Custom dedicated audio room owners unite!

[kodomo]

My prior room where I had a great even response, with very good homogenous decay. Only detrimental room effect (which was minimized via treatments) was caused by side reflections.



My current room has a low ceiling and is a smaller space. I have good response,, better side reflections but a little more uneven bass, generally close to what I had in my prior room with good homogenous decay.
Room dimensions: 7.66m x 5.78m x 2.5m
Room proportions: 3.06:2.31:1




The demo room I am building for my speaker brand. Much higher ceiling, wider room, good proportions. Only treatments left to do are ceiling panels and the afghan hand weaved carpet.
Room dimensions: 7m x 5.70m x 4.15m
Room proportions: 1.66:1.31:1

 

[marty]

That is a beautiful room with the promise of truly great sound. Congratulations.

 

[dminches]

That is a beautiful room with the promise of truly great sound. Congratulations.

Post some pictures of your room.

 

[Ron Resnick]

I am afraid I have a different view than the consensus here. I may be wrong, but this is based on my observations, experience and a bit of logic. I implemented myself my views here, so I did eat my own cooking.

I think that whatever sonic equation professional acousicians are solving for usually, if not always, results in over-damped, slightly lifeless listening rooms.

It doesn't make sense to me to outfit fully with acoustic treatment a dedicated listening room without hearing and measuring how one's actual loudspeaker system in the context of one's actual audio system actually sounds subjectively and performs objectively in that room. Full acoustic treatment in advance makes even less sense to me if one does not know which loudspeakers one will be installing in the room.

My professional acoustician is a wonderful, experienced, extremely knowledgeable and talented acoustician, and I appreciated her approximately seven recommendations. I think I adopted three of them.

As I adjust my room to my new system and acoustic problems are revealed from the actual system physically in the room and playing music in the room, I still believe that baking irreversibly into the cake vastly more absorption in the walls and on the floor and in the ceiling as prescribed by my acoustician would have been a sonic mistake. Once acoustic energy is absorbed and removed from the listening room that energy will never come back.

I think it makes sense to build solid, rigid and structurally sound walls and floor and ceiling. I think natural brick and natural hardwood are good interior wall materials. But I am glad I did not build into the walls, floor and ceiling, and bake irreversibly into the cake, all of the absorption which was recommended to me by my professional acoustician.

My only other thought is that high ceilings seem to be of greater subjective sonic and musical realism value than room dimension calculators suggest.

 

[dminches]

Ron, I am not completely sure what you are saying but I would think that any acoustic engineer would make decisions about a room based on measurements of the equipment in that room. That’s what my engineer (Jeff Hedback) did. Everything done was in the context of the actual room and actual equipment.

 

[Ron Resnick]

Ron, I am not completely sure what you are saying but I would think that any acoustic engineer would make decisions about a room based on measurements of the equipment in that room. That’s what my engineer (Jeff Hedback) did. Everything done was in the context of the actual room and actual equipment.

This protocol makes much more sense to me than fully outfitting with acoustic treatment an empty room based purely on measurements without having the actual loudspeakers and equipment in the room and solving acoustically for that equipment in the room.

 

[Steve williams]

This protocol makes much more sense to me than fully outfitting with acoustic treatment an empty room based purely on measurements without having the actual loudspeakers and equipment in the room and solving acoustically for that equipment in the room.

out of fairness Ron, Bonnie made those suggestions well before you were even under construction. Your comments about putting in wall absorption without measurements makes of overdamping which I agree. However when I commissioned Bonnie she was at my house every week, taking measurements and making recommendations on the fly. I'm sure she would have done the same for you if she were involved in the build out. She was at my home one day taking measurements and then went back to New York to do the room mapping for which she is renown. She called me a few days later and told me I had to move my racks six inches closer to the rear wall to eliminate room nodes. Much to my amazement that 6" shift made a dramatic difference in my room

FWIW my room is 20 x 15 x 9

I too use quiet rock on top of standard sheet rock and the seams are midway between the seams of the underlying sheetrock. I also use a special glue at the corners that prevent movement. Under my carpet she has an OEM product that effectively turned my floor into a bass trap as her biggest concern was using the large Wilson's in the room. Her solution to that was to use wall drapes that have a reverse horizontal pleat in a ratio IIRC of 2.5:1. This too minimized room nodes. Finally , in my ceiling she used 8 high hats rather than cans. These extended through the attic floor. On top of these she placed another of her OEM products called "high hat mufflers". Essentially each one of these was tuned as a Helmholtz resonator to further eliminate room nodes. When I undertook this project all of my friends bet against my outcome and success. To me it was choice that I had to make as I was not going to sell my speakers or electronics and I knew that this was a challenge for Bonnie. She evaluated the space before any construction was done. Her comments to me was that not only would the room sound good but she promised me it would sound better than my old room. I was very pleased with the outcome .

 

[Ron Resnick]

out of fairness Ron, Bonnie made those suggestions well before you were even under construction. Your comments about putting in wall absorption without measurements makes of overdamping which I agree.

Please recall that I was never "under construction" as Bonnie and I were working with an existing room. Please recall it was never a ground-up, clean sheet situation.

Bonnie's recommendations all were based on the measurements she took in the existing room.

Frankly, now that the system is in the room snd playing, and now that we can make accurate measurements of the actual frequency response anomalies, it might very well make sense for Bonnie to return to the room and to identify, target and surgically address the specific room anomalies which we now can measure and which we now know exist.

At this point I would like to ask Bonnie if she thinks that very narrow band SMT Vari-Tune Helmholtz resonators targeting specifically 60Hz and functioning as sharp as possible notch filters would mitigate the 60Hz room boom, and if Vicoustic Multifuser Wood 36 panels targeting 2kHz to 5kHz would mitigate the 2kHz to 5kHz plateau peak.

 

[sbnx]

I think that whatever sonic equation professional acousicians are solving for usually, if not always, results in over-damped, slightly lifeless listening rooms.

I think it makes sense to build solid, rigid and structurally sound walls and floor and ceiling. I think natural brick and natural hardwood are good interior wall materials. But I am glad I did not build into the walls, floor and ceiling, and bake irreversibly into the cake, all of the absorption which was recommended to me by my professional acoustician.

My only other thought is that high ceilings seem to be of greater subjective sonic and musical realism value than room dimension calculators suggest.

I have to agree with Ron on this. I followed the acoustician and my room is pretty highly damped. I have had an RT60 below 0.2 in my room at times. I have also had it up around 0.42. I find the goldilocks RT60 to be about 0.35 for me. As I mentioned in my first post in this thread if I were to do this again I would not build much of anything into the room. Perhaps the only exception being large floor to ceiling bass traps in the back corners. Everything else would be panels that can be moved around / adjusted.

I also agree that a high ceiling offers a lot. It obviously contributes to the Volume of the room which directly related to the RT60. This also an area where some treatment could be applied (e.g. soffit) that is out of the way.

I am also against splayed walls and angles. These things make getting speaker placement dialed in waaaay more challenging. The reason for this is (for example) as you pull the speaker forward and you are finding the sound is getting better and better and then BANG everything goes to sh*t. The reason for this is that the refection is folloing a surface along an angle as the speaker moves forward and then suddenly the angle changes and thus the sound at the MLP changes drastically and you are starting all over.

The suspended drywall on clips and furring channel has plusses and minuses. I think I prefer the plus side which is that when you play deep bass the room doesn't rattle and neither does the rest of the house.

 

[Steve williams]

My RT60 is 0.40

Don't you find when the RT60 is less than 0.2 that the sound is quite dry and analytic

 

[microstrip]

I am afraid I have a different view than the consensus here. I may be wrong, but this is based on my observations, experience and a bit of logic. I implemented myself my views here, so I did eat my own cooking.

I think that whatever sonic equation professional acousicians are solving for usually, if not always, results in over-damped, slightly lifeless listening rooms.

It doesn't make sense to me to outfit fully with acoustic treatment a dedicated listening room without hearing and measuring how one's actual loudspeaker system in the context of one's actual audio system actually sounds subjectively and performs objectively in that room. Full acoustic treatment in advance makes even less sense to me if one does not know which loudspeakers one will be installing in the room.

My professional acoustician is a wonderful, experienced, extremely knowledgeable and talented acoustician, and I appreciated her approximately seven recommendations. I think I adopted three of them.

As I adjust my room to my new system and acoustic problems are revealed from the actual system physically in the room and playing music in the room, I still believe that baking irreversibly into the cake vastly more absorption in the walls and on the floor and in the ceiling as prescribed by my acoustician would have been a sonic mistake. Once acoustic energy is absorbed and removed from the listening room that energy will never come back.

I think it makes sense to build solid, rigid and structurally sound walls and floor and ceiling. I think natural brick and natural hardwood are good interior wall materials. But I am glad I did not build into the walls, floor and ceiling, and bake irreversibly into the cake, all of the absorption which was recommended to me by my professional acoustician.

My only other thought is that high ceilings seem to be of greater subjective sonic and musical realism value than room dimension calculators suggest.

Curious that you disagree on one the most important recommendations of the acoustician, considering it was a sonic mistake, only keeping a few others. It is usually assumed that expert designed acoustic treatment is a extremely balanced integrated system, but can we know what were the three recommendations you kept and the three more you abandoned?

 

[microstrip]

I have to agree with Ron on this. I followed the acoustician and my room is pretty highly damped. I have had an RT60 below 0.2 in my room at times. I have also had it up around 0.42. I find the goldilocks RT60 to be about 0.35 for me. As I mentioned in my first post in this thread if I were to do this again I would not build much of anything into the room. Perhaps the only exception being large floor to ceiling bass traps in the back corners. Everything else would be panels that can be moved around / adjusted.

I also agree that a high ceiling offers a lot. It obviously contributes to the Volume of the room which directly related to the RT60. This also an area where some treatment could be applied (e.g. soffit) that is out of the way.

I am also against splayed walls and angles. These things make getting speaker placement dialed in waaaay more challenging. The reason for this is (for example) as you pull the speaker forward and you are finding the sound is getting better and better and then BANG everything goes to sh*t. The reason for this is that the refection is folloing a surface along an angle as the speaker moves forward and then suddenly the angle changes and thus the sound at the MLP changes drastically and you are starting all over.

The suspended drywall on clips and furring channel has plusses and minuses. I think I prefer the plus side which is that when you play deep bass the room doesn't rattle and neither does the rest of the house.

Do you have current RT60 figures versus frequency?

 

[pjwd]

My RT60 is 0.40

Don't you find when the RT60 is less than 0.2 that the sound is quite dry and analytic

Steve as I understand it RT60 is not strictly a correct measurement for small rooms although still possibly a usefull guide.
The areas to focus on in our size rooms are early reflections and csd or waterfall plot generated by a ballon pop or spherical speaker.
I do agree that if you select a acoustic consultant you should go all in on their recomendations as they are generally all interelated. Using someone who shares your goals and developing a wriiten brief are the keys ... prettymuch like any consultant
Phil

 

[Steve williams]

I agree with everything you say.

 

[kodomo]

Decay follows frequency response and also room size related. As someone who works as an acoustician, I also prefer 0.35s to 0.5s and try to achieve that in the rooms that I work with. 0.2s is too short but more important thing is having homogenous decay from 40hz+ and have the response even. I attach a rt60 graph from my room. It is indicative, actually the room sizes are small to have meaningful rt60 graphs.

My old room

 

[sbo6]

My RT60 is 0.40

Don't you find when the RT60 is less than 0.2 that the sound is quite dry and analytic

I have found through much trial and error and many measurements correlating RT60 to listening that .3 sounds right to my ears. Not too dead, not too vibrant / muddy. FWIW, it took me a long time to get to this RT60 in my modest sized room.

 

[Ron Resnick]

Curious that you disagree on one the most important recommendations of the acoustician, considering it was a sonic mistake, only keeping a few others. It is usually assumed that expert designed acoustic treatment is a extremely balanced integrated system, but can we know what were the three recommendations you kept and the three more you abandoned?

What was a sonic mistake?

Adopted: blue jeans insulation in furred-out front wall
Adopted: blue jeans insulation in soffit cavities
Adopted: acoustic-thermal insulation in side-walls

Rejected: vinyl sheeting in front wall
Rejected: vinyl sheeting in side walls
Rejected: Lumitex under floor carpet
Rejected: Vibramat (with vinyl layer) under floor carpet
Rejected: Lumitex lined drapes on side walls and rear wall

 

[pjwd]

Decay follows frequency response and also room size related. As someone who works as an acoustician, I also prefer 0.35s to 0.5s and try to achieve that in the rooms that I work with. 0.2s is too short but more important thing is having homogenous decay from 40hz+ and have the response even. I attach a rt60 graph from my room. It is indicative, actually the room sizes are small to have meaningful rt60 graphs.

My old room
View attachment 104622

Thats pretty impressive! Do you work on many listening rooms or larger projects
I recall dolby recomended a descending RT60 with fr rise going down to 3.4 or similar .. I presume that is for larger spaces..do you have a view on that
Cheers
Phil

 

[sjs]

Well like anything else hiring someone that does not design home hifi listening rooms and has not done this many times would be a huge red flag. Recording studios, concert halls, corporate rooms, and home theaters are NOT the same thing!

I very much agree with this.

I know a lot of acousticians, and only a very tiny number are into hi end two channel stereo in my experience. A small number have good experience of room acoustic design, rather than building noise control or environmental noise, and of them it will be typically not in domestic situations. Where it is, it will more likely be home theatres, which are generally over damped and dead spaces.

My take on a good room for stereo is to get proportions and speaker/listener locations to minimise room modes, then good LF absorption, a nice amount of midrange RT, and a good amount of diffusion. More of a mini concert hall type approach, than an overly controlled dead space.

However, I am also aware that this is influenced by my taste in preproduction, so as usual ymmv.

 

[kodomo]

Thats pretty impressive! Do you work on many listening rooms or larger projects
I recall dolby recomended a descending RT60 with fr rise going down to 3.4 or similar .. I presume that is for larger spaces..do you have a view on that
Cheers
Phil

I work on quite a few projects and I also have my own diffuser product which can be seen on the back walls and doors of the demo room I have been building.

My interest lies with small listening spaces and let me tell you, it is not a popular one. Besides the ones who are working on various scientific experiments, most acousticians deal with noise or voice intelligibility. A very limited number of them work with concert halls and Some work for recording studio designs. Studio design has two faces (recording and mixing) and two separate goals. The mixing room goals and applications are very similar to our listening room goals in a way that the goals are fixed and we know what to shoot for. For concert halls or recording spaces there are some broad rules but no set goals, as recording and creating a sound is an art form in itself with no single right answers.

Back to our listening spaces; Contrary to studio mixing spaces we have many more problems. A domestic listening room adds multiple complexities because of set room shapes, furnitures, variety of speakers that are not as easy to work with as studio monitors, not being able to make all needed treatment because of decor and lastly the clients tend to pick and choose. I am also sorry to say the audiophiles are a hard breed to work with. Sometimes it becomes frustrating.

The descending rt60 is right, like the frequency response curve, mostly even but with a slight rise at LF. It will be like that if the treatment is rightly done, it will follow the speakers response. If you have strong LF but straight rt60 that means you are dampening lf more than hf. So, a good fr and a good rt60 will actually look similar.

The rt60 I showed was flat because the response was flat. I was adjusting my speakers and room. I attach the corresponding fr response of that rt60 so you can see. This is not how I listen, I prefer a slight rise on LF but not as much as Harman target curve but closer to Toole's preferred response curve.