What is best sub to match with Magnepan?

What is it about the Sunfire that's "not doing the job" specifically? Are you having integration issues of some sort? I ask because I was able to integrate 10" driver Sunfire subs very successfully with Maggie 1.6's. The Sunfires were not last word in performance by any means, but as long as the level, phase, and crossover points were set properly, I never felt they called attention to themselves and definitely helped to fill out the lower octave. Is your system two channel or are there other speakers in use for Home Theater functions?

I don't like or use subs (I say upgrade the speakers/amps, but understand may not be feasible/practical & you may really like what you have) but the rules I have always heard (as subs are so tough to integrate properly) is (1)buy the most expensive sub you can and (2)get one with an included bass amp as running a sub off your amp is pretty much a mess. That bottom bass octave is the toughest to get right and it will cost you. There is music down there! Remember, good bass frames your soundstage.

(you may not be liking the bass because if your amp but I do understand the maggies can be a little bass shy (the 1.7s)).

Good luck.

Here's a thread from a few months ago on the same topic:

http://forum.audiogon.com/cgi-bin/fr.pl?cspkr&1382555455&openfrom&1&4#1

How about the Magnepan DWM bass panel? With a frequency response up to
7Khz it's certainly fast enough. True, it is more of a deep woofer (40 Hz) than a
sub, but that 40-60Hz boost will provide that little bit of missing foundation for
the 1.7s.

I just got a pair of 1.7s a couple of weeks ago too. I'm not using a DWM, but I
already had a pair of Mirage MM8s, which are *very* quick and lively. They are
9" cubes housing an 8" active driver & 2 passive radiators, powered
by a 1200 w peak class D amp. The diaphragms are very lightweight aluminum
and the surrounds are very compliant and allow for a good excursion. They also
have continuously adjustable volume, 0-360 deg. phase, and crossover from 50-
200 Hz (or none).

Audiovox/Klipsch shut down the Mirage division, but this same sub is still
available as the speakers.com/products/subwoofers/?sku=ESW-M8>Energy ESW-M8. I
have a pair of them positioned in close proximity to the panels, have the
crossover set to the lowest point (50 Hz) and added just enough volume to
flatten the bass down to about 36 Hz, but not so much to be boomy, thickening,
or otherwise intrusive.

I have a friend who's happy with an SVS SB12-NSD with his Maggies. SVS has a
45-day return period, and they pay shipping both ways. That's an attractive no-
risk way to see if you can get one to work for you -- go to www.svsound.com.