HU powered sub?

[cmk05]

Another question for the stereo gurus...

Could an 8" sub be powered from the rear channel outputs of a head unit?

Still working on a home boombox made with car components and am wondering if there's a way to add a sub without adding an add'l amp.

Could an amp not explicitly bridgable be bridged to power a single voice coil sub?
What if both L and R outputs were combined at a single driver? Can this be done, or will there be a problem with load, etc?

[Steve02Si]

a select few head units have bridgeable speaker outputs on the rear channels to drive a moderate sub. I know Pioneer does this on some of it's units, not sure who else. As for amps that arent bridgeable, that's rare. pretty much every amp out there is capable of combining it's channel pairs into a mono bridged channel.

[cmk05]

would i blow anything up if i plugged both a left and right channel into a single voice coil driver?
would the amp still 'see' a 4 ohm load?

[Steve02Si]

if you parallel two channels to one coil, you'll probably smoke something. when you bridge 2 channels of an amp on a 4 ohm speaker, each channel technically sees 2 ohms.