[Otto]

Thanks for the discussion guys; it's the kind of thing I'm looking for.

About the shelf filter: I think it's lame that it's not well defined in the Behringer manual. When I read it, I didn't question the definition of "shelf filter". It's not somthing that I've really run across before, but the 12 dB per octave implied to me that the slope continued infinitely in whatever direction. So, Wayne, you're saying that the shelf filter has a slope that starts as some frequency f, and is applied for over some frequency range ([/i]r[/i]), at which point the remainder of the frequency spectrum (ideally, until infinity) remains simply cut by some amount, G. How big is r? An octave? Something else? If r is one octave, then the absolute value of G will always be either 6 or 12 dB.

I guess it doesn't really matter too much, but I'm disappointed to hear that it doesn't work the way I thought it would.

I think I will consider a "real" crossover. Any suggestions for one that works down to, say, 10 Hz? With a cost of < $300? And a variable phase control? I'll check out the Rane later today.

As to making LPFs with the BFD, I agree with brucek that it's possible. I've played with it to some degree of success. I'll continue to poke around at real crossovers and such. Perhaps I'll go back this weekend and see if I can do better than what I have. FWIW, my sub will play >> 300Hz, so I'm up in the 2 kHz range when I'm quashing that sub output. Still, it seems to work OK. I guess I just wanted a definitive LPF on that thing.

Thanks!!!!