The Perfect Room?

I am building an addition on my house, and am considering (read, begging my wife) building a dedicated listening room in the basement. Of course, it will be perfect, because all of you will guide me in this project. I'm not asking about the equipment, I'm talking about the room itself. What is the 'perfect' size, dimensions, shape, building materials, etc for a 2 channel audio room. While I'm at it, I'd better consider a multi-channel room, even though I don't currently pan to do that. Any good articles on the subject?



You might include the type of speakers you are using, type A might require a totally different setup than type B
Room dimensions are important, as are wall/ceiling/floor materials. Relative to dimensions, I’d suggest two things: First, make the room as long as possible (e.g., 32 feet is good) in order to cleanly accommodate bass notes, which have a long wave length. Second, take care to design around optimal dimensions. A post I made earlier is quoted below:

Generally, the height, length and width should not be multiples of a common factor (e.g., 8x12x16 are all multiples of 4) since this reinforces some common frequencies and provides modal gaps in other frequencies. The worst room setup is a perfect cube from that perspective.

F Alton Everest has a relatively short book on acoustics titled "Sound Studio Construction on a Budget", 1997. In that book, he recommends three good room proportions that "have stood the test of time": 1.0x1.14x1.39, 1.0x1.28x1.54, or 1.0x1.60x2.33, where the first dimension is the shortest distance (typically height) in the room. For example, an 8x12x16 room would have a ratio of 1.0x1.5x2.0.

Another often cited reference ratio is the "golden ratio" of 1.0x1.618x2.618. This arises from generating a number sequence that is based on adding the previous two numbers together to get the next and so on, starting with 1 and 2. The sequence is 1,2,3,5,8,13,21,34,55,89 and so on. When you take the ratio of the current number to the prior number, it converges on 1.618 (e.g., 89 divided by 55 is 1.618). The thought here is that the natural sequence is an ideal acoustic environment -- e.g., a great room would be 8x13x21 or 13x21x34. Since whole numbers like this aren't always possible, the multiple of the ratio also gets you there (e.g., starting with a 9 foot ceiling height, the result would be 9x14.56x23.56).

In a larger volume, "Master Handbook of Acoustics, 4th Edition ", 2001, F Alton Everest suggests a broader set of ratios from various studies that are referenced. He also indicates which of these ratios fall within a broad band of ratios called Bolt's range. The first ratio mentioned above (1.0x1.14x1.39) falls outside this range. Other ratios that fall within it and conform to other studies include 1.0x1.4x1.9, 1.0x1.5x2.5 and 1.0x1.26x1.59 (this latter ratio being 1: cubed root of 2: cubed root of 4). The golden ratio also falls outside Bolt's range (but I've found that it yields pretty good first order modal distributions, so go figure).

I'd definitely suggest reading up on things (including old threads here) before building anything since it is much easier to build it than to rebuild it.

Here’s a couple of threads that may also be of interest (search on acoustics or room to find more):
Plus, a lot has been written on outlets, dedicated lines, etc. Here are some oldies but goodies (I haven't done a recent search, but I'm sure there are many other fine threads):

The Big Four (IMHO, in no order):
1) Advice on installing dedicated outlets Jazz_nut 9-17-01

2) Dedicated curcuit question???? Krelldog 2-24-02

3) How many dedicated lines? Macm 5-31-01

4) Advice- wiring for dedicated sound room Audioken 5-28-01

Other very good ones (in no order):
1) Dedicated Circuit wire alternatives? Leoturetsky 4-11-02

2) Star Grounding Gladstone 6-1-01

3) Dedicated line vs. power conditioner Macm 5-2-01

4) URGENT HELP: Wire for dedicated lines??? Worldcup86 1-10-02

5) Isolated Ground electrical outlets??? Weiserb 3-10-02

6) Reference Ground Set-up? Fatparrot 1-20-02

7) How's to ground for the dedicated line? Worldcup86 12-28-01

see also:

8) Dedicated power circuit Joeldoss 4-14-01
The perfect room is the golden cubeaziod by Cardas which is 10Hx16Wx26L. This is supposed to eliminate any standing waves down to 32hz and allow for great speaker set-up.Good luck on your addition since it is a long process(we are just finishing ours after a 8month time frame)Dennis
I remember a Stereophile interview of George Cardas. He talked of having eliminated all the parallel surfaces in his Magnepan listening room. Struck me as one of the ultimate audio PIAs.

I suggest you also check out this site and you may find something of interest in this site.
Ozfly and others, thanks for the great info and threads. They are very much appreciated.

Here is a neat little room mode calculator that you can keep on your desktop, it's free to download and takes the math work out of the picture. Easy to read and use also.

Just click the (ModeCalc) link at the top of the page after you follow this link:

Unfortunately, no such thing as the perfect room.
call rives audio. have them help. they are really good at this.