How do I get the "most" out of a speakers that are rated for 12 ohms?

Your amplifier should be able to make about 150 watts at full power on that speaker.

Why would that be, Ralph ( @atmasphere ), given that the amp is presumably solid state, and is rated at 125 watts into 8 ohms and 200 watts into 4 ohms?  Wouldn't its max power into 12 ohms be significantly less than into 8 ohms?

Best regards,
-- Al
 

My amplifier is rated at 125 wpc @ 8 ohms, 200 watt's @ 4 ohms.

I would infer from this that the amp is solid state. Consequently, depending on its design its maximum power capability into 12 ohms could very well be not much more than 2/3 of what it is into 8 ohms. But as Bob noted above that is almost certainly not an issue given the efficiency of these speakers.

Also, while the resistors will increase the amount of power that is put out by the amp they will not increase the amount of power that is delivered to the speakers. The additional power will simply be consumed by the resistors themselves.

Also as Bob alluded to, I would expect the resistors to be useful mainly in the case of some tube amps. In those cases providing the amp with an 8 ohm load might provide sonic benefits by optimizing the loading of the output tubes and output transformer. Also, the resultant flattening of the impedance curve whoopycat referred to is most likely to be beneficial when the output impedance of the amp is a significant fraction of the impedance of the speaker. Which is almost certainly not the case when a nominally 12 ohm load is presented to a solid state amp, and is most likely to make a difference with **some** tube amps having particularly low damping factors and correspondingly high output impedances.

Regards,
-- Al