Auto Audio Question

[Eagle]

Cleaning out the basement, I came across a pair of new-in-box Radio Shack 8" woofers I had bought many years ago to repair a set of bookshelf speakers. Never did it because I changed over to larger floor boxes.

These speakers are rated at 8 ohms. Am I remembering corectly that automobile audio systems use 4-ohm speakers? If these speakers were used in an auto system with, for example, a Pioneer 4x25 watt receiver, would they work? Would it damage the receiver, or just use a bit more power to achieve a particular volume level?

[5-90]

You are correct in remembeing that impedance for autosound speakers is 4 ohms. I think there is a way to impedance-match stationary 8-ohm drivers to 4-ohm auto circuits (tho I don't remember how offhand - power handling is an issue) and I have seen subwoofers for autosound with 8-ohm voice coils, so some amplifiers will probably tolerate them as well.

More research would be indicated before I could green-light 8-ohm speakers directly to your head unit, tho...

5-90

[Lou]

....or just use a bit more power to achieve a particular volume level?
I think that's pretty much it.

It should be safe to to hook them up to the head unit.

The impedance of a speaker actually changes depending on the frequency applied to it. So, a 4 Ohm speaker isn't always 4 Ohms -- it varies up and down.

If you wire them in parallel, that will get you the nominal 4 Ohms.

[Darky]

I have no technical expertise, but I've run a pair of house speakers in my car before. They were rated at 5-140 watts RMS and my stereo put out 50x4 RMS. They worked good, but nowehere near as loud as when hooked into the receiver at home. I only used them for about 7 hrs in my car. I was moving them from AZ to CA and had the wires run for a different set of speakers, so I swapped them...