If you have an external audio interface (ie AudioBox, FireStudio, StudioLive, etc..) you would come out of main outputs.
If you don't have an external audio interface you're best bet is probably the speaker/headphone output (probably a 1/8" stereo output)
Signal path should be Computer/Interface -----> Temblor T8------> Eris E5's
The sub will take the low end, then use a crossover to only send the mid/highs to the E5's. That way your sound will stay as clean as possible.
Another thing I would recommend would be to make sure all equipment is plugged into the same power source / power strip. If you plug things into different outlets you're increasing the probability of introducing noise into the path.