Can a high pass subsonic filter be setup in a BFD?

[deromax]

If not, anyone ever measured the low-end response of the BFD? It's advertised as 20Hz-20kHz at -3 dB, does it roll off significantly below 20 Hz?

Thanks!

[Jerm357]

Here you go.

[Owen Bartley]

Wow, that's pretty impressive actually! Thanks for putting that into perspective Jerm.

deromax, you can't really do a proper subsonic filter with the 1124, because it doesn't support shelf filters. I can't remember if the 2496 does or not, and a quick Google didn't help much. What you CAN do is construct a pseudo shelf with a couple of very sharp cuts below the frequency you'd like to cut off at, maybe even one that isn't so sharp to start the roll off a little below the cuttof frequency. It's a bit of a hack job, but it should help to protect your driver a bit.

[brucek]

What you CAN do is construct a pseudo shelf with a couple of very sharp cuts below the frequency you'd like to cut off at

Not really possible, since the lowest programmable filter is 20Hz. To affect below 20Hz, you'd require a bandwidth that would affect an equal amount above 20Hz, which wouldn't be desireable...
The BFD can approximate an LPF, but not an HPF......

brucek

[deromax]

Hello! The 2496 allows a high pass at a minimum of 20 Hz. I'm doing exactly this, with excellent results. But I may decide to reclaim two output channels on the 2496 to bi-amp my upcoming center channel speaker project. So the sub processing would have to migrate to some other processor for P-EQ and subsonic filter. My subs being vented, the subsonic filter is requiered.

Also, thanks Jerm357 for the graphs!

[Jerm357]

Your welcome, but all the measurements were done by Ilkka so all the credit goes to him. I figured these graphs would come in handy some time ago, so I saved it.

[Owen Bartley]

brucek wrote:

Not really possible, since the lowest programmable filter is 20Hz.

Ah, . I figured I'd get something wrong if I went and ran my mouth off on theory alone. Thanks for the correction Bruce, I probably should have dug out my manual, or at least looked it up online. For some reason I thought I remembered putting in some low boost on my sub, but it must have been at or just above 20Hz.