Practical Recording Techniques, 7th Edition

Appendix C Impedance

Impedance is one of audio’s more confusing concepts. To clarify this topic, I’ll present a few questions and answers about impedance.

What is Impedance?

Impedance (Z) is the resistance of a circuit to alternating current, such as an audio signal. Technically, impedance is the total opposition (including resistance and reactance) that a circuit has to passing alternating current, measured in ohms.

A high-impedance circuit tends to have high voltage and low current. A low-impedance circuit tends to have relatively low voltage and high current. High Z is about 10 kilohms and up; low Z is about 1000 ohms and less.

I'm Connecting Two Audio Devices. Is it Important to Match their Impedances? What if I Don't?

First, let’s review ...