Subwoofer Choice

Just guts feeling: size matters. Even if 2x xx diameter might have the same surface area (or moved air volume) than 1x yy (or to show my point, 20x 5 inch woofers same as (haven't done the math) 1x 18" woofer), I just don't think a bunch of 5" can naturally produce the 50 Hz and below (down to 20) that an 18" can. Therefor IMO, 1 big is better than 2 small.  

This is coming from years of listening to towers with sidefiring 10", plus 2 active 12". Then I got my first REAL SUB (in a humongous vented box, driven by an ICE sub amp), and the world changed. I ran the towers as 'small' speakers in my 5.1 system, and now the tiny (5x80W) receiver sounded SO much better. 

I am now using an 18" in a sealed 4.5ft3 enclosure, driven by the same B&O ICE design amp. Just LOVE it. Once you heard real SUB (the stuff "down there") there is no going back. My Nautilus 804 are said to have great lows. And they do. But so much better if aided by the 18 incher. 

@bound4h Congrats on the S/812 purchase, Bassline Blue high level connection is an upgrade from stock cable.

+1 for looking at Rythmik.  Several years ago I went with the servo-controlled, sealed F12G with the paper driver for the speed/musicality components listed above.  It marries seamlessly with my Magnepan MMGs when dialed in properly.  I think anyone looking for a sub is doing themselves a disservice by not looking at the Rythmik line.  

@james633 

No, unfortunately the Michi X5 does not contain any sort of crossover controls but does allow for some simple tone controls (treble, bass and that's it).  Not sure if those controls apply to the high level outs only?  

So, as a more general question, is it true that because i have an integrated that I cannot use a separate crossover at all?  I believe yes is this answer, but wasn't sure if your comment was in response to the CR-1 specifically.

@hartf36: Yes indeed! Now you may want to check out the OB/Dipole Sub offered in collaboration between Brian Ding of Rythmik Audio and Danny Richie of GR Research (as is your F12G). It uses two or three (your choice) of the same paper cone woofer as found in your F12G, but the driver electrically optimized for open baffle use. The woofers are mounted in an open baffle "frame", the sub therefore propagating sound in the same manner as dipole loudpspeakers---from both the front and rear of the drivers. The ultimate sub for Magnepans (as well as all other dipoles)!

A dipole woofer system has been under development at Magnepan for the past few years, and will eventually be offered in both the upcoming "30.7 For Condos" model and as a stand-alone sub for use with the company’s other models (as well as those of all other companies). It is not, however, an open baffle design, merely a dipole. Numerous woofers mounted in a sealed enclosure, drivers firing forward and backward. Can’t wait to hear it!