Quote:
Originally Posted by Jeffrey Hedback  right! Absolute killer for clients (referring to 75% back), the second order axial mode. In the 20' length example: 56Hz null or essentially the low A on bass guitar. Case again for proper bass tapping.
Back to original post: monitor placement in your size room has to be a compromise between how you excite modes (38% back, 60 degree triangulation) and imaging. Like Frank mentioned, closer than 4' and you're not going to get stereo field. You may get best results by breaking convention. Beyond proper room treatments, the accuracy of your monitoring system is ultimately going to be greatly influenced by speakers themselves: are they ported? What is the off-axis response? Edge diffraction...etc |
Jeff,
Actually, what Ethan and I were referring to was not the 2nd order axial mode, whose null is, as you correctly state, located 75% from each boundary. We were referring to the 3/4 wavelength null caused by the distance from the listener to the back wall, which is not a modal null, but a boundary interference null. The most commonly referenced ones are at 1/4 wavelength, but they exist (although a bit toned down by distance) at 3/4 wavelength as well, a fact that becomes obvious as you get far enough from the boundary that the 1/4 wavelength null drops into the sub-audible range. But I'm sure you already know this stuff. Just wanted to clear up the confusion - I should have stated it more clearly to begin with.
-Wes