Home Speaker Asylum

General speaker questions for audio and home theater.

Oh, the rule of thirds or fifths is simply a starting position for speaker placement, instructions follow.

The “rule of thirds” has been around for decades I ran across it back in the 1980s.

Step 1- When first setting up speakers in a room begin by placing them 1/3 of the length of the room out from the rear wall and 1/3 of the width of the room out from the side walls or you can use a 1/5 room length and width ratio. This odd fraction placement gives a smooth distribution to the excitation of the rooms standing waves in the bass frequencies. Then start moving the speakers around a few inches forward or backward from the rear wall until you get the smoothest bass response at your preferred listening position.

Step 2 - Once you have fixed the distance from the rear wall start adjusting the speakers distance away from the side walls (be sure to keep the same fixed distance from the rear wall as you adjust the distance from the side walls) till you get the best stereo image in the center. If a speaker pair has too great a separation between left and right speakers then there is not sufficient centerfill to the stereo image and if the speakers are too close then you lose stereo separation and get too much of a monophonic sound. Somewhere between these extremes is a sweet spot for stereo soundstaging.

Step 3 - After you have the distances from the rear and side walls fixed then proceed to adjusting the toe-in of the speakers until you have the best balance between midrange and high frequency response.

Step 4 - Small adjustments of position, angle and tilt can now be made to lock-in the best stereo image.

PS. With very heavy speakers a shortcut to the above can be tried. First position one speaker at your listening position and then move yourself around in the area where the speakers are to be placed until you hear the best balance to the sound; do this first for one channel then for the other, mark these spots with some tape then move the speakers to those marked locations and listen. This will still require some final adjustment to the speakers placement but it is a good rough start.

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  • Oh, the rule of thirds or fifths is simply a starting position for speaker placement, instructions follow. - cfb 12:14:06 02/05/10 (1)


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