How do I power 5 speakers w/4chnl amp?

First off, I can't buy another amp, I'm stuck with what I have for now. Current setup - Fronts are powered by the 2 front channels on the amp. Rears are powered by the headunit. The sub is on the rear right amp channel, and the rear left amp channel is open. The amp is an MTX 4244 (45rmsx4). The problem is that even with the front amp gain down, the rear speakers are just too quiet. I'd like to power all the speakers with the amp, how do I do this? Actually... these are the 2 methods I'm picturing, I just need some electrical advice on what's best and what the results would be - #1 Run both front and rear speakers off the front outputs on the amp. Leave the sub on one rear channel, or bridge the rears for the sub. #2 Run the front speakers on the amp fronts, the rear speakers on the amp rears, and have one of the amp rears ALSO power the sub. i.e. - left rear and sub on same channel in parallel. What would happen in either circumstance? I'm curious if my R/L output from the rear speakers would be different in #2 because of the amp on one of them. Thanks!

That's exactly how it's setup now, and I can't hear the rear speakers. The output difference between the fronts and the rears is enormous.

boostd4 wrote: Current setup - Fronts are powered by the 2 front channels on the amp. Rears are powered by the headunit. The sub is on the rear right amp channel, and the rear left amp channel is open. The amp is an MTX 4244 (45rmsx4). Thanks!

So this is incorrect, you've already bridged the two rear channels, no?  You're getting about 100w to the sub, right?  Should be able to at least hear it, even vaguely.

If so, I'd set the gains lower on the fronts, that's about all you can do for now.  Unless you run all four mains off the HU & bridge the amp entirely into the sub, if that's even an option.  Otherwise I'd disconnect the sub altogether for now & run the mains as 4x45 at full range (IE no crossover).  At least you'd have decent bass from the mains until you can get a new sub amp.  You need to be sending that sub at least 250w+ in that setup IMO.

Oh, wait - am I reading this right - you just want more output from the rear mains, not the sub?

If so, can you bridge the outputs on the headunit?  Most can, check your owner's manual.  That'll give you more output there.  Or run all 4 mains on 2 amp channels (2 ohms) - your SQ will degrade noticeably, but there will be more rear volume.

boostd4 wrote: That's exactly how it's setup now, and I can't hear the rear speakers. The output difference between the fronts and the rears is enormous.

That's the way it is supposed to be.

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Perhaps I need different speakers then. I lack midrange horribly and adjusting my EQ does nothing, really. Perhaps it's just something I have to live with. This system is in a 1992 Toyota MR2 Turbo. When it's parked, engine off, the sound really isn't too bad. When I'm moving with the windows down and the t-tops off, all i hear is the upper highs, and the subwoofer. My exhaust is a bit loud, and being a mid-engined car, the engine noise is a little higher than your average car. Was just hoping that the 4" pioneers in the rear could help with the mids if they were amped up. BTW, my sub is currently on ONE rear channel (not bridged) and it pounds just fine on 45W rms..   I find this strange too, as I've had other systems that sounded equally as loud with 200+W going to the sub. I guess it helps that the sub isn't in the trunk, but behind my passenger seat.