# New to BFD, and to HT Shack!



## Guest (Oct 27, 2008)

Greetings all!

So im in the process of completing a second pair of custom infinity 12.1 perfect's, and now that i have a BFD, i was thinking about converting my first pair to a sealed enclosure and applying some EQ via the BFD. 

I was playing around with bassbox pro, and found that if i applied a 3bd/octave boost at 50Hz, my output graph is basically flat right down to 15hz! I was wondering if it is possible to set this kind of raise with the BFD, and how i would go about setting it.

I understand how to use the BFD, but im not familiar with how to set an EQ in terms of db\octave (at) freq. 

I know this wont give me in reality a "flat response" due to room anomalies and whatnot, but i dont want to set up my subs for a flat response in this house (renting for the time being, soon to move). 

If you could please help me out, this would be fabulous! Thanks alot!


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## brucek (Apr 11, 2006)

> I was wondering if it is possible to set this kind of raise with the BFD, and how i would go about setting it.


A BFD does not offer shelf filters. 

It is possible to design a shelf filter out of multiple filters in a BFD, but it's not really the best way to go. 

If you want shelving capability, look for an equalizer that has specific shelf filters.

brucek


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## Wayne A. Pflughaupt (Apr 13, 2006)

First, welcome to the Shack!

Are you saying that you have a 3 dB hole at around 50 Hz, and if you boost it up you'll have flat response down to 15 Hz? Or are you needing a shelving filter as brucek noted that will boost everything from 50 Hz down?

The BFD can do the former with no problem, but we can't recommend anything for you since you didn't post a response graph. How much to boost the filter, and at what frequency - it looks like you have a handle on that. The only remaining variable would be the bandwidth - i.e., how wide or narrow the filter would need to be to "fill the hole," as it were. 

If you can't post a graph, or don't want to you can find a formula for calculating parametric EQ filters on pp. 9-11 of this subwoofer manual.

Regards,
Wayne


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