I also have the Raven AC (one motor) and agree with Downunder.
I tried the Millenium may on and off. I like it on. I also tried the mat with the felt side up and the smooth side up. Both work well however I think this is where it becomes "fine tuning" your system. This is where, depending on your speakers and amps, you can play around.
On another not, a record clamp also made a difference in the tuning of the overall sound.
Rick (RWD)
I tried the Millenium may on and off. I like it on. I also tried the mat with the felt side up and the smooth side up. Both work well however I think this is where it becomes "fine tuning" your system. This is where, depending on your speakers and amps, you can play around.
On another not, a record clamp also made a difference in the tuning of the overall sound.
Rick (RWD)