Hi Audiodreamer
I take it from the designation that the Energy sub is an 8" unit. A smaller driver definitely will not go as low as a big driver, however, it might be better for music. I used a 10" Velodyne with a 2 channel system and loved it, it may not go as low but it was quick, and could keep up with the music.
I see that some other Axiom user has a pair of Michaura M55s, which use the same 5.25" drivers as the M2 and M22s, but use the 3/4" titanium tweeter from the old M2, M1, Mzero speakers. For some reason, the M55s worked better for me in a 2 channel system than its slightly bigger cousins, the M22s. I have a paif of M22s in my garage system, (no sub) but I'll swap them in for a pair of M55s in one of my 2 channel systems and report back.
Axiom speakers are terrific and their sound quality/price ratio is excellent. There are other great speakers out there which rarely get the buzz they deserve. KEFs, Focals, Wharfedales and the EPOS speakers are really great and also provide some great bang for the buck especially in these times when we can expect even steeper discounts.
Good luck and welcome.
