Passive radiator


Were passive radiators an ultimate failure? Does any speaker company still use them? A friend of mine is asking about them in regard to vintage speakers, and all I remember is being unimpressed. But I don't want to tell him that without some back-up.
arnettpartners
In the late 70's, at Tech Hifi, among all the major speaker brands and models sold that I heard, my overall favorite for a somewhat larger room were the OHM Hs, one of just a few, and the only OHM that used a passive radiator. They were the ones that did everything right. I think they went for $900 a pair or so back in 1978.

I did not have the right room or budget for those back then so I ended up with smaller ported Ls, which sounded similar on a smaller scale.

I came very close to going with new refurbed OHM Hs a couple years back when looking to bring my setup "up to date" based on the continued strong performance of my Ls, but decided to go with other models that can do the imaging and soundstage deal better than most box speakers from teh 70's.
Hey, thanks guys. He is particularly interested in the Reynolds Advance A-2 and Genesis Physics 3's both I believe from the 70's. Anybody know these speakers?
It's a speaker with all the components removed including the
magnet. It is used to replace a port.
The correct way to design a passive radiator, is to run the
Thiele/Small parameters of the woofer and cabinet internal
volume, for a ported/bass reflex(ie:Fourth Order) alignment,
using the diameter of the radiator as, "port diameter." .
Then adjust the weight/mass of the passive radiator's cone, to
match the mass of the air that would have occupied the
resultant port's volume. A passive radiator should always be
1.5 to 2 times the diameter of the woofer.