Low-Frequency Optimization Using Multiple Subwoofers

At low frequencies the listening environment has a significant impact on the sound quality of an audio system. Standing waves within the room cause large frequency-response variations at the listening locations. Furthermore, the frequency response changes significantly from one listening location to another; therefore the system cannot be equalized effectively. However, through the use of multiple subwoofers the seat-to-seat variation in the frequency response can be reduced significantly, allowing subsequent equalization to be more effective. Three methods to reduce seat-to-seat variation are described, including a novel approach based on simple signal processing. The desired result in each case is to allow the system to be equalized over a seating area rather than just one seat. Results are shown for several listening rooms.