I had come to know about Passive Radiadors through JBL in the
60's. I know they have meanwhile fallen out of favour when
compared to the performance of vented boxes - except for very
special applications such as when the duct dimension won't fit
the speaker box. I would be very interested to read JBL's take
on things while they used them. Although I've tried, I can't find
any literature about these on the 'Lansing Heritage' site. Is it
there by chance and I'm simply not finding it?
Thanks for any help