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Why so few speakers with Passive Radiators?

Folks,

What are your thoughts on Passive Radiators in speaker design?

I've had many different speakers (and like many here, have heard countless varieties outside my home), from ported, to sealed, to passive radiator, to transmission line.

In my experience by far the best bass has come from the Thiels I've owned - CS6, 3.7, 2.7 which use passive radiators.  The bass in these designs are punchy yet as tonally controlled, or more, than any other speaker design I've heard.  So I figure the choice of a passive radiator must be involved somehow, and it makes me wonder why more speaker designers don't use this method.  It seems to give some of both worlds: extended bass, no port noise, tonally correct.

And yet, it seems a relatively rare design choice for speaker manufacturers.

Thoughts?
prof
rodman99999
6,125 posts
 
Legend- With a little research, you’ll find that both a properly designed/implemented radiator, and the mass of air in a vent, act as resonators and reinforce the system's TUNED bass response.  Below the tuning point, yes- cancellation occurs(and is irrelevant).  That understanding should remove the why and how. Third subject, here: http://audiojudgement.com/bass-reflex-speaker-design/ Then: http://www.accuton.com/en/technology/passive-radiator/
unsound
7,329 posts
 

It seems to me that if one had a cabinet big enough for the size of many of the passive radiators used, why not just add a cross-over and add another woofer? Or just use a larger woofer to start with? Sure there would be some added expense, but I'd much rather have a proper sealed box than any ported design, passive radiator or not.

With DSP and digital EQ having made such strides recently, I wonder why someone has resurrected the eq'd sealed box designs  like the earlier Thiel's up to the 3.5's with active eq bass boosting compensating for the natural roll off? With updated DSP and EQ one could adjust the bass so that not only in anechoic chambers but one's actual room, the most troubling frequency range, the bass, could be optimized.

 True transmission lines are ginormous.
 

nitewulf
422 posts
 
You wouldn't use them unless you need to use them, typically in smaller speakers to increase bass response. If you are designing largish floorstanders with large multiple woofers...why'd you need to use em?
unsound
7,329 posts
 
^What specifically are you referring to?
nitewulf
422 posts
 
Plenty of modern stuff:

Legacy Audio Signature SE and higher level Legacy speakers
Endeavor Audio E-3 MK2
Magico various speakers
Focal Sopra 2, 3

These are all ported or sealed twin woofer designs that go very deep, there is no need for passive radiators.
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