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Discussion Starter · #1 ·
I will openly admit I don't know much about sound and the way it behaves, but ALL waves are predictable. Therefore, if someone were designing a room FROM SCRATCH, so lets say it was a freestanding unit(concrete, wood, etc), would it be possible to account for all frequencies in the room for "perfect" sound? I also know that treatments would be needed, I'm not expecting this room to just be an open box and have great sound, I mean with traps, diffusers, the materials chosen for seating, the number of seats, the golden ratio of room length, width, and height, etc. Simply could everything be accounted for so that when the room were finished it would be plug in ready? or would some of those quirks still come up? Again, just an open question.


Matt
 

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Sure you could use the best room dimensions with a room mode calculator but there really is no golden room. The trick is to not be squ, cube and as big as possible,(plus a lot of other things) but even if you have a small room you can make it sound pretty darn well if treated correctly. The following is a video showing the before and after with not only test graphs but with music playing. Note it has English subtitles.


http://www.gikacoustics.com/treated_video.html
 

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I understand this room comes as close to nirvana as you can get




What is perfect sound?


I'd say the flattest response across the designated listening positions


How do you do it?


Stuffed if I know the detail, but a combination of treatments and EQ
 

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Quote:
Originally Posted by mrgfy6 /forum/post/20868624


I will openly admit I don't know much about sound and the way it behaves, but ALL waves are predictable. Therefore, if someone were designing a room FROM SCRATCH, so lets say it was a freestanding unit(concrete, wood, etc), would it be possible to account for all frequencies in the room for "perfect" sound? I also know that treatments would be needed, I'm not expecting this room to just be an open box and have great sound, I mean with traps, diffusers, the materials chosen for seating, the number of seats, the golden ratio of room length, width, and height, etc. Simply could everything be accounted for so that when the room were finished it would be plug in ready? or would some of those quirks still come up? Again, just an open question.


Matt

Hi Matt,


There are NO golden ratios. That being said, plug and play room....hmmmmm...partially yes but mainly no. Many things can be considered on paper for the room. However, there is a big problem when you go to plug in your equipment...it won't sound incredible no matter how high end it is. In order for that great sound to come forth, we need to integrate the equipment into the room. We integrated it to a good degree from the design, but we have not married it to the room as yet. We need to calibrate the equipment to the room AND to each other once everything is installed. It is the last step to enjoying a great theater. You need some versatile equipment to do this properly and a good understanding of the physics of sound.
 

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Quote:
Originally Posted by Elill /forum/post/20869311


What is perfect sound?


I'd say the flattest response across the designated listening positions

frequency response is only one aspect of a room. eg, one "domain"


the specular response is most certainly equally weighted in terms of importance of how the room 'sounds'.


ie, the arrival of energy after the direct signal (with regards to the time-domain, with respect to the original signal), level of terminated energy, whether the returns are diffused or specular in nature, lateral arriving returns, the rate of decay of the specular energy, haas effect, etc


while there is no definition for 'perfect sound', there are many more issues to be concerned about than just the frequency domain
 

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Discussion Starter · #8 ·
Gareth, YES, that would count, however again, we didn't account for the speakers



myfipie, Shawn, that's kind of what I'm getting at. I know mostly it's NO, but I was curious if someone(like one of you fine gents, or someone who had a true understanding of how sound travels, all frequencies, etc. COULD it ALL be accounted for PRIOR to construction, yes even the behind screen(or in front of) speakers, sconces, columns, coffered or barrel or whatever cieling...CAN those be predicted? I in no way will ever be able to build this GREAT WHITE WHALE, just am a 'why' kinda person, and like to dream.


localhost, that room appears to be prepared for what 'perfection, but again, not to pick, but could they account for the chair, table, enclosures, etc. Just kinda interesting to ponder if it's possible...and to me, that room does just look COOL! nevermind fabric to cover it all, to me, why cover all of that math/calculating?!
 

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Quote:
Originally Posted by mrgfy6
myfipie, Shawn, that's kind of what I'm getting at. I know mostly it's NO, but I was curious if someone(like one of you fine gents, or someone who had a true understanding of how sound travels, all frequencies, etc. COULD it ALL be accounted for PRIOR to construction, yes even the behind screen(or in front of) speakers, sconces, columns, coffered or barrel or whatever cieling...CAN those be predicted? I in no way will ever be able to build this GREAT WHITE WHALE, just am a 'why' kinda person, and like to dream.
Mostly, yes. There will always be a few surprises due to an unaccounted thing-a-ma-jig that sticks out from the wall. Part of the problem is the prediction from an accurate model for a small room. This involves complex mathematics to say the least, and a powerful program. In part, one of the reasons few if any of these models exist is that there isn't enough dough in it.
There is lots of money to be made in large auditoriums or concert halls, but certainly not enough in the small room acoustics world. In fact small room acousticians are a bit scoffed at in the big boy acoustics world. However, as residential home theater in small rooms take a larger and larger part in the industry, some attention at research institutions is taking place. Stay tuned....we may have one...some day!
 

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Shawn - just as an aside (given the photo above) I cant find the reference, but I thought I had read somewhere that if have a room that was pretty much entirely covered in skylines or the like that the effect of them smooths out and becomes almost as if you had a bare wall i.e. less is more.


Is that right or have I been sniffing something in the shed again?
 

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Quote:
Originally Posted by Elill
Shawn - just as an aside (given the photo above) I cant find the reference, but I thought I had read somewhere that if have a room that was pretty much entirely covered in skylines or the like that the effect of them smooths out and becomes almost as if you had a bare wall i.e. less is more.


Is that right or have I been sniffing something in the shed again?
it depends on the total room design and the workable range of the diffusers on whether or not less is more.


just because you see a room coated top-to-bottom with 'diffusers' doesn't mean it is necessarily something you may want to emulate (or that it sounds good). if one were using lots of diffusers with narrow bandwidth ranges (eg, a relatively low HF cut-off point), or repeating many of the same diffuser designs into an array without applying modulation - could both create completely new problems to deal with due to improper application of diffusers.


now you'll realize why the PRDs in that photo have a 3ft well depth (and the diffractal diffuser on the ceiling extends down to 50hz IIRC).
 

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To address the original question... Given enough time, a talented engineer, a few additional modelers who simply took measurements of room furnishings and tested unknown materials for acoustic priperties, and access to a powerful computer, you could by using FEA/CFD get 'pretty close' to predicting the actual in room response as built. Naturally the more complex the room the greater the potential for variance between predicted vs measured behavior. Thus, if you had a model for a perfect room, you could get pretty darned close (given crazy resources) to building one that followed the model.


The bigger question other posters are alluding to is 'what is a perfect room response?' You have to have an ideal response in mind in order to model something that behaves 'perfectly' and then attempt to build it. What is that ideal? How strong is the indirect soundfield? What reflection delay or rather reflection free zone is ideal, if any? Do you want lateral specular reflections ala Toole/Welti or not? Diffusion? How much? RT60 goal (I know not really appropriate for small rooms but still a valid question)? Tightly clustered modes or no modes? And on and on.


This is an important line of thinking even for real, everyday theaters and listening rooms. People talk about room treatments on AVS all the time, but to what end? What is the target response that you have in mind and are attempting to achieve by making your room a certain size, positioning your speakers a certain way, or placing absorption panels here or there? What makes that target preferred to another target?


You see, we can't even come close to agreeing on what a perfect room should sound like, let alone how to then construct it, much less attempt to model it.
 

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Quote:
Originally Posted by Elill /forum/post/20872231


Shawn - just as an aside (given the photo above) I cant find the reference, but I thought I had read somewhere that if have a room that was pretty much entirely covered in skylines or the like that the effect of them smooths out and becomes almost as if you had a bare wall i.e. less is more.


Is that right or have I been sniffing something in the shed again?

The problem with small rooms is the unfortunate placement of sound reproduction devices (speakers) that often have to sit close to a boundary. Since SBIR would be considered an issue, diffusors would not be able to deal with that...at least in the conventional sense I believe you are thinking. In addition, due to the wavelengths of lower frequency waves in the speech range, interference as a result of reflection would likely also be destructive to speech frequencies and thus intelligibility. You would have to construct diffusors to deal with these wavelengths which become pretty big. Bottom line, I wouldn't do it.
 

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Quote:
Originally Posted by Bigus /forum/post/20872935


This is an important line of thinking even for real, everyday theaters and listening rooms. People talk about room treatments on AVS all the time, but to what end? What is the target response that you have in mind and are attempting to achieve by making your room a certain size, positioning your speakers a certain way, or placing absorption panels here or there? What makes that target preferred to another target?

precisely.


it's hard to give directions when someone doesn't even know what or where their final destination is.
 

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Discussion Starter · #16 ·
It appears that this is almost entirely a subjective matter, rather than objective? The two of you have a more refined idea of what "ideal" is, yet they could each be different, and each be different to what my untrained ear would hear as "best", right? Also, all of those other factors would account for something in the design, not just a flat response at reference level from ~2-15k hz...This was more of a theological question than one that I thought would elicit an exacting result. Thanks guys, and this doesn't make me feel so bad in my researching this new and exciting hobby...what sounds good to me is what really matters, after all, it's my money I'm spending! haha


Thanks again!
 

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Yes and no to your conclusion. There are objective aspects to the room...several in fact. In essence, we are indeed trying to elicit a flat response in the frequency domain while still trying to maintain some decay in the time domain. Once we get the flat response, we can then change the frequency response to the tastes of the client. We fix it first using science, then shape it to what we want cuz we can!
 
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