Whats are the different theories on room acoustics to create a great sounding room?

KlausR.

Well-Known Member
Dec 13, 2010
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Yes, I am describing rooms with too much reverberation and reflections because that is what, anecdotally, I have found to be common.

One treatment that is broadband and highly effective, yet doesn't suffer from low WAF is



And no, it's not the rug :cool:
Klaus
 

igufi

Well-Known Member
Apr 12, 2011
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Finland
I'm sorry for jumping in here in the middle of the discussion but I've had this stupid question nagging me for a while now regarding room acoustics and audio playback:

I know that listening to a mono or stereo music in a anechoic chamber sounds terrible. But why? If the recording was from a live event and the mics captured not just the music but also the echoes of the room/space that the musicians were in, why isn't that enough to remove the muffled/claustrophobic feeling you get when listening in a anec. chamber? Would it be possible to create a recording with enough echos and other spatial clues to fix this? Why don't I get the same effect when listening to headphones? Is it because of the space in my ear canal that acts as the "room", providing the needed echoes etc?
 

Nyal Mellor

Industry Expert
Jul 14, 2010
590
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SF Bay Area, CA, USA
One treatment that is broadband and highly effective, yet doesn't suffer from low WAF is



And no, it's not the rug :cool:
Klaus

Couch, but not if it is leather..
 

Nyal Mellor

Industry Expert
Jul 14, 2010
590
4
330
SF Bay Area, CA, USA
Nyal,



You can measure different decay times for different frequencies, and using 3" absorbers still leaves the decay times unbalanced. The question is, is an unbalanced RT60 really disturbing given the fact that the sound field in the case of directional loudspeakers in a small room is highly directional?




According to research by Bech with speech and noise it is the floor reflection that has the greatest impact. According to Guski the ceiling reflection may cause confusion when being the only reflection remaining. Was the ceiling reflection the only or merely one of several reflections to be treated? You say that the back wall reflection does not do anything beneficial, but is it disturbing? With music Wrightson found that a rear wall reflection did not change the image width significantly.

Since off-axis response is responsible for how the reflection will look like spectrally it would be interesting to see how the off-axis responses of the systems you’ve treated looked like. The cases you are mentioning may have presented reasons that made reflection treatment have beneficial effects. Were the systems 2-channel or multi-channel? I’ve prepared a 23 page literature review (88 references) on this issue of early reflections (2-channel only), if interested, send me a note.


Klaus

I guess the question is one of balance of the late arriving sounds relative to the direct sound and early reflections. My belief is that is should be spectrally balanced. Varying RT60 across the spectrum is normally a symptom of uneven absorption in the room. This will tend to disrupt the spectral balance of late arriving sounds. I think the power response should also be similar to the nearfield response. Of course this is theory, we do not have enough listening tests scientifically completed to validate this.

I agree that treatment of first reflection points is dependent on speaker directionality. Line source type speakers often do not require ceiling treatment, likewise speakers with well behaved off axis response horizontallly may not require side wall treatment. The type of speaker and its radiation pattern should be taken into account during acoustic design.
 

P.C.

Well-Known Member
May 30, 2010
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1,561
Vancouver, WA, USA
Ok I'm probably going to come across as a complete idiot with this question,I also hope I'm asking it on the right thread . But having lived with my stereo audio only system in my family living room for ever I've finally decided to move my audio system into our finished but unfurnished basement and make it my own private man cave. . Mostly due to funds (the lack of) my question is can a room be properly treated by not using any (or as little as is necessary) custom made and expensive treatments. But mainly with various home furnishings. Sofas, rugs, wall hangings plants etc anything really that could approximate the technically correct acoustical made product.
If in principle the answers yes. My idea/plan.was to firstly employ a local? acoustical expert and presumable one who wan't only selling his specific products! to come and measure and test my basement and come up with plans to make it work acoustical using only or mainly stuff I either have ( for example "you should put your 4000+ cds"( which live in wall mounted open framed woodwn cases) on this wall floor to ceiling bookcase should go their , get a massive soft sofary sectional thingy and plop it here etc etc.
As its my man cave I want it to look a rather unkept and cosy rather than a well organized and a little sterile audio room but still for it to 'measure' pretty well to helpget the most of my system ( which is actually quiet good I think) Part of the fun would then be trying to source the' right ' type/size of object needed used cheaply and locally via Craigslist etc.
Does any of that make sense and if so who should I contact /employ? Thanks.
 

Bruce B

WBF Founding Member, Pro Audio Production Member
Apr 25, 2010
7,006
512
1,740
Snohomish, WA
www.pugetsoundstudios.com
Does any of that make sense and if so who should I contact /employ? Thanks.

Howdy neighbor!! I don't know of anyone here in the Pacific NW. I had to go down south.

Most anyone could measure your room. It's the interpetation and execution that you pay for. The biggest sticking point would be symmetry.
 

fas42

Addicted To Best
Jan 8, 2011
3,973
3
0
NSW Australia
I know that listening to a mono or stereo music in a anechoic chamber sounds terrible. But why? If the recording was from a live event and the mics captured not just the music but also the echoes of the room/space that the musicians were in, why isn't that enough to remove the muffled/claustrophobic feeling you get when listening in a anec. chamber? Would it be possible to create a recording with enough echos and other spatial clues to fix this? Why don't I get the same effect when listening to headphones? Is it because of the space in my ear canal that acts as the "room", providing the needed echoes etc?
This is largely guesswork from me, but I would suggest that the human mind is conditioned to expect echoes in a closed space; it "knows" what it should hear, from the level of sound and environment, and when it doesn't get that it feels wrong, you are disturbed, not comfortable with the sound. I've been in audio enthusiast's homes that have been heavily treated, are very dead and I quickly lose interest in staying in that space.

With headphones I guess the sound is still bouncing around enough in the space between your ears and the physical bits of the headphones to reassure the ear/brain that it is not completely in a foreign environment. The hearing mechanism is very clever in adapting to situations, but sometimes it just doesn't get enough information to work out what things should sound like, and then you don't like what you hear.

Frank
 

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