Behringer Feedback Destroyer

[Chris D]

Following up on a post elsewhere in the forum on a sale, I'm interested in the Behringer Feedback Destroyer. (BFD) Talking to Bob, apparently this can only be used on a subwoofer channel and not other speakers. I'm wondering then what this item can do for you in a home theater setup. Reading through the instruction manual, it seemed to me to only be useful in a setup with a microphone and speakers, such as in a studio.

Those who have this, what do you use it for, and what does it do for you? :?:




CHRIS
Luke: "Hey, I'm not such a bad pilot myself, you know"

[Kevin P]

Talking to Bob, apparently this can only be used on a subwoofer channel and not other speakers.

Well, you could use it on other channels, bearing in mind that you would need 3 of them to get 6 channels and that you'd be introducing another stage of A/D and D/A conversion on those channels. The biggest use for these things in an HT environment is as a subwoofer EQ.

I'm wondering then what this item can do for you in a home theater setup. Reading through the instruction manual, it seemed to me to only be useful in a setup with a microphone and speakers, such as in a studio.

It has lots of features for use in a professional/live/stage environment--its main purpose is to detect feedback and suppress it via an automatic parametric EQ cut, but it can also be used as a flexible digital parametric equalizer with 12 separate filters per channel. In a HT environment, it is commonly used to compensate for room gain ("humps" in frequency response caused by standing waves, reflections or resonance) commonly experienced with subwoofers in a room. For example, I have a huge hump around 45-50 Hz in my room, and smaller humps around 70-80 Hz, which made my sub sound very boomy without equalization. When I added the BFD, and programmed it to reduce the sub's output at these frequencies, I get a much flatter response in my room at my seated position.

You may want to get in touch with our own Sonnie Parker, as he is the resident BFD guru here.

KJP




Official Computer Geek and Techno-Wiz Guru of HTGuide - Visit Tower of Power
My HT Site

[Chris D]

Thanks Kev!

Yeah, I searched, found, and read the BFD Setup Guide that Sonnie wrote. Some good stuff there if/when I do my own.

So as I understand it, the basic concept of the BFD would be to tune a subwoofer to a particular room to create a constant volume sound heard by the listener for each frequency? Hence a "flat" output? That I can understand.

But why is doing this for a subwoofer different than for all other speakers? You'd want a flat response from each channel, methinks, not just the sub. What's different with the bass range?




CHRIS
Luke: "Hey, I'm not such a bad pilot myself, you know"

[sfdoddsy]

There are a few reasons the BFD is generally only used for the bass.

Room modes are usually worst for bass frequencies, so there is perhaps less reason in the mids and treble.

Also, people are concerned about the audibility of the extra A/D D/A stages when used full range.

Personally, I am all for full range EQ, but with something a little more sophisticated than the BFD.

Steve




Steve's DIY Dipoles

[Sonnie Parker]

Chris, if you look at the specs on the BFD they are respectable:

System specifications
Bandwidth 20Hz to 20kHz, -3dB
Noise >-94dB, unweighted, 20Hz to 20†kHz
THD 0.0075 % typ. @ +4dBu, 1kHz, Gain 1

Digital Processing
Converters 20-bit Sigma-Delta, 64/128-times Oversampling
Sampling Rate 46,875kHz

There has been some discussion about using the BFD as an entire system EQ..... I believe I read somewhere (several months ago) that someone has done this with good results. They are much more flexible than the other system EQ's available and the specs are comparable from what I've seen.

For $130 you could try it and see if it works good for you, if not, you shouldn't have too much trouble getting your money back. They are still selling like hotcakes.






SONNIE

[Chris D]

Sonnie, I think I'm going to go for it. I'll get one, planning on using it for subs. Then while I've got it I might try it out on a full range channel just for kicks to see what happens. It shouldn't damage anything, so it might be an interesting experiment. If it happens to work well, then I'll get some more.

Has nobody else that owns BFD's ever tried it out on a full-range channel?




CHRIS
Luke: "Hey, I'm not such a bad pilot myself, you know"

[Eduardo]

Chris, If you are going to try this witha a full range channel, check this out. I plan on buying this when I build my mains.

http://www.behringer.com/02_products/prodindex.cfm?id=DSP8024&lang=eng

The DSP8024 features a 31-band graphic EQ with a real-time analyzer and an Auto-Q function for automatic room measurement and correction plus three bands of parametric equalization. Further highlights include a peak limiter, an adjustable delay of up to 2.5 seconds, a noise gate and BEHRINGER’s renowned Feedback Destroyer.

More info

http://www.ultimatemusicians.com/article.php?sid=32

I found many sites that sell this product ranging from $180-$230

http://home.nc.rr.com/ejimenez

[sfdoddsy]

I've used the Ultracurve 8024 for full range EQ and it does make, I think, an audible improvement. However, there is a problem with the A/D section on low level inputs with quantization noise.

Behringer have just announced this, however:

http://www.behringer.com/02_products/prodindex.cfm?id=DEQ2496&lang=eng

It has ten bands of parametric EQ per channel, a 1/3 octave room EQ system and 24/96 AKM A/D D/A section. They quote a dynamic range of 113dB. Even better, perhaps, it has digital ins and outs at rates up to 24/96.

This should street for under $300 and would be certainly worth trying out.


Steve




Steve's DIY Dipoles