[Vintage-Audio] Using Slate For Sound Dispersion

[Duane Fischer, W8DBF]

Hello All,

I have one James B. Lansing model 4320 Studio Monitor. What a big, 
beautiful, beast! It uses a slate lense as part of its sound dispersion 
structure. The vertical angle is 45 degrees and the horizontal angle is 120 
degrees. Can someone please explain to me how this heavy slate lens 
functions in the J.B.L. sound dispersion design?

If it is of value: The 95 pound cabinet has a 15 inch front firing woofer 
with a crossover to a horn at 800 Hz. There are two front ports for the 
woofer, one on either side of it.

Thank you!

Duane Fischer, W8DBF/WPE8CXO
dfischer at usol.com

HHI: Halligan's Hallicrafters International
http://www.w9wze.net

HHRP: Historic Halligan Radio Project
hhrp.w9wze.net