness from room size unless it is like a room within a room, even then it will be related to materials and construction of the inner shell.

There can be different approaches to lessen the acoustic non linearities of the room than walls with massive carbon absorbers too.

As you see the list of room modes on amroc page, there is also a way to see where they are located (like in that room in 3d window but more detailed) and their relative strength, so as to treat them most efficiently. Your consultant can model the room with a software utilizing comsol physics if they are capable and actually show them to you. You are dedicating a big space and will dedicate reasonable funds, this is not a small project so your consultant should be capable of at least doing that.

Hi Kodomo, acknowledging your comments expressing astonishment of the assumptions I used on my (repeat: very INITIAL) calculations. I'd especially welcome friendlier comments in the sharing of your considerable experience and knowledge, if my thinking (below) is grossly out of line... many thanks in advance!

1) The Rt60 of 0.6 sec was just the default setting for the AMROC webpage! Absorptive treatments are typically non-linear (especially between 125Hz and 500Hz) and erase all energy above 1kHz so I'm assuming that generic surface area treatment calculations to lower the reverberant field decay via RT60 measurements would not be desirable nor meaningful, because the fact is that they *SUCK*! Broadband quadratic diffusors decorrelating/randomizing midbass/midrange frequencies on the wall boundary proximity points of the main L/R speakers (as well as on the sidewall first reflection points) allowing the randomized but well-balanced reverberant decay to stay "alive" longer, would be FAR more preferable, compared to absorption treatment which will aggressively and selectively suck out frequencies above vocal-range fundamentals.

Even the AMROC parameter of "critical listening distance" is based on the theoretical assumption that reflections are correlated (in-phase) to the main acoustic signal, as that's what one hears in a typical listening room. But once the indirect acoustic energy/reflections are de-correlated and randomized in both amplitude and time domain, the psychoacoustical signal-to-noise ratio shoots up considerably, allowing more distance between the source and the listening position WITHOUT dilution of the realism of soundstage recreation, as the ear-brain mechanism has a much easier time processing the main L/R stereo channel signals without becoming confused with deleterious direct-reflections. I speak from experience, as my smaller listening room has extensive treatment using P17 and P13 quadratic diffusors.

2) Theoretically, the SUBTRACTION of acoustic treatment thickness/volume would not make sense for the lowest frequencies below 60Hz because those acoustic waves are unaffected by anything but solid walls - as the walls in my basement are essentially steel-reinforced concrete + tons of earth/soil on one side (facing the excavation dugout), and structural concrete wall on the other side (facing the basement interior hallways/rooms). The solidity of the basement can actually be a disadvantage (compared to deliberately "lossy" membrane-like selective-frequency barriers) because substantially all of the bass energy/pressure is trapped with nowhere to go. But have a look at the AMROC results - there are not that many room nodes in the deep bass, except for the cluster at 55Hz, thanks to the very large room volume. Jeez, how many audiophiles have the chance to build a listening room with solid structural walls 14'5" (H), 21'8" (W), and 33'6"(L)? The installation of many 1,000s of kgs of massive activated-carbon diaphragmatic bass absorbers will effectively attenuate a significant amount of problematic bass energy above 80Hz. Therefore, the room resonances above 80Hz will be much less than predicted. Maybe I should *ADD* distance to my room dimensions to observe diminished bass amplitude?

3) "Massive carbon absorbers" - you recommended other solutions. What might they be? I'm familiar with "selectively tuned" Helmholtz resonance devices, as well as the Psi Audio AVAA, active devices which I've been using successfully in my smaller listening room. But neither seem particularly suitable in my new, much larger dedicated basement listening room.

4) Location of room modes - you recommended location-based solutions. Well, the modes appear axially, tangentially, and obliquely, EVERYWHERE! Not surprising at all, as we're dealing with persistent and powerful wavelengths exceeding 14ft. The solution is the apply correction EVERYWHERE! Well, OK, I think a door which will vent the built-up pressure to the outside (which behave like Black Holes) will likely be more effective than any barrier or membrane technology, so I may install multiple ones.

Actually, I don't want to hog up Hugh's WBF page (here), so I'll likely be starting my own page later on the topic of "QuadDiffusor's Big Dig".

 

[kodomo]

Hi Kodomo, acknowledging your comments, expressing astonishment of the assumptions I used on my (repeat: very INITIAL) calculations. I'd especially welcome friendlier comments in the sharing of your considerable experience and knowledge, if my thinking (below) is grossly out of line... many thanks in advance!

1) The Rt60 of 0.6 sec was just the default setting for the AMROC webpage! Absorptive treatments are typically non-linear (especially between 125Hz and 500Hz) and erase all energy above 1kHz so I'm assuming that generic surface area treatment calculations to lower the reverberant field decay via RT60 measurements would not be desirable nor meaningful, because the fact is that they *SUCK*! Broadband quadratic diffusors decorrelating/randomizing midbass/midrange frequencies on the wall boundary proximity points of the main L/R speakers (as well as on the sidewall first reflection points) allowing the randomized but well-balanced reverberant decay to stay "alive" longer, would be FAR more preferable, compared to absorption treatment which will aggressively and selectively suck out frequencies above vocal-range fundamentals.

Even the AMROC parameter of "critical listening distance" is based on the theoretical assumption that reflections are correlated (in-phase) to the main acoustic signal, as that's what one hears in a typical listening room. But once the indirect acoustic energy (reflections) are randomized and de-correlated, the psychoacoustical signal-to-noise ratio shoots up considerably, allowing more distance between the source and the listening position WITHOUT dilution of the realism of soundstage recreation, as the ear-brain mechanism has a much easier time processing the main L/R stereo channel signals without becoming confused with deleterious reflections. I speak from experience, as my smaller listening room has extensive treatment using P17 and P13 quadratic diffusors.

2) Theoretically, the SUBTRACTION of acoustic treatment thickness/volume would not make sense for the lowest frequencies below 60Hz because those acoustic waves are unaffected by anything but solid walls - as the walls in my basement are essentially steel-reinforced concrete + tons of earth/soil on one side (facing the excavation dugout), and structural concrete wall on the other side (facing the basement interior hallways/rooms). The solidity of the basement can actually be a disadvantage (compared to deliberately "lossy" membrane-like selective-frequency barriers) because substantially all of the bass energy/pressure is trapped with nowhere to go. But have a look at the AMROC results - there are not that many room nodes in the deep bass, except for the cluster at 55Hz, thanks to the very large room volume. Jeez, how many audiophiles have the chance to build a listening room with solid structural walls 14'5" (H), 21'8" (W), and 33'6"(L)? The installation of many 1,000s of kgs of massive activated-carbon diaphragmatic bass absorbers will effectively attenuate a significant amount of problematic bass energy above 80Hz. Therefore, the room resonances above 80Hz will be much less than predicted. Maybe I should *ADD* distance to my room dimensions to observe diminished bass amplitude?

3) "Massive carbon absorbers" - you recommended other solutions. What might they be? I'm familiar with "selectively tuned" Helmholtz resonance devices, as well as the Psi Audio AVAA, active devices which I've been using successfully in my smaller listening room. But neither seem suitable in my new, much larger dedicated basement listening room.

4) Location of room modes - you recommended location-based solutions. Well, the modes appear axially, tangentially, and obliquely, EVERYWHERE! Not surprising at all, as we're dealing with persistent and powerful wavelengths exceeding 14ft. The solution is the apply correction EVERYWHERE! Well, OK, I think a door which will vent the built-up pressure to the outside (which behave like Black Holes) will likely be more effective than any barrier or membrane technology, so I may install multiple ones.

Actually, I don't want to hog up Hugh's WBF page (here), so I'll likely be starting my own page later on the topic of "QuadDiffusor's Big Dig".

Firstly, I am sorry Hugh, as it will be a small hijackto your topic, but if a new topic opens on this, feel free to move my answer there.

Maybe there was a language problem @QuadDiffusor I did not try to sound unfriendly, on the contrary I wanted to be of help just pointing out some stuff I have read on your post. You already are an interested person, have some knowledge on the subject and it seemed you do not have a contractor yet. If you did I would not even comment so as not to be disrespectful to your designer and to their/your choices. There are so many points you have made and I will try and give my opinions on them as much as my knowledge and time allows.

1. I could not fully understand what you are trying to say here about generic absorption but if you are talking about the calculation on absorption on amroc, you have it in Sabin units. It shows how much sabin is needed for that target reverberation time, you do not have to take total m2, you can calculate according to your chosen absorbers. You also do not have to get generic products, there are many absorbers on the market with lab tested results you can refer to when planning your room.

Also rt60 may only be taken as indicative here because in your slightly larger space we are still in the domain of small room acoustics. There are series of early reflected energies and not a well mixed sound-field in a small room, no reverberations to mask these early reflections hence RT60 is not much of a relevant metric for small rooms. The reason that makes rt60 measurement less relevant also is the reason why we try and control these early reflections in a small room, be it with absorption or diffusion.

As you already know diffusion is not the same with absorption, they both have uses and can not be used interchangeably. I have used both of them in my own room, my demo room, and in many of my clients rooms. I even have a unique diffusing product on the market that actually diffuses as purely as possible without negative effects of diffraction and non linear absorption. Yes, all diffusers are also absorbing in non linear fashion, some of them much more than others depending on their shape and material.

Soundstage creation actually do not need your room or your wall reflections. Even if you have listened in an open place, the stereo recording would create the illusion of stereo panaroma. Correct treatment with absorbers (and diffusion where it is needed) does not dilute soundstage, it brings you closer to what is recorded and how engineers envisioned that soundfield. Maybe this is not the case for you but I had clients who were used to a lot of reflections and were firstly taken aback by what they heard. This happens, most people do not prefer to hear what is on the recording because that is not what they are used to. After they spent time with it some get it and could not go back to that but some can still prefer the other way, it is their own room, their own pleasure and I have no say in that. I can also not help with that as I do not know then what their target is. As we are trying to reproduce and not recreate, our aim is to have as little non linearity as possible in the whole chain of music reproduction. My philosophy for small listening rooms is based on "we are listeners and not engineers or musicians, we try to get to what engineer has decided to put on record". If I design recording/tracking rooms, concert halls what I would do is very different and is harder as there is no set goal for that. That becomes part of artistic creation. We are lucky, there is a set goal for the listening/reproduction room and that is the fidelity to signal recorded.

2. The room size is measured from solid walls. That is the room. Do not get hung up if your room is slightly out of the desired proportions area. Your room size is quite good and well proportioned and can be engineered acoustically to sound great. Also remember, below schroeder your room is a resonator and that is how you will treat it, above it, you can think of the sound like billiard balls and treat accordingly. I am writing this as you were talking about resonances over 80hz.

3. I did not say I am against carbon absorbers, I personally have not heard this treatment. I just wanted to point out that, it was not the only solution. You can have corner bass traps with appropriate dimensions and filling materials, membrane absorbers, helmholtz etc. When I read your post, I thought you were thinking you had to get a lot of these carbon absorbers. I have received tests on AVAA last week, it does work but I would prefer passive solutions if space permits.

4. Yes room modes are everywhere but certain frequencies are stronger on certain areas and that is how we can efficiently work on lessening their effects. The models show us where to treat so we are much more efficient. It would also prevent you from over treating your room.

Please do not be against any type of acoustic treatments, each has a role but each has to be used in the right amount and in the right way.

All in all, I would say good luck with your space and I hope you do not get me wrong this time. My only reason to be on this forum is to have a good, enjoyable time, learn from others experiences, share my own and make a few friends on the way.

 

[QuadDiffuser]

I substantially agree with the important points you make here. I've likely read the same material you've read (the standards). And I like where you're heading with appropriate consideration the physics and psychoacoustics, preservation of mids/highs (even modifying curve to account for a) old fart hearing loss, and b) larger room size. I really do think J. Brandt's LF baffle design is genius and highly effective, not to mention relatively cheap and easy to manage construction-wise. Not only so, but the work he and others have done on diffusion design is top notch.

Now, if we're talking about large/larger space applications, Sam Berkow has some remarkable insights (not that how he understands the science and psychoacoustic considerations are limited in application to only large spaces).

Very best wishes on your project!

Dear Tinkerphile,
Thank you so much for your kind comments! I will definitely look into, and perhaps even contact the contractors/designers which you have mentioned. Hope you don't mind if I direct a few questions to you during my journey, likely through PMs. Thank you in advance - cheers!

 

[QuadDiffuser]

Firstly, I am sorry Hugh, as it will be a small hijackto your topic, but if a new topic opens on this, feel free to move my answer there.

Maybe there was a language problem @QuadDiffusor I did not try to sound unfriendly, on the contrary I wanted to be of help just pointing out some stuff I have read on your post. You already are an interested person, have some knowledge on the subject and it seemed you do not have a contractor yet. If you did I would not even comment so as not to be disrespectful to your designer and to their/your choices. There are so many points you have made and I will try and give my opinions on them as much as my knowledge and time allows.

1. I could not fully understand what you are trying to say here about generic absorption but if you are talking about the calculation on absorption on amroc, you have it in Sabin units. It shows how much sabin is needed for that target reverberation time, you do not have to take total m2, you can calculate according to your chosen absorbers. You also do not have to get generic products, there are many absorbers on the market with lab tested results you can refer to when planning your room.

Also rt60 may only be taken as indicative here because in your slightly larger space we are still in the domain of small room acoustics. There are series of early reflected energies and not a well mixed sound-field in a small room, no reverberations to mask these early reflections hence RT60 is not much of a relevant metric for small rooms. The reason that makes rt60 measurement less relevant also is the reason why we try and control these early reflections in a small room, be it with absorption or diffusion.

As you already know diffusion is not the same with absorption, they both have uses and can not be used interchangeably. I have used both of them in my own room, my demo room, and in many of my clients rooms. I even have a unique diffusing product on the market that actually diffuses as purely as possible without negative effects of diffraction and non linear absorption. Yes, all diffusers are also absorbing in non linear fashion, some of them much more than others depending on their shape and material.

Soundstage creation actually do not need your room or your wall reflections. Even if you have listened in an open place, the stereo recording would create the illusion of stereo panaroma. Correct treatment with absorbers (and diffusion where it is needed) does not dilute soundstage, it brings you closer to what is recorded and how engineers envisioned that soundfield. Maybe this is not the case for you but I had clients who were used to a lot of reflections and were firstly taken aback by what they heard. This happens, most people do not prefer to hear what is on the recording because that is not what they are used to. After they spent time with it some get it and could not go back to that but some can still prefer the other way, it is their own room, their own pleasure and I have no say in that. I can also not help with that as I do not know then what their target is. As we are trying to reproduce and not recreate, our aim is to have as little non linearity as possible in the whole chain of music reproduction. My philosophy for small listening rooms is based on "we are listeners and not engineers or musicians, we try to get to what engineer has decided to put on record". If I design recording/tracking rooms, concert halls what I would do is very different and is harder as there is no set goal for that. That becomes part of artistic creation. We are lucky, there is a set goal for the listening/reproduction room and that is the fidelity to signal recorded.

2. The room size is measured from solid walls. That is the room. Do not get hung up if your room is slightly out of the desired proportions area. Your room size is quite good and well proportioned and can be engineered acoustically to sound great. Also remember, below schroeder your room is a resonator and that is how you will treat it, above it, you can think of the sound like billiard balls and treat accordingly. I am writing this as you were talking about resonances over 80hz.

3. I did not say I am against carbon absorbers, I personally have not heard this treatment. I just wanted to point out that, it was not the only solution. You can have corner bass traps with appropriate dimensions and filling materials, membrane absorbers, helmholtz etc. When I read your post, I thought you were thinking you had to get a lot of these carbon absorbers. I have received tests on AVAA last week, it does work but I would prefer passive solutions if space permits.

4. Yes room modes are everywhere but certain frequencies are stronger on certain areas and that is how we can efficiently work on lessening their effects. The models show us where to treat so we are much more efficient. It would also prevent you from over treating your room.

Please do not be against any type of acoustic treatments, each has a role but each has to be used in the right amount and in the right way.

All in all, I would say good luck with your space and I hope you do not get me wrong this time. My only reason to be on this forum is to have a good, enjoyable time, learn from others experiences, share my own and make a few friends on the way.

Dear Kodomo,

Thank you so much for volunteering to contribute your valuable time and knowledge, to help me with my upcoming project. I hope you don't mind pitching in more of your advice and comments, once I start my own WBF thread on "QuadDiffusor's Big Dig" or through PMs, as I don't want to hog up Hugh's thread. Please take care, and chat again soon!

 

[QuadDiffuser]

Why did you keep the rt60 at 0.6 seconds. I think somewhere around 0.3 to 0.4 seconds would be more appropriate for a listening room. Then it will show you the necessary amount of absorption needed (it will be more than above) and also the relevant schroeder frequency (it will be lower than above).

I also can not understand why you have subtracted the acoustic treatments thickness from the room. The structural walls are the actual room. You do not subtract their thickness from room size unless it is like a room within a room, even then it will be related to materials and construction of the inner shell.

There can be different approaches to lessen the acoustic non linearities of the room than walls with massive carbon absorbers too.

As you see the list of room modes on amroc page, there is also a way to see where they are located (like in that room in 3d window but more detailed) and their relative strength, so as to treat them most efficiently. Your consultant can model the room with a software utilizing comsol physics if they are capable and actually show them to you. You are dedicating a big space and will dedicate reasonable funds, this is not a small project so your consultant should be capable of at least doing that.

Hi Kodomo,

Thanks for the introduction to COMSOL! Their advanced software for modeling acoustics provide 3D heatmaps, and much more. Very cool.

Simulation Software for Analyzing Acoustics and Vibrations

Study and predict sound quality and noise reduction by modeling acoustic behavior using COMSOL Multiphysics® and the Acoustics Module. Learn more here.

www.comsol.com

 

[treitz3]

My only reason to be on this forum is to have a good, enjoyable time, learn from others experiences, share my own and make a few friends on the way.

You are not alone.

Tom

 

[Pokey77]

You are not alone.

Tom

@kodomo
I really appreciate the comment above that @treitz3 quoted. I think that is why maybe the larger majority of us are here.
Regards

 

[exupgh12]

Thank you so much for sharing your journey, along with all the valuable information, measurements, and the photos. Your post has been incredibly informative and insightful. I genuinely appreciate the effort you've put into documenting your experiences. I hope you continue to have many enjoyable hours in your room with your music setup.

 

[HughP3]

Thank you so much for sharing your journey, along with all the valuable information, measurements, and the photos. Your post has been incredibly informative and insightful. I genuinely appreciate the effort you've put into documenting your experiences. I hope you continue to have many enjoyable hours in your room with your music setup.

Thank you! Glad the thread was enjoyable to read. Best Hugh