-> What is involved in creating a bridged mono output? Is it simply a matter 
of
-> tying the two positives together (which really
-> doesn't sound right to me), or is there more to it than that?
More to it than that :-)
However, depending on the amps "design" it -usually- can be done. You need to
provide one input that is "normal" and one that is "phase inverted", then you
can go between the two hot outputs. Many crossovers, preamps, boards have 
phase
inverted outputs available on them, or what I did for some of my amps (long
ago) was to purchase a little pcb from the Hafler corp. that was/is used to
provide mono bridging for some of their older amps (like the DH-500, DH-200
etc.). It is small, has a wide range of operating voltage so it can "tap" 
nto
almost any piece of equipment, and provides a phase inverted output. I just
mount it in the equipment, wire it up with a mono/stereo switch and voila..
Caveat - some amp designs are not bridgable, usually due to -existing- 
bridging
internally; the simplest "rule-of-thumb" is if the amp's speaker outputs are 
at
TRUE ground referanced to each -other-, v.s. "floating".
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