NS-SP1800 Multimedia Home Theater Speaker System has Advanced Yamaha Active Servo Technology (Advanced YST), this 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.

Yamaha - 5.1 600 W Home Audio Speaker System

$149.99

NS-SP1800 Multimedia Home Theater Speaker System has Advanced Yamaha Active Servo Technology (Advanced YST), this 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.