Here's a Karlson coupler for Beta 8cx

about 1.65 cubic foot bulk - built by Weltersys's Dad circa 1960-63.

tuned probably in the upper 90's. Larger than Karlson's K8. Beta8CX, B52/Celestion compression driver - 1.2mH/10uF lowpass - 4uF/0.35mH/12uF highpass with L-pad

would be good in a sub system - very nice on piano and percussion without any back or front chamber damping.

I'll have to open it up and get a look at the slot vents' dms

It ran well with a Visaton BG20 but I need that multiway treble power for percussion to sound "real".

When a couple of slots are blocked, it sounds very much overdamped.

The lowpass gap area = Sd for the average 8 inch speaker.

Its almost large enough for a 10 so a 1.09X version might be fun.


Rough Drawing

A29bkDR.jpg
 
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