Introduction to Room Acoustics

Start With the Room

Rigid Walls

Wisdom Audio believes in equalization. Assume for a moment that you had a “perfect” loudspeaker: as soon as you place it in your room, its perfection is gone. In fact, even good rooms often introduce deviations of 20 dB to the re- sponse of the system.

It seems strange to us to worry about tenths-of-a-decibel differences between one component and another when there are 10-20 dB problems right there in the room with you.

At the same time, room equalization is not a panacea. It does not solve all prob- lems. In fact, and somewhat paradoxically, EQ works best when it has the least to do. It is best used as the “finishing touch” on an otherwise good system. Un- fortunately, most people do not understand that the most important component in their system is their room.

This manual does not have the space for a full description of everything that goes into creating excellent room acoustics; doing so would require a textbook of several hundred pages. Instead, we will give you some ideas, and some refer- ences to pursue should you want to learn more.

There are many myths floating around pertaining to what a “good room” should be like. One of the most common is that it should have non-parallel walls. Without going into the details, we recommend staying with rectangular rooms whose dimensions do not share common divisors.

Thus a room with dimensions of 8' by 16' by 20' would be quite poor (since the dimensions are all divisible by a length of 4', and 16 is also multiple of 8). By contrast, a room whose dimensions are 9' by 16' by 29' would be much better, since none of the dimensions are mathematically related to one another.

There are infinite variations on this idea. If you have the flexibility to choose (or modify) your room dimensions to avoid such problems, do so. Either way, our room correction will be a big help.

Another myth that should be dispelled is the notion that the walls (and ceiling and floor) of the room should be extremely rigid in order to reproduce good bass. Rigid, inflexible walls reflect energy extremely well; thus you will keep more of the bass energy in the room. This much is true. However, those rigid walls will only increase the amplitude of the standing waves that your room naturally supports. In simple terms, you will have more bass, but it will also be more irregular, with larger peaks and valleys in the response.

Walls that flex a bit (but do not rattle) are much better. Coincidentally, tradition- al American residential construction standards (sheet rock on wooden studs) are not a bad place to start. You can do better still with professional help, but studs and sheet rock are better than poured concrete. (If your listening room is in the basement, a false wall can easily be built in front of the concrete. You probably need something like this for insulation and aesthetics anyway.)

The ultimate in dedicated listening room construction involves the design and construction of floating walls, ceiling and floor. This approach yields the added