An exceptional piece of acoustic design, the A225-1 sub-woofer/bass extension is equally suited to use as a mono sub-woofer in a surround sound application or as a bass extension in a stereo system. Designed to work in harmony with the A225-1 Sub, all PSI Audio ‘A’ series speakers feature a frequency response roll-off function that, when combined with the A225-1 Sub, extends the frequency range down to an incredible 28 Hz, whilst maintaining a flat response. The two powerful class G output stages feature PSI Audio‘s unique “AOI” output, giving the A225-1 an unprecedented impulse behavior.