Subwoofers for Magnepan 20.1s?


I used Granite Audio's Ultimate Low Bass CD and my 20.1s go to 25Hz at -10dB and my room is 16x26x10 (speakers approx 6ft from back wall and 3.5ft from side walls on ends). I can get -6dB in the 29-33dB range and then it is pretty flat with a slight drop in the 50-60Hz range. I am not a bass fanatic, but on some recordings, I wish I had some further lower bass extension without becoming unnatural sounding/boomy. I know HP likes Nola Thunderbolt subs with the 20.1s. Has anyone tried them or any others? Other system components: Pass X250.5 amp and Xono phonostage, Audio Research Ref 3 preamp and Ref 8 CD player, VPI superscoutmaster reference turntable/10.5 tonearm, Dynavector XV1S cart.
powerdoctor
You didn't mention price but with Maggies,Quads,NL's without built in subs you have a need for speed.You'll be happier if you give up octave or epth for transparency.I have been fan of REL's older series (or a spin off company MJ Acoustics) because they used multiple drivers to equal one large plodding sub which is fine for HT but not transparent speakers.Maggie themselves say "Don't go larger than 8" woofer" because they know you might shake the foundations with a Velodyne,JL,or other monster but not get neutrality that blends.I have not heard it but read review of TBI Magellan VII one amp/x-over double box system but 6moons said it was fast and neutral.You might want to check out Martin Logan and though head to head they are supposed to be more like a HT sub than REL they are deep and have multiple drivers for speed.Add a Velodyne SVS external DEQ (not expensive flip it easily if you want) would be last tip.Might improve outcome.But go for transparency,speed resulting in transparency.Now I am going to read about the Nola myself!!!!!!
Cheers
Chazz
1. In my experience, I believe the JL subs would work fine. I'd go for the 10 or 13 inch models and use two.

2. JL Audios built in software for room equalization works great and makes it easier to blend the subs with Maggies.

3. Plan on purchasing a seperate external crossover like a Bryston or equivalent. I'd find one so you can rid yourself of the Maggie passive crossovers and use the electronic crossover to work with your Maggies and subwoofers.

4. I've tried blending without using an exteranl crossover before, and while you can indeed improve your sound, you won't really get the ultimate performance without an external crossover.

Have fun!

Steven
My guess is that further extention may not be what you're really after -
unless you're a pipe organ guy. If you're down 6db below 33 hz, that's gonna
be inaudible on most recordings. There's a coupla keys on the piano that
MIGHT be slightly diminished, but they're not struck often.

However, that "little dip" in the 50-60hz range is right at the
point where the impact of a kick drum is established. You can certainly place
subs or EQ subs independently of your mains to get more energy in this range
- but you'd need to actively cross from your Maggies at a frequency north of
there, maybe 65-90 hz. A Velodyne SMS-1 sub-controller or SVS
"Audyssey box" (plus an active crossover like the NHT x-2) will
allow for EQing the problem.

The JLs (12" or higher) definitely show more beep bass extention than
the MJs or (almost any of)the RELs on tests. They are also show
"tight/fast" respone (group delay), but not quite as well as MJ or
REL and they are expensive. I chose Rythmik Audio 12" subs which look
like REL/MJ in terms of group delay, but offer better extention.

These observations are based on test results at AVTalk.com (seems to be dark
now) and HTShack.com - not on listening experience, so take that FWIW.

Good Luck,

Marty
I own a version of these with my hybrid stats. They do as advertised. They were specifically designed with Magneplanars in mind. Give Duke a call or email at audiokinesis.com. He'll give you more facts. Also, a friend of mine has the full tilt Planetarium system (bipolar). Pretty awesome.

"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."