Towards a Better Sounding System – Part 1
The room that a sound system is going to be in, is the most important factor in the way it will sound. Room acoustics will define the way a system sounds. The problem with most rooms is that they can easily overload or too reverberant. If a room overloads the sound turns to mush. If the room is too reverberant the sound will become confused. With live music the rooms are usually bigger and the reflected sound put off in time, so your ears and brain can recognize it as a separate sound. If the reflection is too close in time, it will simply blur the sound. One of the biggest problems in room acoustics is standing waves. This happens when waves are built in the edges of the room.
There are two main means of controlling sound in a room, absorption and diffraction. Absorption uses material to absorb some of the sound. The higher the frequency, the easier it is to absorb. The bass frequencies are very hard to absorb and are a major problem. Diffraction breaks up sound waves by presenting an uneven surface to break up the reflected sound waves. Absorptive material can include foam, egg crate foam, fiberglass, rugs, drapes, stuffed furniture, tube traps and corner tunes. Even more mate acceptable is the use of artificial tall thick foliage plants in corners and behind and between speakers. There used to be a stereo store in Portland that had a forest of artificial plants behind his speakers. The room sounded very good. Commercial room treatments can be quite expensive. Tube trap like devices can be made from commercial pipe insulation, wood rounds and cloth, at big savings. Will these traps be as good as the commercial ones, probably not? There are instructions on the internet describing how to make them. There is also room tuning devices, from Shakti Innovations, called Sonic Hallographs. These work very well. Then there are mpingo discs. At $90 each, they are expensive. You can make mpingo squares by going to an exotic wood store and getting some scrap mpingo (black African wood) wood and cutting them into 1.5 inch squares. Synergistic Research has a big line up of room treatment devices that seem interesting, but I have not heard them. They are also quite expensive.
Diffraction can happen when sound waves hit a hard surface that is not even in height, the more height difference the better. Book cases and shelving, with gaps in their surface, are the most commonly found diffractors in rooms. On the internet, I have seen large wood panels, with slots of varies highs cut into them. I have also seen wood panels with different levels of wood sticking out. On Utube, there are instructions on how to build a diffraction panel using 2″ X 2” wood, cut to various lengths. I have also seen rooms with all the walls covered with perpendicular wood projections. Care must be taken in treating a room. If there is not enough treatment, your sound will suffer. If there is too much treatment, the room will sound dead and unnatural. If you walk into the center of room you want to use. Clap your hands hard! If you hear an echo or muffled sound, you have a problem.
In my 20 X 21 foot room, is heavily treated. I use 8 tube traps, 4 corner tunes, 3 foam panels, 6 mpingo squares and 3 Sonic Hallographs. I have wall to wall carpet plus an area rug between speakers and listening position. My ceiling is acoustic panels. My back wall is a 16ft. wide by 6 ft. high cd and DVD storage rack. My room is somewhat ugly, but I am lucky enough to have a dedicated room. My room is of zero mate acceptance, Ugly but sounds very good. Commercial room treatment meant for audio is very expensive,
If you can’t at least somewhat acoustically treat your listening room, spending lots of money on your stereo is a waste of money. I have heard a system that was probably around $200,000 in a large untreated room. The sound was really bad, even though with the very high end equipment, it should have sounded great. I have also heard another system in a smallish room that was untreated. The cost of the system was well over $150,000. The system had very high end audiophile equipment. The system sounded fairly good at lower volumes, but totally turned to mush as the volume went up.
Part Two of this series will be: “Selecting and Setting Up The Equipment”