The Rockville REQ215 is an extremely high quality professional rack mountable equalizer. This is a 2 channel equalizer with 15 bands per channel. The main focus on this was sound quality and making it rugged and tough. We wanted to build a professional product that will instantly make a good speaker sound better, and after months of testing we know we did it! This is a 2/3 octave graphic EQ which gives you the ability to select between 0-6 dB or 0-12 dB cut, or boost. It boasts a frequency range of 25 Hz to 16 kHz. This graphic EQ also has a low cut crossover filter switch, with status LED, that helps remove rumble from mics. Another great feature is the bypass switch, with LED indicator, which is very convenient when doing sound checks. This graphic EQ also has a low cut crossover filter switch, with status LED, that helps remove rumble from mics. Another great feature is the bypass switch, with LED indicator, which is very convenient when doing sound checks. We added a sub output with frequency controls (30HZ - 200 HZ) which is something that we see a need for. Many brands for some odd reason do not give you a sub output and sub controls. We made sure to include this important function. If you want the best sounding EQ on the market at a great price, then we highly recommend you try out our REQ215. If you are unsatisfied with the quality we will give you a 90 day money back guarantee including return shipping! Features: The Rockville REQ215 is a Dual Channel 30 Band (15 bands per channel) rack mountable EQ Dual channel (15 bands per channel) Switchable 12 Band or 6dB boost/cut range 80Hz 24dB low cut filter 2/3 octave filter sets 25 Hz to 16 kHz effective equalization range Constant Q filters Output level LEDs (-12 to +17 dB) Low cut filter switch with status LED XLR inputs and outputs for balanced operation Bypass switch with status LED Balanced XLR input/output Subwoofer out