Audio
Impedance (Ω)
01 — Definition
The opposition a circuit presents to alternating current, in ohms — resistance's cousin, but one that changes with frequency. A pro microphone sits around 150–250 Ω, and should see a load of at least 2 kΩ. The bridging rule: for a flat response, load impedance should be 10× the source impedance. On the loudspeaker side, nominal impedance (4Ω, 8Ω, 16Ω) sets the load the amplifier sees and the power it delivers.
02 — In the field
Plug a high-impedance guitar into a low-impedance mic input and you kill the top end — go through a DI. And a 4Ω load on an amplifier rated for 8Ω minimum is overheating guaranteed.