Impedance - 2 ohms and 4 ohms. What does this really mean when building a system?

[bamakin]

Can someone please explain to me what the difference is between the two. I know its the acoustic impedance but what difference is found when building audio system? Is it that higher ohms create lower temperatures in the wiring etc?
Sorry for sounding stupid here but if ya dont ask ya never know!

Thanks.

[chrisvr4]

http://www.prestonelectronics.com/audio/Impedance.htm

:)

[bamakin]

http://www.prestonelectronics.com/audio/Impedance.htm

:)

This is great thanks!!

[VR457]

Simply put, most car speakers are 4 ohms. If you connect two 4 ohm speakers in parallel, ie wire them to one output terminal of the amp then the amp will 'see' a load of 2 ohms. A lot of amps give out their peak power at 2 ohms. Specialist amps can go down to 0.5 ohms.

Sound quality wise it makes no difference. However, some amps might produce a harsher sound if the ohmage is dropped down.