The Yamaha NS-SP1800BL 5.1-channel home theater speaker package is a low cost, convenient way to enjoy the full benefits of 5.1-channel home theater sound. The NS-SP1800BL features advanced Yamaha active servo technology (Advanced YST) is a unique system in which the speaker and amplifier work together to cancel out impedance so the speaker unit has a perfectly linear motion. Advanced YST helps to ensure the highest levels of sound pressure and overall performance.
