The power should equal the impedance rating for each of the speakers.
Some speakers require more or less power than others.
Power and Volume
Power output and speaker volume follow a logarithmic, not linear, relationship.
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It takes an increase of 10 dB to make speakers play twice as loud as before.
Some speakers must work a little harder than others to achieve a specific volume output.
Certain speaker designs are more effective than others in projecting sound evenly across open spaces.
Bigger rooms, greater listening distances, or less sensitive speakers demand more power from the source.
The former indicates continuous power output over periods of time, while the latter indicates output in short bursts.
Speaker specifications can also listnominal power, which is what the speaker can handle over periods of time.
