Hi All,
Here is a newsletter I wrote many years ago reflecting John Dunlavys ideas on room setup:
Gee's, yet another room set-up for optimizing your sound room for the best possible performance.
This one suggests that you consider using the short dimension of your listening room rather than the more popular long dimension.
It must be stressed that the whole point of this and the other room set-ups I have mentioned is to try and reduce the room colorations from affecting your listening environment and distracting from the fidelity of the recording. Most people do not realize how critical this "room-speaker interface" really is in attaining quality sound. The listening room is the final component in any audio system.
One of the advantages obtained with this "long dimension" arrangement is that it allows you to place the loudspeakers fairly wide apart providing a more realistic soundstage size. (Most recordings are made with the listener at the apex of an equilateral triangle.) Also, with this technique the loudspeakers are still a long way from the side walls so the early side wall reflections are lengthened (a good thing) in time. A further advantage is the reduction of comb-filtering effects present in the room. Combfiltering is defined as two sound waves interfering, one delayed in time relative to the other. Putting the listening chair near a boundary assists in reducing the comb-filter effects at low frequencies. There are still comb-filtering effects going on but they are generally above 4 thousand cycles (which is less bothersome) rather than between 80 and 500 cycles which occur if your seated out in the room.
When you place the loudspeakers make sure the distance from the rear wall is different than the distance from the side wall. Example: if your 2 feet from the back wall be about 3 feet from the side walls, if 3 feet from the back wall then 4 feet from the side wall, etc. This helps reduce the proximity effect of the two surfaces from affecting the speaker response at low frequencies.
You can have as much as a 6dB rise at some frequencies if these distances are identical. and as much as a 9dB rise if a third sure (floor) is also within this same distance.
There is one final advantage of this type of set-up which is less obvious. As we move towards multi-channel sound and the need to accommodate 5 loudspeakers equal distance from the listening position using the long dimension concept more easily accommodates the rear channels distance requirement.
Other factors to consider are: do not place any acoustic absorption materials, on the rear wall behind your head and sit as close as possible to the rear wall (6 inches to a foot). Spread the speakers at least as far apart as you are from them, (if your 9 feet away spread the speakers at least 9 feet apart) and angle them in so they are pointing directly at you. Place acoustic absorption material in the front corners of the room and some on the center wall between the speakers if required. Some acoustic absorption in the rear corners of the room can also help.
So hey, give it a try and see if the results warrant a total flip-flop of all the furniture, pictures and rugs in your listening room.
