Posted by Sam P. on February 28, 2002 at 07:40:21

In Reply to: measurement system DOES suk posted by Sam P. on February 28, 2002 at 06:23:20:

After drawing a side view of my mike and driver positions, it seems the dip is really a diffraction/cancellation situation. The mike was about 39 inches high - halfway between the centerline of the 511 and the UPPER woof, which made the path length from each of the two woofs to the mike differ by approx. 7 inches, one-half wavelength at 960 Hz. So it was science, not room ghosts or coil values that were at play after all. Probably would not have been there at a different distance/height...also, above 500 Hz, as the dispersion of the lower woof was narrowing, less energy would have reached the mike that was about 30 degrees away from the lower woofs axis. Sand, sand, sand...