EMB - Eqb75 - Dual 10 Band Stereo Equalizer With Spectrum display. Extra instruction applies: 1. If you dont see the light up show up in the unit, please do the following. A. Increase your bass sound of your music to a higher frequency B. Raise up the low frequency to higher range. C. Lower your high frequency to a lower range. D. Make sure you maximize the volume in your receiver 2. If you hear humming noise, please do the following. A. Unplug the unit and make sure the unit is securely ground and snug tight in the power adapter B. Lower your high freqency to a lower range. C. Make sure you use twisted shield RCA cable, lower quality cable will have noise interference that will cause humming noise