Hi Lloyd,
Since my Arrakis are true bi-amped speakers (with the Rockport external crossover), I run my 2 CH M1 amps in active bi amped mode. This allows me to use 1 M1 per speaker instead of 2 Siegfried’s per speaker. In active bi-amped, each M1 has 2 separate and independent adjustable global feedback and gain controls for each speaker. For the bass drivers of the Arrakis I use 60% global feedback and for the mid bass, mids and highs I use 0% global feedback. I did experiment with different feedback settings for the bass drivers and found that 60% gave me everything I wanted - especially incredible overall speaker control. Another advantage of using the M1’s is that with the Siegfried II’s, as you increase the global feedback (its has 4 settings for this) the gain of the amplifier is lowered (this is not the case with the M1’s). So in order to properly bi-amp each speaker I had to use the gain controls of the external Rockport crossover to keep the 2 Siegfrieds per channel in proper balance. With the M1’s this isn’t necessary and so the crossover is set to them “0” setting and just acts as more a signal pass through.
Wow and more wow. That is really fascinating and another great post to keep in the files for future reference. Thanks, Arnie. I really enjoyed reading about you and your system in The Audio Beat the other month. Truly great of you to share that with everyone...a lot to admire and learn.