MM Productions Ltd - Questions and Answers

Questions and Answers

SPEAKERS and AMPLIFIERS

How do speaker impedance values work?

Quite simply, The speakers impedance is a measure of how much it will resist the flow of power from the amplifier. Most speakers are rated at 8 ohms. The important thing to remember is that the more speakers you run off a single channel, the less the total resistance is.

The formula for this is:

where Rtotal is the total resistance seen by the amplifier, R1 is the resistance of the first speaker, R2 the resistance of the second and so on up to Rn which is the resistance of the nth speaker.

If you run two 8 ohm speakers off one amp channel, the combined resistance reduces to 4 ohms. Add a third, and it reduces to 2.6 ohms. A fourth, and it goes to 2 ohms. So, you must be careful when running several speakers that the amplifier will run power into 2 ohms. If it wont, you may damage the amplifier.