Our Slide-Type hi-end impedance matching stereo volume control is designed for attenuating the volume of one to eight pair of speakers connected to the same stereo amplifier. The slider mechanism is detented with 12 steps of attenuation, thereby providing the cleanest pass-through of signal from amplifier to speakers.
Most amplifiers are optimized for 8 ohm speakers but are stable down to 4 ohms. As you combine multiple speakers in parallel (+ to + and - to -) to the same amplifier, the impedance level drops. By simply adjusting the location of two shorting bars located on the circuit board, the impedance can be adjusted in multiples of X1, X2, X4, and X8. A properly planned impedance matching scheme utilizing these volume controls, will bring the impedance back up to a safe level for your amplifier.
Download the Owner's Manual for diagrams and complete instructions.