5. Amplifiers

The output signal from a mixer typically operates in the range of a few volts, which is not sufficient to drive a speaker. Therefore, the signal needs to be amplified by a power amplifier. Such a power amplifier can be a separate device, part of a speaker (active speaker), or part of a mixer (powered mixer). However, power mixers are somewhat rare nowadays. The combination of a passive mixer with an active speaker or a separate power amplifier is more common.

High-Power PA Power Amplifier

Powered Mixer

Active Speakers

In the case of an active speaker, there's no need to worry about the load capacity and impedance of speakers because the built-in power amplifier is perfectly matched to the speaker.

For a power mixer or a separate power amplifier, there are some important things to consider to avoid damaging the equipment:

• The power amplifier's output power should be higher than the speaker's nominal power handling, but not too high. A factor of 1.3 to 1.5 is a good rule of thumb.
• The minimum impedance of the power amplifier should not be exceeded. When connecting multiple speakers, you need to be aware of the total impedance resulting from the wiring configuration (series vs. parallel connection).

If you want to learn more about this topic, we recommend reading our Online Guide on PA Power Amplifiers.