Change nominal impedence of driver?

[toenail]

Is there a practical way to change the nominal impedence of a speaker, in this case from 4ohms to 8ohms?

[markw]

It's in the design of the driver from day one.

[toenail]

In that case, another question. I have a set of 4ohm speakers that I'd like to use temporarily as rear surrounds. Yamaha amp can handle 4ohm mains but recommends minimum of 6ohms for surrounds. If I'm not wailing on the amplifier, is it safe to run the amp in this configuration? Amp is rxv-450.

[poneal]

just don't crank it up. The yammy may go into protect mode if you drive it to hard. So go ahead and give it a shot.

[Kursun]

Is there a practical way to change the nominal impedence of a speaker, in this case from 4ohms to 8ohms?You have received some excellent responses. I may add: keep the amplifier well ventilated. It should have enough breathing space all around.

I will also add that some speaker parameters are not well understood,
especially:
a) Power handling and
b) Impedance of speakers

The impedance of a speaker system is 4 or 8 Ohms just because its manufacturer has decided to call it as such. One speaker manufacturer's 4 Ohm speakers may equal to another speaker manufacturer's speakers rated 8 Ohms. Single figure Impedance specifications just give you an idea whether the speaker has a "lowish" or "highish" impedance curve.

[pelly3s]

you could always wire a 4 ohm load resistor into it in series and it will bring you to 8 ohms. probably not the most practical way but hey it works