You probably know that to transfer the most energy between a source and a load their impedance needs to match. That’s why a ham radio transmitter needs a 50 ohm antenna (at least, usually).

Is speaker impedance, which is measured in ohms, important? Plus, do you need to match speaker and receiver ohm ratings?

For that matter, what's an ohm? While impedance technically does matter, it's not quite as cut and dry as saying "speakers with X impedance should only be connected to receivers with Y impedance." ...