Lamm "L2" Triple Boundary PZM Array

After I finished my PZM capsule "pick-ups," it only took me an half hour to build the Lamm L2 unit out of 1/4" think foam core. Two 20" X30" sheets were sufficient. The slowest part was figuring out the layout for the base. The L2 definitely produces a curious stereo image. Localization is quite good. As described in the Crown Application Guide, mounting the DIY PZM capsules on a boundary smaller than 4 ft. by 4 ft. does attenuate some low frequencies. You can take a listen/look at some files and sonograms I assembled here. Rob D.

Studio Stereo Localization Test Observation & Question For Curt

Hi Curt--
Putting aside the double boundary PZM fixture (which is interesting and I'll take up in another post), some of us guessed that a rig with an angle between that of our Parallel Boundary Rig and that of our Pseudo SASS rig (110 degrees) might be good to try because the parallel rig exaggerated the sides a tad too much in some people's opinion. (I happened to prefer the additional contrast). I was looking at your site and thought you might have had something similar in mind with this rig. Of course, the parallel rig has front-facing caps and the Pseudo SASS has flush-mounted caps. For those who want more center, I'm inclined to suggest front-facing caps on two boundaries tilted in on the leading edge a bit, maybe 10-15 degrees. Any thoughts about this suggestion? Rob D.

Studio Stereo Localization Test- 3 Boundary & 1 X-Y Rig

4:03 QuickTime movie [10mb]
October 10, 2006
Mics: Primo EM158's & Rode NT-4





Four mic rigs were set-up in front of a 180 degree arc of five speakers as follows:

(1) Small Parallel Boundary with 6" spacing and foward-facing EM158 mic capsules similar in principle to this rig of Curt Olson.

(2) Pseudo SASS with two boundaries angled 110 dgrees, flush-mounted EM158 capsules at 6" spacing similar in principle to this rig designed by Curt Olson.

(3) Double-boundary PZM fixture with 12" spacing of downward-firing EM158 capsules with 1/20" gap based on suggestion in Crown PZM Applications Guide pdf

(4) Rode NT-4 Single Point Cardiod X-Y array mic with -10dB attenuation pad defeated in the cable.

NH700 Manual Record Level: Hi Sens "15." No changes in the recordings were made. Rob D