Let’s talk about managing feedback in your karaoke DJ equipment.  Because feedback is a possibility whenever you have an amplifier, speaker, and microphone, you can’t ever completely erase the threat.  Unintentional sound is picked up by the mic and it begins looping through your gear at a specific frequency and that’s all she wrote.  I think karaoke DJ set ups are harassed by feedback more since there are more than one omindirectional wireless signals being used and constant adjustment of microphone volume.

In a perfect venue, every feedback challenge would be solved with ideal sound equipment placement.  Reality isn’t quite so ideal and a mobile KJ will have to compensate for all kinds of headache inducing acoustic variables.  You get echoes, funky standing waves, and the management restricting your equipment placement with weird limitations on your rig.   What should you do except adapt?

Ideal solutions is to own a dbx DriveRack PA to auto-pink each space.  It’s a heck of a way to lighten your rack set up, too.  The DriveRack PA in a single rack slot replaces the graphic equalizer, limiter, crossover, and feedback destroyer.  Down side is the 600 dollar unit is a little expensive for many DJs.

Ringing the room is a less expensive, manual method of preventing feedback.  This is no more than the correct application of your 31 band graphic equalizer and I bet you already have one of those.  It takes perhaps fifteen minutes to do as soon as you’ve gotten the hang of it, and it is an efficient method to minimize feedback if you are able to manage the small modifications for the acoustic variables between empty room and a room filled with bodies.

Begin the process by placing your speakers in the best possible locations for preventing feedback.  Next, power your amplifiers up, keeping the master gain at zero.  Put every equalizer control in the middle at “flat.”   Check because your VocoPro player might have equalization features as well, so set those to center, too.

Start ringing out your venue by turning on the primary microphone and getting someone to sing a dull track for you.  Feedback is going to occur at some point as you gradually turn up the overall volume, so go in small increments.  You will find that your particular set up owns a peak frequency that is a typical issue for you during a ring, and sometimes that will be the first feedback you will get.

Go to your graphic equalizer and tune down the troublesome frequency.  Can’t figure out which frequency is the culprit?  Either get a spectrum analyzer or simply fiddle with those equalizer sliders until you find it.  Adjust down the slider that controls the feedback frequency range, yet if you can prevent zeroing the control out, that’s better.  You don’t want the quality of your sound to be ruined by distortion due to unbalanced equalizer settings.

Continue increasing the main volume and tuning out offending frequencies till you have as much gain you want.  In an average space, you might have to adjust up to eight bands.  If you continue ringing out the room beyond that certain point, you will either get :a whole bunch of frequencies shrieking; the already adjusted frequencies howling as you increase the volume; or the your sound quality gets really bad.  

To complete the process of ringing out the room, you give yourself a safety cushion by dialing the main volume down by 8-12 dB.  When you’ve done a ring carefully, you might produce as much as 10-12 decibel more.  You don’t want to increase the volume at the expense of a quality sound, though.  And you shouldn’t let any of your secondary volume levels in your machine karaoke set up creep up higher than that main volume level you’ve just rung out.  And that’s the gist of ringing out a venue to minimize feedback.