Here's my situation: I have a Klipsch Promedia 2.1 system and the left channel died. The left speaker works fine when plugged in the right speaker output on the sub. Right now I have both speaker wires in the right speaker output in the sub so I get the right channel on the L and R speakers. Is it possible to play both the left and right channels on the iMac through the right channel so I at least hear everything from both channels?
Buy a mono 3.5mm audio cable, plug it in, you will have both output channels hard-mixed and played on both speakers.
If the cable on your speaker is non-removable, simply buy a 3 inch male-to-female one.
And if you can not find a cable like this, go to a shop that sells audio cables for guitar players and ask one to be made for you. You will hardly pay more than 10 bucks on such a thing.
Analog solution to a digital problem, YAY!