[Jtoivonen]

Just curious.. What are those modifications that are made to it? Does anyone know?  Is it  Eminence Beta 12??

[baka]

Just curious.. What are those modifications that are made to it? Does anyone know?  Is it  Eminence Beta 12??

Ask R. Bastani.

[gary]

There's quite a bit of info at the Bastanis board on audioasylum. Basically if I remember correctly he treats them with varnish over a long period of time to get exactly the mechanical properties he wants across the basket, from the center out. Hard to believe it works, but it does if hearing is any indicator.

Gary

[scorpion]

Data says that the Bastani 12" is more close to Beta 12 CX, but it is probably a true OEM unit. There are some disclosures about cone treatment in the Bastani Forum. Not totally secrect but not everything reveald as you would expect.

/Erling

[Telstar]

Why don't you buy the drivers from Bastanis?
They are not that expensive.

[Jtoivonen]

Why don't you buy the drivers from Bastanis?
They are not that expensive.

Well, because I was just curious.. And I have a pair of used Beta 12 drivers which cost me about 40€. So it would'n be a disaster if I made a mess out of them
 

[openback]

Here is a project of Bastanis clone:

http://www.diyaudio.com/forums/multi-way/142186-my-first-open-baffle-speaker.html

[driguy]

I have the Bastanis speakers (both Prometheus and Apollos) and worked with him at a RMAF in the past. The drivers are custom built to his specs and then specially treated by him. A cursory look at the specs of any 12" Eminence driver will convince you that none are designed to extend out to 9,500 Hz. That is where the crossover is set on his kits. One of the reasons that they sound so good IMO is the very simple crossover (that helps minimize phase problems) and the crossover point which unlike the vast majority of speakers is high enough to avoid muddling up the critical range of 2500 to 4500Hz. I think they sound a lot like single drivers but with much more extension on top and bottom end.

[baka]

Just curious.. What are those modifications that are made to it? Does anyone know?  Is it  Eminence Beta 12??

http://www.6moons.com/audioreviews/bastanis/prometheus.html

"  Robert Bastanis, the designer of the Prometheus Mk. II and a complete line of speakers based on the fullrange/open-baffle philosophy, has analyzed this state of affairs and come up with a practical solution that in the Prometheus mirrors the Zu Definition our publisher has embraced with a vengeance. Robert uses a wideband driver manufactured by Eminence Speaker LLC to his specifications, with a voice coil designed more as a midrange driver rather than for the large excursion of a woofer. He then treats the cone to allow it to operate at higher frequencies. This treatment process is truly an artisan creation of Mr. Bastanis and at the heart of his speaker line. In a proprietary four-stage process, Mr. Bastanis applies his own mixture of oil and violin lacquer to the cone (anyone remember proponents of C37 lacquer application to Lowther drivers?). This makes the cone able to flex more in the upper frequency range by loosening the fibers and increasing their elasticity. He simultaneously stiffens the cone by baking it. Lastly, a ring of circular felt pads (floor protectors for chair legs?) is placed around the perimeter of the dust cap to dampen high frequencies reflecting off it. The treated Bastanis wideband driver is then able to be operated between approximately 100Hz and 12kHz, covering the critical frequency range of most music with a single driver. After these treatments, the driver needs about 400 hours of break-in so kit builders should be prepared. "