5 years ago, I bought the Axiom Epic 80-500 system (5.1 with a 500w sub, 2- M80's, 2-QS8 surround, 1-VP150 center) . The sub has been nothing but trouble. It is very boomy no matter how I adjust it or where it sits. My solution has been to just keep it at a very low volume, I have wondered if there is just something wrong with it because reviews all say it sounds great. but this is the least of my issues, a year after purchasing, the sub just stopped working so I called Axiom and was told the spade connectors had probably come loose from the speaker terminals inside (A known issue), which ended up being the cause. After that the connectors again came loose, so many times I lost count. Problem is that you just cant tighten them too much without the terminal twisting on the speaker and then pulling on the soldered wire underneath that leads to the voice coil. Another year later, I started having problems with the trim and crossover controls on the sub woofer, there would suddenly be no sound from the sub, until I turned the control knobs back and forth a couple times and would then start working again (Cheep controls). It was just too much trouble to keep this thing working so I just unplugged it and besides it really never sounded that great for music anyway. I did recently email Axiom support thinking maybe they had some sort of a solution like maybe a new amp or a speaker terminal kit with lock nuts or something, they never even replied. The M80's have very clear sound but are a little bright. I can usually compensate with the EQ settings on my preamp and fortunately I have presets. I was thinking I could correct the brightness by altering the crossover or adding some volume control for the mid-range and tweeters but maybe that will be my next project.
When I bought this system, Axiom recommended a Sherwood Newcastle amp with 140w per channel, I ended up buying a Yamaha surround amp that was also 140w x7. Recently I bought a pair of 1000w mono blocks from Emotiva, to run the front speakers, was a considerable improvement thru the entire listening range, I hear lots of new sounds, better detail plus more of a punch. I think that Axiom should tell customers up front that you really do need some power to realize the full potential of these speakers, 140w is OK but 1000 is way better and when your spending that much money... If I had it to do again, I would probably keep shopping or build something myself. They are reasonably priced and I suppose "you get what you pay for".