The Peerless Superior Dynamic Sounds (SDS) Series provides the lowest cost/highest-quality woofers in the industry today. The SDS woofers are characterized by their very smooth frequency response all the way into the midrange, with low distortion and consistent off-axis performance. Applying the best in Danish engineering, but manufactured to be very affordable, these audio transducers are ideal for use in small surround sound systems and other hi-fi applications.