Sir Terrance
I have been following this thread about the Machs this is my set up:

I have them hanging in the front of my garage powered by an old Pioneer 380 watt RX 531 and in the back i have a pair of Pioneer J825Q powered by another 380 watt Pioneer RX 1220. Researching this site i read where the Machs are best driven by an old Pioneer SX 1980. But i like the digital stations and the fact that they are both controlled by the same remote.
The only problem is that i cant crank it up over half way without it distorting they don't seam to be balanced and i really don't feel the base as being described. Is it my receiver? do i need more watts?. Or maybe i need to get them checked out like you did. Help