Setting-Up Speakers In A Rectangular Room
 
The following article was written some years ago by George Cardas of Cardas Cables. 

Here’s a link:  <http://www.cardas.com/room_setup_main.php> where you can see some diagrams.

Very precise speaker placement can open up a whole new dimension in listening, so I will outline the system that is becoming the standard of the industry. The Audio Engineering Society’s (AES) standard listening room is a model of the maths used in this system and is the room used for illustration. This method will work with any panel or box speaker, in any reasonably sized rectangular room. You may find that you have already positioned your speakers this way by ear.

The AES standard listening room is a Golden Cuboid 10’ x 16’ x 26’. Its dimensions progress in the Golden Ratio or Fibonacci sequence (5-8-13-21-34…). The three major nodes created within the listening space are indivisible, and therefore will null rather than beat. The maths used to create this perfect listening space can also be applied to speaker placement within any listening space.

The key to this formula is the ratio Phi (0.6180339887… to 1 or 1 to 1.6180339887). The three major room nodes are created by the distances: ceiling to floor, side wall to side wall and front wall to back wall.

To determine initial speaker placement, multiply ceiling height by 0.618 (10’ x 0.618 = 6.18’) to determine the distance from the rear wall to the centre of the woofer or the acoustic enter of a panel.

Then multiply the room width by 0.276 (width divided by 18 x 5) to determine the distance from the sidewall to the centre of the speaker. (16’ divided by 18 x 5 = 4.4’). At this point place the speakers on tiptoes, one in front two in the back. If the speakers are not very heavy, I suggest placing a bag of lead shot on top of them. Play the system for a few hours and then fine-tune their position. Usually speakers will not have to be moved more than one inch. Don’t forget to damp first reflection points.
 
George Cardas