# BFD'ing subs with built in PEQs ?



## Guest (Apr 20, 2007)

I have dual PB12+2/s that I'm about to use a new BFD on. I say about to because when I plugged it in to my subs - I got a hum which I was prepared for due to the excellent reading material here on this site. (gotta go buy a cheater plug)

My subs are stacked on top of each other. 

So I spent last evening examining the filtering aspects of REW in preparation. NEAT! REW suggests 6 filters for my response curve. The most egregarious aspect of my response curve is a very wide peak from 14-20Hz of about 8db.

I was able to use the onboard PEQs on my subs to flatten out that particular peak very nicely.

My question is - is there any preference for using the BFD for all filters? If not, is there any preferred order to adjust them? For example, I could first flatten out the curve with the BFD and use the onboard PEQs to handle any leftover peaks, or I could first flatten a couple of peaks with the onboard PEQs and use the BFD to tame the rest. I'm guessing the answer is "doesn't matter", but can't hurt to ask.

Thanks.


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

Schwingding said:


> I got a hum which I was prepared for due to the excellent reading material here on this site. (gotta go buy a cheater plug)


Umm, no. You should figure out what’s causing the ground loop and fix it. First place to check: your cable TV or satellite antenna feed.




> My question is - is there any preference for using the BFD for all filters? If not, is there any preferred order to adjust them? For example, I could first flatten out the curve with the BFD and use the onboard PEQs to handle any leftover peaks, or I could first flatten a couple of peaks with the onboard PEQs and use the BFD to tame the rest. I'm guessing the answer is "doesn't matter", but can't hurt to ask.


If you have the BFD, there’s no good reason to use the sub’s on-board PEQ. Not to mention, it’s much more difficult to use, since it’s hard to precisely determine the frequency, bandwidth and gain factors.

Regards,
Wayne.


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## Guest (Apr 20, 2007)

Oh I know whats causing it. It is because the location of the subs has required me to (temporarily) power them from one of my non-dedicated circuits for my HT. I have 3 dedicated 20 amp circuits run to my basement for my gear, but the best location for the subs, sound wise, has them in a corner where I didn't place juice from any of those circuits. The solution is to run a line over there, but there's a timeline involved.

BTW, the PEQs on those subs - I don't find them at all hard to use. I have a trick. I use the TrueRTA real time analyzer to find the exact frequency and Q factors. I can watch the screen change as I adjust the peq controls, no guesswork needed.

Thanks for your response!


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

Schwingding said:


> BTW, the PEQs on those subs - I don't find them at all hard to use. I have a trick. I use the TrueRTA real time analyzer to find the exact frequency and Q factors. I can watch the screen change as I adjust the peq controls, no guesswork needed.


That’s not a trick – that’s cheating! :laugh: 

Seriously though, an RTA is indeed the best and quickest way to set a parametric, especially an analog one. I typically assume people _don’t_ have one unless they say so! Especially when they cost money, and REW is free! :bigsmile: 

Regards,
Wayne


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