Connecting grounds on amplifier output

[perfknee]

I have an application where it would be beneficial to run only three wires rather than four to send a stereo pair of signals from amplifier to a pair of speakers. I'm considering simply jumpering the two ground wires together at the amps and at the speakers. I can't think of any reason why this would be problematic, but I just thought I'd post and see if anyone sees any significant safety or sound quality reason why this would be a problem.

The only difference from the normal 4 wire connection that I would forsee is that the ground wire could overheat more easily due to two signals rather than one passing over it, but my wire is sized such that won't be an issue.

Just now I thought of a possible concern: This amplifier (an old "Citation 5.1" 4-channel amplifier) is designed with a bridging switch (which I won't be using). Could this mean that the negative and positive terminals on half of the speaker terminals are actually reversed, such that there could be a short inside the amplifer between the positive of one terminal and the negative of the other terminal, to facilitate the phase inversion necessary for bridging? Hmm...

[perfknee]

I pulled out the instruction manual for my Citation 5.1 amplifier, and it says that to use bridging mode, one is required to jumper the negative terminals together. So I guess that's my answer: It's okay for me to jumper the negative terminals together for my non-bridged application.