audio feedback from trumpet mic

Discussion in 'Trumpet Discussion' started by crowmadic, Apr 26, 2010.

  1. crowmadic

    crowmadic Mezzo Piano User

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    Short of turning down the gain on an amplifier, and standing away from the amp, what electronic gadget do you use to eliminate feedback from your trumpet mounted microphone? I'm editing this thread to give some specifics about the equipment i'm using. I hesitated to give this information because I know there will be objections to what I'm using, and advice about the equipment to use. But I just want to know what you're using to eliminate feed back. Here goes: I'm using a Digitech headset mic, modified to attach to my trumpet. The XLR mic cord is connected to a 10' 1/2" adaptor that is plugged into a Beringer V-Tone GMX 210 amp. We rarely have monitors, so I like to stay in front of my amp to hear what I'm doing when the guitar and drums get carried away. Of course I stay as far from the amp as I can get. A Channel and Effects pedal is attached to the amp also. I generally have the effects preset to Reverb and Pitch Shifter. Some day I'll get an acoustic amp, and cordless trumpet microphone. But for now this is what I'll be working with. In spite of the equipment I'm hoping to reduce or eliminate the feedback. Kcmt01 gave me one suggestion, and I'm hoping for more.

    Thanks.......... crow








    crow
     
    Last edited: Apr 26, 2010
  2. kcmt01

    kcmt01 Mezzo Forte User

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    Last edited: Apr 26, 2010
  3. trickg

    trickg Utimate User

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    You need a compressor/limiter. You can get all different types ranging from really cheap and inexpensive boxes like the Rolls CL 151, (about $90) which will probably get you where you need to go on the cheap, to rack units, to the FMR RNC, ($200) to well beyond that in price and functionality.

    Here's a link to the Rolls. It seems to me based on what I have read about the Rolls unit that it's main function is to help eliminate micrphone feedback on stage. I bought the FMR RNC recently, but for a different purpose. As a drummer, I'm getting a signal from whatever source I can to use as an in-ears monitor signal - in most cases I use a product called the ART HeadTap which allows me to plug directly into either a power amp or floor wedge monitor, and it takes the speaker level signal and attenuates it down to a line-level signal. I put the RNC (Actually stands for "Really Nice Compressor) in the chain between the ART HeadTap and the small mixer I use. Basically it's insurance that if for some reason my monitor feed gets overloaded, I don't ruin my ears.

    Since I already have enough noise in my rig due to some cheaper components, I didn't want to add even more noise with a cheap compressor. I get virtually no noise from the FMR RNC.

    In any case, a gate/compressor/limiter is probably what you're looking for. An equalizer might solve the issue, but I know what I suggested will solve the issue.
     
  4. crowmadic

    crowmadic Mezzo Piano User

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    trickg,
    Great reply. I'll look into that Rolls CL 151, equilizers are beyond my budget right now. But thanks to everyone that responds.

    crow
     
  5. trickg

    trickg Utimate User

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    You've piqued my curiosity about your sound setup. I have never played in a band where my signal from the mic was put into a stage amplifier - I've always gone into the main board and then out through the PA. Why are you setting it up like that? Is it due to a lack of monitors? Are you using the amp as a personal monitor AND going into the main board and out of the PA, kind of like a guitar player would, or is your amplified sound coming solely from the amp?

    Either way though, the Rolls piece will fix the feedback problem as long as you put it in the chain prior to going into the amp.

    You know what would be cool? Adding some guitar effects stomp boxes in there too! Haha!
     
  6. guyclark

    guyclark Piano User

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    Feedback in a PA system is caused by the sound coming from the speakers getting back into the microphone, and again out the speakers. The pitch of the feedback is dependent upon the delay between the speaker to the microphone. The delay within the amplifier, assuming a purely analog mic-preamp-power amp-speaker system would cause ultrasonic oscillation, and can be ignored for now.

    Now, if your microphone is mounted on your bell (like a TOA-KY mic such as I've used for recording purposes) you shouldn't have enough gain in the amplifier chain to get the positive feedback with the speaker unless you're standing right in front of the speaker stack.

    Upon re-reading your question, I see that this is exactly what you're doing. (whack with a rolled-up newspaper: Don't DO that!!!) If you really need to hear what you're doing so much that you have to stand in front of the main speakers, maybe you should investigate using a headset or earbuds, or even earplugs to cut down on the noise around you and you can then hear yourself more through bone-conduction!

    I would first try to move away from the speakers. Distance will reduce the feedback gain and possibly eliminate the feedback noise.

    Know what pick up pattern the mic has. It's likely a cardioid or hyper-cardioid pattern and thus is most sensitive in one direction, likely along the mic's axis. Be sure that this axis isn't pointed at the speakers. Aim the mic in towards the inside of the bell of the horn if it's not. This also should reduce the feedback system gain.

    Again, ear-protection will drop the level of the outside noise (music) and you'll hear yourself more through bone-conduction.

    Hope this helps, somewhat!!

    Guy Clark
     
  7. rowuk

    rowuk Moderator Staff Member

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    You limit feed back by setting the PA up with it. No sound engineer worth his salt doesn't "rehearse" feedback. Once they have found the limits, THEY EQ accordingly and keep the gain below those limits. There are NO surprises. It is not the musicians job to worry about that - other than to perform in the places "rehearsed and tested".
     
  8. guyclark

    guyclark Piano User

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    This is true! From the description of the problem, though I assumed (I know! ;-) ) that they were "self-engineered". People sometimes also move from where the engineer might have placed them, and that would mess up the engineers' settings.

    Now, I'm a recording engineer, rather than a sound guy, so I don't have to worry about these things, but I do love to stimulate feedback when I hear that slight ringing in the room, meaning that feedback is incipient! :evil: I'm truly evil!!!!ROFL

    Guy (666) Clark
     
  9. kcmt01

    kcmt01 Mezzo Forte User

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    The equalizer is for tuning the entire sound system, not individual instruments. Thanks for editing the original post. Don't worry about critics picking apart what you're using. You work with what you have. What you have now is an amplifier on your trumpet, not a real sound system. Our band got by with relying on separate amps for every instrument for a few months, but sooner or later you're going to have to invest in a mixing board, main amp, some sort of monitor system, etc. especially if vocals are involved. Since your band seems to have similar needs to ours, if you like, I can go into detail about how we started, what we upgraded, and what we plan to upgrade.
     
    Last edited: Apr 26, 2010
  10. kcmt01

    kcmt01 Mezzo Forte User

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    Sound engineer? You're kidding us again, right? I'm never sure if you're serious or sarcastic.
     

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