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Discussion in 'Microphones' started by owokasib, Apr 23, 2011.

  1. owokasib

    owokasib Active Member

    I want to connect Feedback destroyer(Behringer DSP1124P) to the 24Channel mixer in order to eliminate feedbacks on all mics (6 in all).I am not using any compressor. The mixer image below is a replica of my own except that mine has 24 channels.


    Each channel on the mixer has MIC IN(XLR), LINE IN(1/4-inch TRS), INSERT IN(1/4-inch TRS). It also have GROUP OUT 1 & 2, AUX SEND 1 & RETURN 1, AUX SEND 2 & RETURN 2 (all 1/4-inch TRS).

    The mics are currently connected to the MIC IN on Channels 1-6.

    Please advise on how best to connect the equipment to achieve my objective. Also required is your opinion on the cabling indicating type of connectors e.g. balanced cables.

    Thank you.
  2. bouldersound

    bouldersound Real guitars are for old people. Well-Known Member

    Feedback is generally much more of a problem on monitor mixes than on the main mix, so you would put the unit in series with the monitor output (probably one of the aux sends) of the board and the power amp. If you already have manual eq on the monitor sends put the feedback destroyer before it. Use balanced cables, TRS-TRS or TRS-XLR, from the mixer to the unit.

    Be sure to set the overall monitor mix level so the DSP1124P gets plenty of level or it won't detect feedback. You should come close to peaking its meter fairly regularly. Use the power amp to trim the volume down to what you need on stage.
  3. Kapt.Krunch

    Kapt.Krunch Well-Known Member

    You may want to be aware that each signal run through the monitors, and then possibly picked up by the nearest mic (and other mics), is going to affect the frequencies that thing has to minimize...and any change to any frequencies being picked up my any mics, and then fed back through the monitors may necessitate further tweaking. In other words, a particular feedback eliminator setting may be useful for one mic/monitor set, but if using a different mic, in a different placement, near a wall or bouncing off something, that first setting might not be ideal for that mic/monitor set. The more mics and monitors you feed through one setting, the more you may end up with each mic and monitor setting cumulatively adding up where there's not much of a signal left at all from any of them.

    If the first monitor is feeding back at, say, 4kHz through its mic (or another), then you'll attack that. If the second monitor is feeding back at, say 2.8kHz, then you'll attack that. So now, you've got 4kHz and 2.8kHz attenuated. If the drummer's mic and monitor is bouncing off the wall and feeding back at some different frequency, then you'll attack that.

    You'll keep doing that, and raising the output level, which may introduce more problem frequencies. Basically, you may be forever chasing your tail...especially the more mics and monitors you deal with, trying to use one setting for every channel.

    Not to mention you're taking a chance using a product of suspect reliability and quality at a paying gig. What you may end up with is a Behringer sound destroyer, if you're lucky and don't end up with a Behringer miniature smoke machine.

    Of course, all the problems of one EQ for many mics/monitors is true with, or without, that box. Mic choice, careful mic/monitor placement, judicious EQ, and a reasonable stage volume will likely help more than a 'magic box', don'tcha think?

  4. Davedog

    Davedog Distinguished Member

    One of the most gawd-awful sounding devices ever built. They cause more problems than they solve and your monitors will suck by the end of the night. Invest in quality 31 band EQs with a limiter built in. And learn to use it. Also learn about mic placement and selection.
    audiokid likes this.
  5. bouldersound

    bouldersound Real guitars are for old people. Well-Known Member

    99.5% operator error and misplaced expectations. They are no substitute for the basics, but people seem to think they will automatically solve problems caused by crappy monitors, cheap mics, shared mixes and out of control stage volume. They won't, but with an informed operator they can be an effective tool.

    Another excellent tool which is so often misused with terrible sonic results. The problem is ignorance not the tool.

    How much time have you devoted to trying out a Feedback Destroyer, if for no other reason than to have some solid evidence pointing to the product rather than the operator as the cause of the bad sound you experienced? I have spent many hours discovering what they can and can't do. They can reduce feedback with less impact on the sound than a 1/3 octave eq. They can't perform miracles.

    Goes without saying, but it doesn't hurt to mention it again once in a while.

    I know I won't win any friends disagreeing with the big dogs, but I can't stand by as this kind of misinformation is spread without a shred of evidence to back it up.
  6. bouldersound

    bouldersound Real guitars are for old people. Well-Known Member

    Merely anecdotal, but my two have been bouncing around in the back of the van for years, suffering temperatures from -20°F to +120°F and they still work. Probably there was some mistake at the factory where they forgot to start the self destruct timers.

    That's a false dichotomy. It's the expectation, reinforced by your words, that Feedback Destroyers are meant to be used in place of getting the basics right that leads to the problems. When used in addition to good stage setup they can be very effective.
  7. Davedog

    Davedog Distinguished Member

    I owned one for four years and I have a lot of experience mic'ng stages and studios. I agree that with someone who knows what they are doing any tool can be a Godsend but these are not simply plug and play and after all those years of dinking with it in lots and lots of venues and with quality monitors and mics this is my opinion. Theres no misinformation offered. As you yourself said, "they are no substitue for the basics" and the reality of these type of devices ESPECIALLY the Be*7^53ger isthey are NOT plug and play as the literature would have many believe. I knew going into it that it would require some usage and a learning curve and for my use, I was simply looking for something to help at the time. I have owned several PA's some of which were used in a rental capacity and had decent quality components in all of them.
    Your points are well taken but the "shred of evidence" quote doesnt fly here. I make no claims on ANY post without knowledge to back it up.

    The OP is a beginner as you can tell from the post and the gear he's attempting to use will not help as easily as he would like to believe.

    Turning down the stage to a usable volume will always be the best start to a better monitor mix. Better gear will always trump wanna-be gear and use and knowledge gained from such information and education will always be a boon to a persons abilities.

    However, that particular piece of gear sucks the life out of the tone in the monitors and as Kapt Krunch said, its abilities to assess multiple mics on a busy stage is minimal at best.

    So, yeah, I'm not talking out my ass about something I spent a lot of hours with in a lot of different venues. You can like em all you want and kudos to you for getting the most out of a marginal product. But thats just my opinion and not some hearsay fomented on a web-site dedicated to sound.
  8. bouldersound

    bouldersound Real guitars are for old people. Well-Known Member

    Okay, you know what you're talking about. But I've heard much the same thing from people who had one bad experience, saw the unit in the rack and directed all the blame on it. If you had prefaced it with something like "Given your probably limited skill level..." I would have agreed completely. If nobody else had posted the warning I would have myself, after answering the OP's actual question.

    The marketing does imply it will work miracles, but on balance the manual gives a basic lesson on how feedback is caused and says in bold type

    Chapter 8 is titled "Problems do have a cause" and lists some of the basics that should be addressed.

    owokasib, if you are having trouble with feedback step #1 is to lower the volume. If that isn't possible or doesn't solve the problem reposition microphones and/or wedges. Then apply conservative amount of manually controlled eq (which can be done with the DSP1124P or a more conventional eq). Automatic feedback suppression should be far down the list of techniques to use. The manual tells you as much and it also answers your original question.
  9. Davedog

    Davedog Distinguished Member

    My intent was as it was. To squelch any thoughts the OP has that this unit will magically solve his feedback problems.

    I will determine my statements and preface each with what I intend to say.
    You have the ability and the desire to continue instructing anyone with your acquired knowledge and to do so in any way you wish. But dont tell me what I need to do on this website.

    I think I already know.......the almost 4,000 posts should about cover that.

    BTW, since we are comparing expertises here, how long did it take you to "learn" what one of these units would or would not do? And, was using one of these your very first experience in live sound control? Did you know how to hook it up when you attained one?

    You see my point.
  10. bouldersound

    bouldersound Real guitars are for old people. Well-Known Member

    Right. I was just explaining my overreaction.

    Point being that I was up to coping with a new piece of gear and the unforseen consequences while the OP probably isn't.

    These kids have no idea how lucky they are to have people like you looking out for them. I just got tossed in with the lions.
  11. owokasib

    owokasib Active Member

    Thanks all.

    I am greatly blessed with your mix of experiences.

    I am sure wiser for it. I am going to pay more attention to the issue of basis raised in all of the posts. I will implement the suggestions and get back to the house with my sumssion in due course.

    Once again, thanks.

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