Subwoofers for Magnepan 20.1s?

Marty You confuse crossover cutoff with frequency range, [so sub is not locatable bass is non directional under 75hz] When running 1 sub best to run under 75hz or so. Otherwise you will hear where subs located. Also the driver you mentioned is a hi-excursion doughnut surround type, these need massive power and are only designed for sub bass use mostly for HT. Heck I have designs that use 12in woofers up to 1500hz and I'm not alone. Most 15in-18in up to around 1000hz, 12in 1500hz or so. 31.5in woofer 250hz is no big deal. I will not offer any doughnut hi-excursion design for they do not do proper justice to music. These designs need floor,corner boundary reinforcement,and massive power to generate bass. A 31.5in woofer does not. The doughnut drivers are jumping about when they produce bass frequencies the 31.5in has only 2.3mm xmass. It hardly moves allowing much detail and wonderful transient response a key to great sound with music. So no problems running large drivers in bass frequencies. This is what they where designed to do.

John,

The crossover point deteremining "locatability" was NOT the issue. The reason I added the note in my original post about "even in stereo" was because I asked that very question. Rather, I'm sure that you hit it with your descrition of driver type and suitability for use only in the low bass region.

That's why I advised any buyer to determine the suitability of any sub with an extra large driver for use at higher frequency. I didn't recommend avoiding large drivers in subs, just double checking for enough flexibility to deploy as desired. I sure wasn't aware, however, that a 31+" driver had such flexibility. Thanks for the info.

As to suitabilty of such a "doughnut" driver for music, I'm working on that right now. It sounds different from my previous (Velodyne 8" x 2) subs - that much is clear. So far, I'd probably have to disagree with you, but my experience to date is too limited to take a really informed position. When I've had some more time with it, I'll post further.

Marty

John,

One further thought:

A lot of folks are going to be limited by cabinet size at SOME point - probably well before they could consider a box housing a 31.5" low excursion driver. The ability to accomodate a huge driver with minimal excursion is a luxury unavailable to many (probably most) music lovers.

Your preference for trading off driver size for excursion may be 100% correct, but I suspect that most people are weighing 8" vs 10" vs 12" (maybe vs 15" drivers). Depending on any buyer's particular need for deep bass performance, their choices may therefore be limited to driver designs you'd prefer to avoid. This being the case, I'd still advise anyone to double check the recommended high frequency limitations of the driver (particularly if they're thinking 15") in their prospective subwoofer purchase, since most of the commercial subs out there seem to use such drivers.

Marty