Not clear at all - what is the purpose of the voice coil attached to both spiders and not to a cone (membrane)?
That only low frequencies move the membrane,, not all the range, and the inertia works to move further away the cone
Not clear again - low frequencies from other driver (woofer) will move the passive membrane, but what is the purpose of the voice coil attached to both spiders and not to a cone (membrane)? Voice coil have not any purpose at all, because it is not attached to the cone/membrane.
The small and speedy vibration of a hi pitched sound will not exite the cone, only los speed and biger movements will transfer the energy to the membrane and then the mass of the cone will work like a passive radiator.
The basic idea seems similar to the one used by Thiel in some of their co-axial units:
https://www.stereophile.com/content/thiel-cs23-loudspeaker-page-2"The CS2.3 is the first speaker to use Thiel's new compound driver, for which a patent application has been filed. In this new design, the 1" tweeter and 4" midrange are mounted coaxially and driven by a single voice-coil, which responds to frequencies from about 100Hz up.
Both the tweeter and midrange use anodized aluminum diaphragms, separated by a compliant, cast polypropylene ring—sort of like the surround you find on any cone driver. Above about 3kHz, the tweeter is driven and functions just as you'd expect. Below 3kHz, it still moves but doesn't really push enough air to be a factor. The movement of the midrange, on the other hand, is controlled by the compliance of the polypropylene ring. Above 3kHz, the tweeter vibrates away, but its movements are absorbed by the compliant ring and are not transferred to the midrange cone. Below 3kHz, however, the compliant ring is effectively rigid, and transfers the voice-coil's movements directly to the midrange cone. It's simple and elegant—one of those things that seems so obvious once you see it."
https://www.stereophile.com/content/thiel-cs23-loudspeaker-page-2"The CS2.3 is the first speaker to use Thiel's new compound driver, for which a patent application has been filed. In this new design, the 1" tweeter and 4" midrange are mounted coaxially and driven by a single voice-coil, which responds to frequencies from about 100Hz up.
Both the tweeter and midrange use anodized aluminum diaphragms, separated by a compliant, cast polypropylene ring—sort of like the surround you find on any cone driver. Above about 3kHz, the tweeter is driven and functions just as you'd expect. Below 3kHz, it still moves but doesn't really push enough air to be a factor. The movement of the midrange, on the other hand, is controlled by the compliance of the polypropylene ring. Above 3kHz, the tweeter vibrates away, but its movements are absorbed by the compliant ring and are not transferred to the midrange cone. Below 3kHz, however, the compliant ring is effectively rigid, and transfers the voice-coil's movements directly to the midrange cone. It's simple and elegant—one of those things that seems so obvious once you see it."
Thanks a lot for the reference and your time. In this case I am going for the low end.
I was mislead (an possibly the OP himself) by the wrong title. The title of OP says: passive radiator, also he mentioned "passive radiator" again:
Yes, I know the how the Thiel driver works (and it was similar to a much older design) - it is completely different from passive radiator (membrane) working in a "vented" enclosure.
I think some language differences and creative descriptions are contributing to the misunderstanding.
My reason for bringing up the Thiels was to lend a little credence to the basic idea and hopefully try to get the discussion focused more on the action of the driver instead of the semantics of the title. I wasn't trying to one-up anyone.
My reason for bringing up the Thiels was to lend a little credence to the basic idea and hopefully try to get the discussion focused more on the action of the driver instead of the semantics of the title. I wasn't trying to one-up anyone.
OK, thanks for clearing up!
If we accept the OP design as a variant of the Thiel design, than it might be good as midbass driver with extended midrange, because the OP insists on "going for the low end". But it negates the very purpose of a wide-band driver with partially decoupled membranes (as Thiel's). For woofer duty this is not a good design.
If we accept the OP design as a variant of the Thiel design, than it might be good as midbass driver with extended midrange, because the OP insists on "going for the low end". But it negates the very purpose of a wide-band driver with partially decoupled membranes (as Thiel's). For woofer duty this is not a good design.
Esto de no hablar inglés me imposibilita a comunicarme bien!!!
This is for a Open Baffle design
In a certain point (45 Hz or lower) the coil moves one way and the membrane (cone and the big dust cap) MOVES in the OPPOSITE DIRECTION call it a "resonator" not a "passive radiator"
It seems wrong but they sound good!!
Paul McGowan tell me once in a E-mail
| CEO
1-800-PSAUDIO
psaudio.com Boulder, Colorado
"They seemed to work alright. Nicely damped but not a direction we would be interested in since all our woofers are servo controlled."
This is for a Open Baffle design
In a certain point (45 Hz or lower) the coil moves one way and the membrane (cone and the big dust cap) MOVES in the OPPOSITE DIRECTION call it a "resonator" not a "passive radiator"
It seems wrong but they sound good!!
Paul McGowan tell me once in a E-mail
| CEO
1-800-PSAUDIO
psaudio.com Boulder, Colorado
"They seemed to work alright. Nicely damped but not a direction we would be interested in since all our woofers are servo controlled."
A metà degli anni '90 Cerwin Vega introdusse una serie di woofer, divenuta mitica, chiamata "Stroker".
Aveva un centratore aggiuntivo posto sul centro del magnete con un'asta stabilizzatrice invece del cupola parapolvere.
Then how do you know how to tune your idea and what it's really doing? With no measurements, you'd have to have a lot of faith in your modeling.