bridge a head unit

Can you bridge a hu from 4 x 22 rms to 2 x 44 rms?

nope. YOu'll burn it up.

Nope,  unless something says bridagble, it not.  All that bridgable means is simplistically, 1 channel, ch.A, drives a speaker with the positive terminal and another channel, ch. B, drives the speaker with the negative terminal.  So when bridged you get a bigger potential difference or voltage.  Thats not exactly correct but its the easiest way to understand it.'97 Jeep Cherokee sport

subs: JL 12w3v2 : RF 500a2 :

RF 1F capacitor

doors: 6" Diamond D361i -> RF 200a4

The rear channels on my HU are bridgable to two ohms. 70 watts x 1 @ 2 ohms. Pioneer DEH-P7400MP Paul

i think it is moreso crossing the 2 channels, kind of like putting a jumper between Ch.1(-)and Ch.2(+) 2000 Chevrolet S10

Premier DEH-P860MP

JL Audio XR650-CSi components

Boston 4x6 splits

JL Audio 10W3v2

Alpine MRP-M350

Clarion APA-4162

According to Pioneer's website the DEH-P7400MP HU can be switched so that the rear powered output becomes a mono subwoofer channel.  It changes the rear powered stereo amp into a mono amp that is 2-ohm stable and rated at 70 watts peak, so the "bridging" occurs electronically and not through external connections.  It looks like each rear speaker output will carry the same signal and it is stable to a net 2-ohm load (4 ohms on each output or 2-ohms on one of them.)  I've never even seen nor heard one personally, but it appears to be a nice feature for someone needing a bargain basement front-stereo main set plus sub solution.Support the12volt.com

Ahh, so on that output you woudn't bridge it, but connect a 2 ohm woofer to either the left or right channel, since it's mono. Gotcha. Paul