Others experience re: subs and Magmepan 20


I have a pair of Magnepan 20r’s. Have enjoyed them for years. In my room they go to about 30Hz, response way down at 25Hz.

I am experimenting with a pair of Janis subs. This gets the response to about 25 Hz then down a lot at at 20Hz. It adds a little something but not I am not bowled. over. I hear and feel a bit (in my chest) on some music.

I would like to hear about others have experience with adding subs to nearly full range speakers?

Did you feel you got your money’s worth for "a few silly Hz"?

Thanks
imdoc
a Moog might go a lot lower than 20 Hz on rock tracks

otherwise, sub 30 Hz sounds are pretty much limited to organ music and cannons (Tch. overture)

I’d bet some DSP testing and room treatments would be much more rewarding, tho maybe an amp that really put out a lot of current into 4 ohms(?? dunno what you have now)

Wendell can give you the factory talk on why to avoid cone based subs and to use a pair of DWMs instead

OTOH, many people are happy with (at least the expensive) subs added to the smaller panels
imdoc,

    Forgot to answer one of your questions:
Whether I thought the $3,000 cost of the  DEBRA was worth the cost?

     Unequivocally, yes.  I honestly can't count the number of times I've been listening to music and the music calls for deeper bass (acoustic, percussion or electronic) and the DBA system just powerfully, naturally and seemingly effortlessly reproduces the lowest octaves and blends so seamlessly with the Magnepans reproducing everything else that the result is a sound stage illusion that  just sounds like a beautifully synchronized realistic whole; like the actual musicians are playing in my living room or as if I've been transported to the venue, depending on the recording.
  Logically I know it's a sound stage illusion but it's uncanny how I perceive the bass, even though it is monaural, as emanating from the proper instruments within this illusionary and 3D sound stage.  It's really quite impressive and enjoyable.  .
   I think paying attention to details and being precise in setting up a DBA is critical to getting good results; things like following the progressive locating procedure for properly positioning each of the 4 subs in the room, using trial and error to set the crossover at the correct hz (I found 40hz worked best in my system),  determining the correct relative volume of the DBAS (in relation to your main speakers) by precise setting of the supplied sub amp's rotary volume control knob (mine is set between the 9 and 10 o'clock position) and whether to run your main speakers full range or use a filter to limit their lower frequency duties (Mine run full range without restriction).

    Fortunately, this rather elaborate setup process only needs to be done well once.  You're able to just enjoy your music with consistently stellar performance until you decide to move or upgrade your main speakers. 

     Lastly, I wanted to mention that you can also construct your own custom DBA by using 4 subs of your own choosing.  However, this is likely to be significantly more expensive than a DEBRA or SWARM complete system with the 'law of diminishing returns' also needing to be considered.

Thanks,
 Tim   
I currently have Magnepan 20.7's paired with a single REL G-1 sub-bass driven by ARC 250SE mono-amps. I have found the sub provides an additional fullness and body to music which has been linearly recorded and accurately transcribed to less than 30hz (CD or LP). The improvement in overall presentation is also dependent upon the room size, and in my case, I listen in a 15ft wide by 22ft long room. I would note that I previously had Magnepan 20.0s, and the improvement with a sub was somewhat greater due to its more limited low end.  Due to the inefficiency of Magnepans, ample dynamic power is essential and probably more important than the addition of a sub.     
I have a pair of Magnepan MGIIIa s and now that I have a preamp with dedicated subwoofer ouputs with adjustable crossover points, I was thinking of adding an REL or a Magnepan DWM to the system.  I am thinking more like an 8" sub, since I want a faster response than I think the larger subs will provide (do not really need super powerful bass) and my listening room is not large.

Jim, Rythmik Audio has two sealed subs featuring dual 8" woofers, the F8 and FM8. The only difference between them is the FM was designed to be used as a mid-bass woofer, it’s x/o to a lower-frequency sub being 4th order at 50Hz. Both operate up to 250Hz, and both incorporate the Rythmik Direct Servo-Feedback amplifier.

Also, co-designed by Rythmiks Brian Ding and Danny Richie of GR Research is the unique OB/Dipole Sub, available with dual 8" woofers, though dual 12’s is the more common choice. This OB/Dipole Sub is the ultimate sub for use with all planar speakers, for obvious reasons.

By the way, both Brian and Danny are adamant that because of the design of the 8" and 12" woofers (designed in house specifically for open baffle implementation, and custom manufactured by TC Sounds for Rythmik and GR exclusively), and how they are controlled by the Rythmik Servo-Feedback circuit, the 12" is just as "fast" as the 8", but capable of considerably more output. The sense of "speed" in a woofer is in how quickly it returns to "rest" after the signal has stopped, not how quickly it starts (Rythmik/GR subs have been described as "stopping on a dime"). Subwoofer frequencies are relatively "slow", but woofers, once set in motion, tend to stay in motion. That’s where the Rythmik Servo-Feedback circuit comes into play. If you’ve ever heard the Infinity IRS loudspeakers, you know what I’m talking about. I formerly owned the mini-IRS, the RS-1b (featuring six 8" servo-feedback controlled woofers per side), and the pair of Rythmik Audio/Gr Research subs I now own are considerably better. Leaner, cleaner, no boom, no bloat. It’s the only Open Baffle/Dipole Servo-Feedback Sub in the world! Seriously, if you don’t have room for a pair of Magneplanar Tympani T-IV bass panels (great as subs for Maggie MG series speakers), this is the sub to own.