Thiel 3.7

Hmm...I *do* listen to a lot of mono recordings, maybe I can get by with just one...

Has anybody else noticed that some photos of this speaker show what looks like a second passive radiator in place of the conical-diaphragmed bass driver with comparitively mild corrugations that we first saw? With no obvious attachment point for a voice-coil on the heavily corrugated but seemingly essentially flat, dustcap-less diaphragm, might these just have been stand-in appearances by the passive for photo ops while the real driver was out being worked on? Or could the final bass driver in fact employ, similar to the midrange ring, a non-conical, non-dome, corrugated flat diaphragm, outwardly identical to the passive? That would be radical, although I prefer the differentiated look with the grille removed.

Thiel has now posted a new pdf detailing the 3.7's.

Some interesting stuff there. As I speculated about in my previous post, the actual woofer does indeed sport a corrugated flat diaphragm, outwardly the same as the passive and different from earlier photos. The blurb talks about elimination of cavity resonances with this shape, probably more of an issue for a woofer in a first-order design. (I notice that Thiel has now adopted the term "wave-shaped" to describe the woofer and midrange diaphragms. Guess that's more poetic than "corrugated".)

Also learned that the curved cabinet isn't made from scored and bent MDF, but 15-layer molded hardwood ply, a first for Thiel I believe and more unusual. And the baffle is aluminum, like the dome-shaped top. No details yet on the interior construction, but the back seems angled-back similar to the front, although not the same angle. They're specifying 90dB anechoic sensitivity, but a 2.8 ohm minimum impedance, so beefy solid-state would still seem to be the preferred amplification. Anybody hear this at CES?

$10K, 33Hz +/-2 dB from an out of time and phase drone cone, 2.8 Ohm minimum impedance, metal back. Of course the proof will be in the listening, but, despite the engineering novelties and the excercise in cabinet craft, I can't help but think they're aiming at the wrong targets.

Here's a little vid on the 3.7. Harley doesn't know the difference between phase coherency and time coherency, but Jim Thiel does ;)

http://www.avguide.com/features/ces07/videos/thiel.php