Ff85k?

[Kensai]

Has anyone used these drivers?

Siming them in WinISD, sealed they look to F3 just above 200Hz in a tiny (~40"^3) box. I'm interested in using them full range inside my large 3way Yamaha cabinets by installing a small box, possibly even smaller like 15"^3 to cause a sharper rolloff, behind one of the cutouts, sealing the other small cutout, and then using the existing Yamaha 8"er crossed down low to mate up with it.

So, I'm wondering if the FF85 is actually a high SQ driver or not. Would I be better served with a different model possibly stepping up to one of the 4"-4.5"ers and crossing lower.

Secondly, as to the crossover . . . I'll be running whatever I come up with full range, but the 8"er (which may eventually be replaced with Dayton SD-215s) will need to be low passed, and I'm only intending to use a simple inductor on it. Should I be crossing it to where its curve and the Fostex's cross at -3dB? That's something I've never exactly gotten the gist of.

Thanks,
Kensai

[Rudolf]

Originally posted by Kensai
Has anyone used these drivers?

Yes.
But I have not heard many other 3" FR drivers for comparison.

... sealed they look to F3 just above 200Hz in a tiny (~40"^3) box. I'm interested in using them full range inside my large 3way Yamaha cabinets by installing a small box, ... , and then using the existing Yamaha 8"er crossed down low to mate up with it.

200 Hz would really be the lower limit. And you better have a 12 dB HP Xover to keep them from excessive excursion, when crossing that low.

So, I'm wondering if the FF85 is actually a high SQ driver or not. Would I be better served with a different model possibly stepping up to one of the 4"-4.5"ers and crossing lower.

I believe the FF85K to belong to the top FR drivers in its class. But if you really want to keep it full range, you better should step up to 4"-4.5" - without crossing lower.

Should I be crossing it to where its curve and the Fostex's cross at -3dB?

I am no expert with cross overs, but AFAIK you cross at -3dB to get a linear SPL transition (on axis) and at -6dB to get a linear power transition (in room).