Variable Attenuator adjusts from 0db (no attenuation) to infinity or maximum attenuation. This is a 2 channel device with a separate adjustment for each channel. Ideal for applications where the source has very high output and the amplifier's volume or gain control must be set very low. This is a passive device so there is no noise or distortion (transparent to your system). IF YOU WANT ISOLATION FOR SPEAKER LEVEL SEE "SPEAKER LEVEL CONVERTERS".