Feedback in your PA

    I recently acquired a Bose L1 model 2 with B2 and Tonematch.

    I struggled last night with some feedback issues. This will be based on numerous things such as placement/vol/blah blah.

    That being said, I started to think a bit outside of the box.

    I found this app for my Android phone called Audio Spectrum Monitor.

    This is the most accurate app I've found to listen to and display frequencies.

    I wanted a RTA app to help me find offending feedback frequencies. This is it.

    As an example, I hooked a mic up to my Zoom L-12 mixer/recorder, and stuck the mic in the woofer of my Yamaha HS80M monitor.

    The app showed feedback around 100hz.

    I then dialed that freq range on that input on the L-12 and lowered the low end. Boom! Feedback gone!

    I then repeated the experiment with the mic in the tweeter.

    1000hz, same method and feedback gone!

    The app shows the frequency along with the note, therefore 440 = A.

    That's how the Bose works.

    Winning!


    So... lesson for me is that if you are gigging, or even in your regular practise space, you can use this app to find the nasty offending feedback frequencies and knock them out by yourself, or at least tell the sound guy where the freqs are.

    :)

    A RTA as a mobile app makes a lot of sense.


    The tuning solution I use in my studio is actually something designed for live sound use, the DBX DriveRack PA 2. First it tunes the room with a test signal (a couple of quick blips rather than the minutes of white / pink noise venue customers had to endure in the old days of RTA only solutions) and applies an 8 band parametric. However, it also has a built in feedback suppression system. It sits between your mixer output and speaker inputs in the rack.


    I seem to recall a number of other rack mount feedback suppression systems out there as well, i.e. it catches and eliminates the feedback in real time rather than having to dial it in for a specific frequency. Don't know if they do room tuning or not.


    Of course, none of this is as easy on the wallet as a free Android app! :)


    Edit: Corrected the name, which I had wrong. Here's the unit I was talking about:

    https://www.amazon.com/DBX-Dri…016OVUINM/ref=sr_1_1_sspa

    Kemper remote -> Powered toaster -> Yamaha DXR-10

    Edited 2 times, last by Chris Duncan ().

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