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Cheapest Behringer Feedback Destroyer Pro DSP1124

Discussion in 'Subwoofers' started by AvAl, Feb 23, 2005.

  1. AvAl

    AvAl
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    If anyone is considering buying one of these 'babies' to equalise out their sub, as I've just decided to do, I doubt you'll find it cheaper than £66.75 delivered here from Blue Aran - that's even cheaper than a brand new one just sold on Ebay! I reckon that's a damn good deal :clap:
     
  2. eviljohn2

    eviljohn2
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    I got mine from Blue Aran, excellent service and they were the cheapest I could find.
     
  3. mhuk05

    mhuk05
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    Does it work "out of the box"? Does it do the same as an SPL- what/ how does it work (sorry for sounding stooooopid").
     
  4. eviljohn2

    eviljohn2
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    It's certainly not an "Out of the Box" piece of equipment. Check Nimby's "How to use an SPL meter" sticky at the top of this forum to give you an idea of what's involved.

    There's nothing particularly tricky to do but it's important to understand the basic physics of what you're doing and have plenty of time to spend getting it right. :)
     
  5. Roam

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    Cheers mate! I think I'll bag one next week :smashin:
     
  6. AvAl

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    EvilJohn2,

    I've been looking at my response curve and figuring out how best to flatten out the curve by reading the articles on BFD usage. I seem to have peaks 'binding' with eachother causing a mountain range effect rather than separate, simple peaks. Did you have this, if so, is there a trick to flattening these combined curves, which seem like they'll be more difficult to deal with than individual peaks. Did you have any troughs? If so, did you raise the gain on your sub to lift the overall frequency curve so that you didn't have to use the gain on the BFD, which I believe is recommended (lower the peaks rather than raise the troughs)
     
  7. eviljohn2

    eviljohn2
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    I'm not sure what you mean by having several peaks "binding" at the same frequency, can you clarify this a bit? We need to consider the single measurement position which will certainly include interference from any subwoofers or main speakers that you have. My main speakers and subwoofers interfere constructively quite significantly around 85Hz. We're dealing with the single frequency response curve so the exact details of how each peak/trough is formed isn't really relevant when using equalisation like a BFD. When dealing with a thin "tall" peak within a wider "short" peak you can use 2 different filters, in various combinations to help sort it out. Bear in mind that the effect of the filters will be cumulative so if you put a 1dB cut and a 4dB cut using 2 different filters at the same frequency, the total reduction will be 5dB.

    I havn't got my BFD going properly yet (I have 2 subs but can only connect one until the remainder of my 1/4" plugs arrive so have opted for the all-or-nothing approach and havn't actually performed the EQ yet). I can give you some thoughts though...

    My recommendation is just to ignore troughs. They're usually very narrow and are very difficult to deal with, you're right that applying boosts to them isn't recommended. Rather than aiming for a completely flat response I think it's preferable to keep the extra headroom across the entire operating range. Troughs only really come to note when performing detailed analysis like this and don't really show up in normal listening (apart from the occasional full frequency sweep but we can't have everything without spending thousands on bigger/multiple subs ;) ). One of the biggest "problems" with BFD's is that people have to apply their own knowledge and instinct to get them working properly aside from the few general rules of thumb. :)
     
  8. theo cupier

    theo cupier
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    How much do the various connectors for a BFD cost, on top of the box itself? And where can they be bought from?
     
  9. eviljohn2

    eviljohn2
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    It really depends how you want to do it. As the BFD is a piece of "Pro" equipment it only has 1/4" jacks and balanced XLR jacks. You shouldn't use the XLR jacks unless you have a balanced output/input at the amp and sub ends respectively.

    It simply goes "inline" with your sub connection, so you need an RCA plug from the amplifiers LFE out to a 1/4" plug and then the opposite to go from the BFD to your sub.

    I'm planning on doing a proper modification to my sub cables as they were DIY to start with. The problem being that CPC have been out of stock of these for ages and they're not due in until the start of March:
    http://cpc.farnell.com/jsp/endecaSearch/partDetail.jsp?SKU=CN00389&N=401

    If you're after a completely new set of leads for it, I know Mark Grant can terminate his leads with a 1/4" plug appropriately.

    The other option is just to use an adaptor like this:
    http://cpc.farnell.com/jsp/endecaSearch/partDetail.jsp?SKU=CN02175&N=401
    which will only cost a few pennies, your local guitar/audio shop should have these too. :)
     
  10. AvAl

    AvAl
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    Ah, I see. Interesting info. Thanks. I think you've explained what I need to do. I've got peaks close to and hence affecting one another, so it makes it difficult to see where the peaks are actually....peaking :). I think I may have to have some filters close to eachother on the frequency scale, and at different bandwidths also. I think it may well have to be lots of trial and error but following some basic rules as you say. How many filters have you now used for your one sub?
     
  11. BestGear

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    ...anyone using midi and the software to control/setup the box?

    Should make it much easier...trouble is, no one seems to have done it.

    I will have a go this weekend...

    D
     
  12. bob1

    bob1
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    Whats the midi software and how does it make things easier.
     
  13. eviljohn2

    eviljohn2
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    AvAl,
    I'm not using any filters for just the one sub. I'll do the whole lot when I can connect both, doing one just isn't worth the effort.

    bob1,
    The midi software connects the BFD to your computer (that's what the game port is for ;) ). It basically moves all of the front panel controls to your computer desktop and also provides a rough idea of what the filters will look like. I've not used it but would be tempted if I had the right cable. You can download the software from the Behringer site. :)
     
  14. bob1

    bob1
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    I couldn't find the software on the Behringer site but found some on the snapbug site,looks like it will make setting a bfd up a lot easier.
     
  15. JIT

    JIT
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    Would using RCA-Jack adapters be ok or should i get my cables terminated with 1/4" Jacks?

    I know termination would be better but cost does come into things.
     
  16. AvAl

    AvAl
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    That's what I'll be doing for now...am sure it'll be fine and loss won't be huge, and at least for about £3 I can start 'playing' :)
     
  17. eviljohn2

    eviljohn2
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    Adaptors will be just fine, anyone considering using a BFD wouldn't be able to hear the difference. We're only considering low frequency audio signals anyway so use adaptors and be happy with it, loads of people do.

    I'm just going for hardwired plugs as I'll have to add additional terminations to the cable anyway. :)
     
  18. theo cupier

    theo cupier
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    I'm using both the low and high level connections into my XLS200: low level from the 5.1 processor and high level from the power amp to capture the stereo signals from my separate 2-channel pre-amp.

    What's the best way to use a BFD in this scenario? Can I run both high and low level signals in to it? Would I still need high and low cables coming out of the BFD to the sub?

    Should/could I just get rid of the low level connection from the processor and use the high level signal for everything? Presumably running a high level connection is as simple as:
    high level wires from power amp -> 1/4in jack into BFD -> 1/4in jack from BFD -> phono connection to sub low level connection?
    or do I need to terminate this at my sub's high level (Neutrik) connector, since it started life as a high level signal?
     
  19. Daneel

    Daneel
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  20. bob1

    bob1
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    You can't connect speaker level connections to a bfd.
     
  21. BestGear

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    Chaps...

    Yes, the midi software does make it easier as I now have it working!

    It still takes knowledge of what you are doing, but at least its on your pc now....

    Just make sure you have V2 of the software, else you will need Win98....

    D
     
  22. JIT

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    Better to wait then or buy now?

    Wouldn't think the new on would make much difference to what we're using them for anyway.
     
  23. Daneel

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    I agree, it won't make much difference for sub use, just pointing it out.
     
  24. AvAl

    AvAl
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    Ahh, Daneel, yes, very nice...I think in that case we should tell some of the other distributors of the dsp1124, because some are asking over £110 for it!
     
  25. eviljohn2

    eviljohn2
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    As has been said, you can't use a BFD for high level signals I'm afraid Theo. You'll need to get a dedicated AV amp/processor so you can stick with only a low-level input (the new Arcam preamp looks very nice plus it has balanced outputs).

    I use Win98SE, what cable would I need to implement the BFD midi software? I'm not up on pro gear and home automation I'm afraid.

    As has been said, there is a new feedback destroyer due in a few months but I don't think it adds any particular benefits to the HC crowd aside from being able to use additional filters. Anyone that needs to use more than 12 filters is going about the process in the wrong way IMHO though. :)
     
  26. BestGear

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    ...assuming your PC has a MIDI interface on its sound card 15pin D connector, you can go search a midi cable on ebay for about a tenner delivered....
     
  27. AvAl

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    Well, I got my BFD today, and tonight set it up...I am stunned and amazed at what I've seen in my response curve and heard now I've played my first 'equalised' movie. What a transformation. No boomy bass atall, everything smooth, controlled and rich.
    I've put the before and after curves on for everyone to see (blue line is my sub response, and I forgot to get rid of the pink :) ). I found that after getting used to the first filter setting the rest were a breeze - in total took me about an hour and a half. I used 10 of the 12 filters, and could probably fiddle about, tweeking here and there, but, right now, I just don't see the point because my ears tell me it sounds great, however...I think I might ;)
    One thing that I did have to do, which suprised me was from a setting of +0 gain on the amp, I had to raise it to +10 so that the led's on the BDF were just not hitting the red at normal listening level, and then, to equalise the sub with the speakers I had to turn the sub's volume to virtually maximum. Has anyone else had to turn their gain and sub volume up that far? I don't think it will do any damage to the sub. Any comments?
    It all certainly sounds superb! I 100% recommend a BFD!
     

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  28. eviljohn2

    eviljohn2
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    I don't think you need to turn you gain up so that it's just below clipping level, just make sure it's not above.
     
  29. bob1

    bob1
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    My amps level went up from 0db to +8db and the sub volume a little higher than normal but not that much.
     
  30. AvAl

    AvAl
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    EvilJohn2, yes, that's what I felt I should be aiming for, so large explosions and the such, at normal listening levels now peak at around just about half way up the scale, which I'm happy with.
    Bob1, am wondering if I have to push my sub's gain more as my little REL is 100 Watts and your SVS is a rather more substantial 300W :eek: heehee I guess I'm just worried about damaging the sub
     

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