Lets you compensate for different rooms to always get a perfect sound. With +/-12dB of equalization over five bands (70Hz, 150Hz, 500Hz, 1kHz, and 4kHz). Its filter circuit is specially tuned by lowering the 'Q" and enlarging the bandwidth of each frequency. The result is a reduction of phase cancellation at crossover points, improved tonal character, lower noise, and increased tonal variation without peaking at any particular band. Five bands of +/-12dB of equalization