Drew, it's unclear what you mean by "theatrical sounding", but it's certainly feasible to use two M22s or M60s for a center. They would be wired in parallel from the center channel output of your amplifier(no, that isn't the useless scheme referred to as biwiring, or "buywiring"), with two wires connected to the output terminals and one connected to each speaker. There's a probability that your 2600 could handle this lower impedance load without needing more amplification, but in any case it shouldn't be assumed that it can't.
