# My First BFD Filters - Suggestions?



## Dan Twomey (Nov 10, 2007)

Recent events.

I built a DIY sealed sub as can be seen here,
http://www.hometheatershack.com/forums/sealed-subwoofer-build-projects/62061-my-epic-12-2cu-ft-build.html

Not long after that I smoked my old sub amp so I bought an iNuke NU3000. Right after that I picked up a DSP1124P.

Now I do have an ECM8000 and MobilePre on order but until then I decided to jump into a little manual tuning using my old RS SPL meter.

Here's my first try using a pink noise file to set my meter at 70db prior to all measurements. Below is a is my Excel info with the Pink line being the BFD line and the navy line being the BFD in bypass mode. I have five current filters that I have manually entered.

Freq. Bandwidth Gain
20 60 +10
28.3 15 +10
35.8 1 -10
63 30 -20
80 15 +16

Here's the chart and values

















How'd I do? Any suggestions?

Regards,
Dan :nerd:


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

Wow, does it really put out down to 10 Hz??

The blue baseline looks a lot different from the graphs posted on your build thread, specifically the big hole at 28 Hz.

The -15 dB cut at 63 Hz, what’s that about?

Regards, 
Wayne


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## Dan Twomey (Nov 10, 2007)

10hz. Does the sub driver oscillate. Yes. My efforts to tame a slight peak at 63 may have only caused a valley at 56.

Regards,
Dan


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## Dan Twomey (Nov 10, 2007)

More experimenting but back to basics. Here's the manual measurements of my two fronts with no sub. Volume set with pink noise at 70db. For the next step I'm going to set my processors sub crossover at 60Hz and just use my sub amps volume control to see what base results I can get.










Regards,
Dan


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## Dan Twomey (Nov 10, 2007)

This is a simple crossover at 60Hz with no filters and sub amp at 75% power.

Well this attempt didn't work out that well. It seems easy to raise or lower the output below 28Hz just by applying more power but the area between 30-60Hz is too hot. I'm going to change crossover to 30Hz to see what happens.










Regards,
Dan onder:


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## Dan Twomey (Nov 10, 2007)

Well that didn't work! onder: Next step a 45Hz crossover with no filters.










Regards,
Dan


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## Dan Twomey (Nov 10, 2007)

Hmmmmmmmmm.........onder: I think I'll go back to 30Hz and use two filters to boost the 28Hz and 50Hz areas.


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## Dan Twomey (Nov 10, 2007)

More fun with two filetrs added to a 30Hz crossover. Filter #1 is 25Hz, Bandwidth +10, Gain +10. Filter #2 is 57Hz, bandwidth 30, gain +10. Her's the results.


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## Dan Twomey (Nov 10, 2007)

Ha! Even with very basic tools I may be getting there. This one has three filters. 28.3Hz bandwidth 10 and gain +15, 35.8Hz bandwidth 10 and gain -15, and finally 57Hz bandwidth 30 and gain +10.

Here's the chart.


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

That's some really severe filtering, so I hope you have miles of headroom. Anyway you can move the sub to a location that would display less-severe depressions that would make for easier equalization?

Regards,
Wayne


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## Dan Twomey (Nov 10, 2007)

The sub is going to be moved to a different, not necessarily better, location when I get my REW combo setup. This is just me getting familiar with tinkering with filters. BTW I've already read your house curve article http://www.hometheatershack.com/forums/rew-forum/6818-minimal-eq-target-levels-hard-knee-house-curve-long.html and I'm quite intrigued. Expect to see quite a few posts by me in a month or so.

Regards,
Dan


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