[Wayne A. Pflughaupt]

I stand corrected, guys – thanks.

Otto wrote:

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 (r), 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.

Here’s what a shelving filter looks like:

All I can figure out with Behringer’s 6/12 dB thing is that one (presumably the 12 dB) would maybe make the transistion between where it starts and levels out sharper or more “sudden.”

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.

Not sure what you mean by “works down to.” I probably led you astray recommending a “real” crossover – I forgot that it’ll probably be hard to find one with a crossover frequency lower than 40 Hz, since most pro subs are pretty much done by then, so the BFD might be your best bet after all.

Still, it can’t hurt to look. I have these brands in my “Pro Audio Manufacturers” Favorites: Applied Research & Technology (aka ART), Ashly, Behringer, Carvin, dbx, ElectroVoice, Furman, Peavy Phonic, PreSonus TDM, Yamaha. There is also the “DJ brands” (read low-end) like Nady, DOD, Pyle, Samson

Regards,
Wayne