Yeah, me too..Hopefully that won't be a year from now.. //content.invisioncic.com/y282845/emoticons/uhoh.gif.c07307dd22ee7e63e22fc8e9c614d1fd.gif
Found this while searching the web about Cyclones:
The only rotary driver currently available (not any more!) for DIY is the "Cyclone", another Danley design, produced by Phoenix Gold. The Cyclone is quite different from the ContraBass, looking like a ducted fan.
The Cyclone is based on a revolutionary new technology that uses the rotational force of an unconventional moving_magnet system to drive a radiator directly. This new system converts low frequency signals into acoustical output without the physical limitations of conventional voice coils, cones, spiders, and surrounds. The result of this innovation is a subwoofer with ultra low distortion and 3 times the displacement of a conventional 12_inch subwoofer.
The Cyclone looks like a modified ducted fan _ a 12" outer cylindrical housing with what appear to be two simple fan blades attached to a central shaft, but with the addition of a pair of vanes. The motor uses a moving neodymium magnet within the rotor, with the VC anchored to the stator. This gives it excellent power handling (300 W, continuous).
Like any other driver (even the Contra's), the Cyclone also produces a back wave and so the same enclosure decisions have to made when designing with it as with a more conventional driver. This is a little difficult because normal Thiele_Small parameters are largely meaningless for a driver of this type. (It is worth noting that Fs is quoted _ at 11 Hz!) As guidance, Phoenix Gold recommends its use in a 3 cu.ft. sealed or 3.5 cu.ft ported enclosure. Due to the extreme excursions possible with this design (125 cubic inches/2 liters displaced), to use it in a passive radiator (PR) design, you'll probably need two 15" PR's.
However, according to Danley, the real key to using this driver well (he has them installed in his own listening room) is to provide sufficient air volume. Continuing the comparison of a Cyclone to a fan, one thing every engineer knows about fans vs. pumps (conventional drivers act as pumps) is that fans can move more air, but they can't generate much pressure. The vanes in the Cyclone prevent it from working exactly like a fan, but neither does it work exactly like a pump either. Still, like a fan, it works most efficiently when working into large volumes. Therefore, to effectively use a Cyclone, you don't want it working into a small contained volume. It would, however, make an excellent driver for a dipole woofer.
"It appears that the product is discontinued. I wonder why. They couldn't tell me. I tought it was rather fun to buy one and test it, but alas... You might find it interesting that our own Tom Danley designed the Cyclone and ServoDrive liscenced it to Phoenix Gold. Unfortunately Phoenix took too many design liberites before final production and all the quality aluminum parts in all prototypes became cheaply molded plastics with poor tolerances and rigidity. Also, the original design was for an IB use, and they then tried to change it to work in many applicaitons and ended up with something which wasn't quite optimal for any alignments at all. For what it's worth,
Tom had a similar pair of these units loaded into a crawl space which had response down to 11_13Hz (I forget). The final Cyclone ended up having some reliabliity problems along with odd parameters for the car market, and ultimately died. Interestingly, I believe one of the Hi_Fi rags had noted a Cyclone in a sealed box to be what he thought was a reference subwoofer and one of the top innovations on the market... and this was a while after the product was out.
