Subwoofer for Magnepan 20.1s Yes/No/Why?

Have you measured your in room frequency response? Whether or not you need a sub really depends on what your measured output is in the bass area. Your room will determine whether your drop off at 80hz, 60hz, 40hz or 20hz.

I have full range speakers, but my room kills things at 80hz, save for a giant 35hz peak. The only thing that works in my room, is to high pass the speakers to avoid the 35hz peak, and to place a sub behind the listening chair, and then EQ the sub.

Your speakers are apparently -3db at 25hz, but again, it's all about what you get in room.

You have nothing to worry about with coherence, etc, but successfully integrating a sub pretty much requires being able to take RTA measurements.

I found the SWARM by Audio Kinesis (Duke LeJeune) to work very well in evening out bass modes and giving me some low slam without mucking up the bass. From his website:

"The Bass System


The main obstacles to natural-sounding bass reproduction are the inevitable room interactions - which impose large peaks and dips on the bass response. By using multiple subs spread asymmetrically around the room, each sub will produce a unique peak-and-dip pattern at the listening position. The combined average of these unique peak-and-dip patterns is much smoother than any one of them would be, resulting in more natural-sounding bass with excellent pitch definition. The Planetarium bass system also avoids the subjective slowness of most subwoofer systems by taking room gain into account. Typical in-room extension is to 20 Hz, but the main advantage of this approach is bass quality, not quantity.


Planetarium Alpha and Beta modules available separately; bass system sold separately as "the Swarm"."

Hi Powderdocter, I have had my MG-20's for over 15 years, along with hearing numerous 20's and 20.1's setup in many different systems. Before you spend money on subwoofers I would recommend at least to possible changes that would dramatically effect the performance of your 20.1's to a much higher level:

1) I have never heard 20's or 20.1's really perform up to their ultimate ability without biamping with an external x-cross over. The whole speaker is effected, however the bass extension/power on the bottom end also really becomes much better.

2) Read my GON review of the Mye Sound stands for all the details regarding the astounding impact on the overall sonic performance of my 20's, along with the best bottom end kick I have ever heard from my speakers.