Tri-Wire

This is using the same Power Amplifier but using individual speakers cables to the loudspeaker Passive crossover. The bridging links at the rear of of the speaker are removed.

What is the benefits of this?

All conventional loudspeaker drive units are reciprocal transducers – they work as microphones too. When a drive unit diaphragm is caused to move, by application of current or by external force, it generates a small voltage in the motor of the driver which is ‘returned’ to the electrical input. This returned signal is the back e.m.f.

The back e.m.f. can only be removed if it sees a short (zero ohms) back to an amplifier with a (near) zero ohm output impedance. With a crossover and cable between the drive units and the amplifier back e.m.f. will always be a problem.

The most common approach to reducing the impact of back e.m.f on the playback system is by multi-wiring, Bi-Wire, Tri-wire, Quad-wire...

Removing the link plate from the crossover and running multiple cables to a single amplifier keeps the back e.m.f. of each driver separate until they reach the amplifier terminals.

This allows the amplifier to better damp the back e.m.f. of each drive unit without polluting the signal seen by the other drivers in the system.

Multi wiring by no means eliminates the deleterious effects of back e.m.f. but it does reduce them.

Tri-wire Example