Impedance for amp and speaker combo

Question

I have a set of speakers rated at 6ohms impedance and handle 75W, but my amp says 8 ohms or more. Does this mean I need to buy a 2ohm resistor for each speaker? Or just not turn it up loud? Or play it in mono from the same channel :'(?

Basically, to make this question as broad as possible, can I get a really good explanation of the relationship between impedance and power and what that means for pairing an amp to speakers? I understand the physics but someone else might not, so some explanation of that would be good.

Thank you kindly.

Answer 1

The lower speaker impedance would cause a larger demand from the amp, but that's not a huge mismatch, and not likely to damage anything if you stay in normal bounds. No one can guarantee anything, but this seems fairly safe to me.

Remember too that speaker impedance is a nominal value and will vary a lot over the range of frequencies. If you can get an impedance graph vs frequency you might find that at the points you're demanding the most power, the impedance is actually greater than 6 ohms.

You could also try this Q on Electronics SA, as it's pretty specific technically.