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  1. #1
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    Getting Rid of Feedback

    I want to know what do the professional top notch live sound engineers use to make their sound, sound so clean with no feedback, ring. Do they use a feedback suppressor or feedback eliminator. What's the difference between the two? Also do they use a driver rack? I can't seem to fully eliminate ring and feedback out of my sound, and I'm not sure what I need or am doing wrong. I bought a dbx-31band equalizer, but I'm now realizing that maybe I should have bought a feedback eliminator or a feedback suppressor. I have a bbe 2-way compressor and a bbe crossover with the dbx 31-band eq on top going into my mixer, and a crown 2000 amp. The eq helps but isn't fully eliminating the ring noise and some feedback. I have all my high's on my eq turned down, and I have my gains not too loud and have my input on my dbx mic preamp turned down to a decent not too loud level. The quality of the sound is good. But I'm just not getting the clean sound that I want coming out of my speakers with the mics loud and clean enough to hear fully without feedback or ring. I have two EV Elimator 300watt speakers. How can I get my sound to sound like the pro's you see on television doing live concerts. In other words what would be the typical setup equipment to accomplish this. I'm in the ballpark, but feel like I still haven't hit a home-run yet in my sound, ridding it of feedback and ring noise. What do you recommend?

  2. #2
    Aside from what I mentioned to you previously about "ringing-out" your system before the show, there are a few things that "top-notch" engineers may do. They may eq the room using pink noise and some form of RTA, to help compensate for problem frequencies the room itself has/creates. A few may even use a feedback eliminator of some sort, but most often what I've used/seen used is a simple matter of using a mic and a 31 band graphic eq to ring-out the system. Other than that, the best way to eliminate feedback is to use in-ear monitors.

    I used to have a fair amount of trouble with feedback when I first started doing live sound, but after I started ringing-out the system and got more familiar with frequencies the amount of feedback was greatly reduced. It's rare that I have feedback issues but it does occassionally still happen. More often when I've had feedback issues of late, it's because the artist has done something like walk in front of the mains with his mic.

    One of the riders on my desk at the moment is a famous country artist (no names mentioned). BSS compressors, BSS or Drawmer gates and BSS or KT 1/3 octave eqs on the rider... no feedback eliminator/destroyer. He'll be using in-ears primarily, but the stage monitors will still be there as a backup system in case there's a problem with the in-ears.

    EQing is still your best control in most situations. I haven't met a DBX eq I didn't like yet, although some give more control than others. I'd say you're probably in good shape as far as that goes. When I "eq a room" for most shows, I use a piece of music I'm familiar with and adjust eq until it sounds like I would normally expect that piece of music to sound. That's kind of the poor man's way of doing things, but it is fairly common practice by many engineers. Even if you go the more technical approach and use pink noise/RTA, you should always keep in mind that gear doesn't tell you what sounds good; your ears should be the final decision. You can always check with one of your friends/co-workers you respect as a sound critic as a second opinion too, if you're concerned that what you're hearing is not necessarily the same as what other people are hearing.

    I know I'm touching on several ideas at once here, but there's one more thing I wanted to mention and/or get an opinion on. My biased perception of feedback eliminators is much the same as seeing a soundman's eq set to "smiley face" setup... it's an indicator of inexperience or maybe last resort (when it comes to the feedback eliminators), so I avoid the feedback eliminators like the plague when possible. Maybe some other engineers here can give me their opinion if that's their perception too or if it's just me. My opinion in your scenario is that if a feedback eliminator helps you to get more immediate good results then use it; but continue to practice without it when you can so you eventually get to a point where you won't need it.
    Last edited by fstfwd74; 8th Sep 2007 at 16:57.

  3. #3
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    Aside from what I mentioned to you previously about "ringing-out" your system before the show, there are a few things that "top-notch" engineers may do. They may eq the room using pink noise and some form of RTA, to help compensate for problem frequencies the room itself has/creates. A few may even use a feedback eliminator of some sort, but most often what I've used/seen used is a simple matter of using a mic and a 31 band graphic eq to ring-out the system. Other than that, the best way to eliminate feedback is to use in-ear monitors.

    I used to have a fair amount of trouble with feedback when I first started doing live sound, but after I started ringing-out the system and got more familiar with frequencies the amount of feedback was greatly reduced. It's rare that I have feedback issues but it does occassionally still happen. More often when I've had feedback issues of late, it's because the artist has done something like walk in front of the mains with his mic.

    One of the riders on my desk at the moment is a famous country artist (no names mentioned). BSS compressors, BSS or Drawmer gates and BSS or KT 1/3 octave eqs on the rider... no feedback eliminator/destroyer. He'll be using in-ears primarily, but the stage monitors will still be there as a backup system in case there's a problem with the in-ears.

    EQing is still your best control in most situations. I haven't met a DBX eq I didn't like yet, although some give more control than others. I'd say you're probably in good shape as far as that goes. When I "eq a room" for most shows, I use a piece of music I'm familiar with and adjust eq until it sounds like I would normally expect that piece of music to sound. That's kind of the poor man's way of doing things, but it is fairly common practice by many engineers. Even if you go the more technical approach and use pink noise/RTA, you should always keep in mind that gear doesn't tell you what sounds good; your ears should be the final decision. You can always check with one of your friends/co-workers you respect as a sound critic as a second opinion too, if you're concerned that what you're hearing is not necessarily the same as what other people are hearing.

    I know I'm touching on several ideas at once here, but there's one more thing I wanted to mention and/or get an opinion on. My biased perception of feedback eliminators is much the same as seeing a soundman's eq set to "smiley face" setup... it's an indicator of inexperience or maybe last resort (when it comes to the feedback eliminators), so I avoid the feedback eliminators like the plague when possible. Maybe some other engineers here can give me their opinion if that's their perception too or if it's just me. My opinion in your scenario is that if a feedback eliminator helps you to get more immediate good results then use it; but continue to practice without it when you can so you eventually get to a point where you won't need it.
    Thankyou verymuch. This helps a lot.

  4. #4
    My biased perception of feedback eliminators is much the same as seeing a soundman's eq set to "smiley face" setup... it's an indicator of inexperience or maybe last resort (when it comes to the feedback eliminators), so I avoid the feedback eliminators like the plague when possible.


    he he...

    I work in the feild of audio and from time to time I will do a workshop for a church (the biggest offenders of both smiley-faced EQ curves and feedback eliminators....).. it's amazing that 100% of churches who have not had a sound pro come and look at their system will have a smiley face or Feddback killer...

    I had one little church and the first thing they said was 'we can't hear ourselves in the monitors' so I looked at their gain structures from mic channels to aux sends to the EQ inline between the board and the amp, then I get to the amp, it's an older amp with a 9 band graphic built in, had the biggest smile you've ever seen, the lowest and highest sliders were jacked all the way up, and the middle-most were all the way down..... I set the smile to a grimmace (all at -0-) and tried a few mics out, it was like I had given them twice the volume with more clarity, they were amazed, I was not. I also had to tell them that if they can't see the HF horn in the monitor box then they need to move their music stands (they had three music stands across the front that were completely blocking the HF horns in the monitors....)

    Other places have had such wacky feedback killers and EQ cominations that all it took was hitting the 'bypass' button to make a world of difference...

    audio is a dangerous thing when left to the volunteer world.....

  5. #5
    Senior Member SC358's Avatar
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    audio is a dangerous thing when left to the volunteer world.....
    ...ahem... inexperienced volunteer, I'd say .
    SC358
    Relationships are based on compromises - behavior accepted is behavior repeated.

  6. #6
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    ...ahem... inexperienced volunteer, I'd say .
    Do you mean the (this would be myself muttering in my sleep) "OH, NO, OH HELL OH NO THEY DIDN'T, OH NO, THEY DID, QUICK, GRAB ME TWO MICS AND GET MY METER!!!!" type volunteers?
    'I think my intimate relationship with electronics started as a child when I was playing with a screwdriver and a wall plug, Doc, and...'

  7. #7
    Senior Member SC358's Avatar
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    Yup!!! Or - Holy crap! Who's bright idea was it to do it that way?? You should do it this way....
    SC358
    Relationships are based on compromises - behavior accepted is behavior repeated.

  8. #8
    Damn, this could be a separate thread, no? The "you should do it this way" V's are the ones who know everything there is to know about home stereos built in the 70's. No, I will not laugh at them. I will, pity them, and comfort them, untill I can get SOMEONE ON THE PHONE TO COVER FOR ME FOR A FEW HOURS! (may they be blessed anyway,AUDIO HEATHENS THAT THEY ARE!).
    Last edited by penniesfromheaven; 18th Nov 2007 at 03:11.
    'I think my intimate relationship with electronics started as a child when I was playing with a screwdriver and a wall plug, Doc, and...'

  9. #9
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    Quote: SC358
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    ...ahem... inexperienced volunteer, I'd say .
    I've seen some 'experienced' volunteers that still lack a clue... one guy I know goes to big worship-arts conferences every year and attends workshops, but still knows jack....

  10. #10
    FIRE HIM...(just kidding.. I've been that guy before. Give him a chance if his heart is in it)
    'I think my intimate relationship with electronics started as a child when I was playing with a screwdriver and a wall plug, Doc, and...'

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