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Planar Speaker Asylum

Tri-amping Magnepan 20.1

207.171.180.101

Folks,

I am quite surprised by the lack of information about tri-amping 20.1, given that it would appear that a large portion of the owners opt to bi-amp them. I do realize that tri-amping would require physical and not-easily-reversible modifications of the speakers, but still -- it almost feels as if it has never been done... Please share your experience if you are one of the adventurous ones who have.

This is not a rhetorical question. I am planning to do it, but I am hoping to leverage the collective experience before I put a knife to Maggies (shudder...)

Thanks very much!
sergey

Follow Ups:

RE: Tri-amping Magnepan 20.1 - thebordas 18:51:31 09/25/10 (4)
Multiple amps, wires, PC's and an overly complex active crossover plus possible panel surgery?? I would suggest you care less about fine music reproduction and more about conducting a lab experiment....the "Monster" may live, but it will not be pretty!
dave_b
- RE: Tri-amping Magnepan 20.1 - Satie 04:00:41 09/27/10 (3)
  Seriously?
  
  Triamping any of the maggies is quite easy and straightforward - you order a Marchand with the the recommended and calculated stock values and different output level amps from the same series of a manufacturer's line. The improvements are enormous, the only real problem is going beyond the simple part. But once you do the basic step, you have a multiplicity of options to tune amps and cabling, and the crossover itself.
  - RE: Tri-amping Magnepan 20.1 - thebordas 05:28:26 09/27/10 (2)
    Too many variables and cables for my liking, but best of luck:O)
    dave_b
    - RE: Tri-amping Magnepan 20.1 - Davey 07:47:11 09/27/10 (1)
      I know it seems rather counter-intuitive that a system like this would have less variables than a conventional system, but it's true. Many folks have a hard time wrapping their heads around this concept....so you're not alone.
      
      I think part of the problem is that some folks who have auditioned systems like this were listening to implementations that used active crossovers with generic filter slopes. Those are...generally...not suitable since acoustic responses of the drivers rarely can be optimum unless driven with tailored slopes from dedicated crossovers.
      
      A line-level crossover implementation with power amplifiers driving panels/xducers directly is a 'simpler' system than a typical conventional setup. Ponder that for a bit.
      
      Cheers,
      
      Dave.
      - RE: Tri-amping Magnepan 20.1 - thebords 07:53:57 09/27/10 (0)
        
        In Reply to: RE: Tri-amping Magnepan 20.1 posted by Davey on September 27, 2010 at 07:47:11
        
        Right then, I'll have to kick it around in me noggin a bit....cheerio, pip pip and all that:O)
RE: Tri-amping Magnepan 20.1 - Green Lantern 20:31:57 09/24/10 (0)
sounds like the ultimate adventure but (at least for me anyway) it'd be hard voicing just 'one' amp; let alone 3!
I'd always wondered how they would sound with a moderately powered tube amp on the ribbons, a nicely powered amp on the mids and a brute force amp on the bass panels..wow
The idea sounds intriguing!
"You don't have to be faster than the lion....
just the guy running next to you.." -anonymous

Edits: 09/24/10
RE: Tri-amping Magnepan Tympani IV or IVa not MG20.1 - Satie 20:18:34 09/24/10 (5)
I have done my Tympani IV. I also replaced the midrange, which is the weakest link on the T IV, the shorter length mid does not reach down far enough and leaves the crossover still in the 300+ hz range. Ideally it would go down to just below 200 hz.

I would only triamp an MG20.1 if the 5 foot width of each Tympani were too much for the room. I have a 17X19+ room, and with an 8 foot spacing between the speakers, and toe in that leaves 1 foot from the sidewall on either side. There is no problem with the fit since the room is heavily furnished and the walls covered in bookcases and the key backwave reflection area is treated for absorption.

The main advantage of the 20.1 is the push pull midrange. But it is compromised by being on the same panel as the bass.
For my Tympani I took out the original T IV midrange and replaced it with a line array of 6 Neo 8 drivers on each side (nigh efficiency high output push-pull planar drivers). The results are grand and I dare say the Mg20.1 is not better.

I thought that the Mg20.1 bass would be superior because of the push-pull construction, but it seems they used it to save on magnets rather than obtain higher output power and sensitivity. So the Tympani still wins on bass.

The separate mid/tweeter arrangement is also a substantially better construction and avoids bass induced TIM in the midrange and treble.

I suggest you sell the MG20.1 and get a recently refurbished Tympani IVA and sell off or put away the midrange drivers and replace them with either a line array of 7-8 Neo 8 drivers (sensitivity about 95 db), or with a BG Radia RD 75 (sensitivity about 87 db). The sale of the MG20.1 can probably finance the Tympani purchase and the replacement midrange, and still leave you room to fund Mye stands for all the panels, and perhaps part of the cost of the bass amplifier (you should get 2000 watts per channel into 4 ohms to make sure you have enough power).

In any case, I can help, and I will volunteer Andy too - see how nice I am...
- Replacing the (shorter) T-IV midrange with the Neo 8s makes sense ... - andyr 00:56:23 09/25/10 (4)
  but I wonder if the full-length T-IVa midrange perhaps is a lot better than the IV mid-range?
  
  Comparing bass delivery between a 20.1 and a T-IV/T-IVa would be interesting. The Tymps have 1254 sq in of bass panel compared to only 800 sq in for the 20.1 - so should give "more" (ie. lower) bass ... yet the 20.1 has magnets both side, so should deliver better bass transients?
  
  But, yes, the fact that theere's only the one frame for the 3 drivers in the 20.1 severely compromises the end result.
  
  Regards,
  
  Andy
  - RE: Replacing the (shorter) T-IV midrange with the Neo 8s makes sense ... - Satie 03:25:26 09/25/10 (0)
    The T IVa midrange extends deeper and allows a lower crossover, but it is nearly identical, just slightly lighter wires than the T-IV it has better detail and transient attack, but still much slower than the tweeter, and the discontinuity is still obvious, as you probably noticed.
    
    The Tympani, when braced and powered sufficiently (something that could just barely be done when the model was current). Do go down to 25 hz flat, and provide plenty of output below that - or actually have giant room gain at the bottom octave.
    
    Had Magnepan used the same number of magnets on the Push pull bass then at least dynamic response could have been better, but they didn't so there is no real advantage it turns out, but for the lower cost and easier setup. Another minus is that it is easy to bottom out the woofers - where the tympani at least continue to give a half waveform on the lowest octave at high volume - much better than nothing on the MG20.x.
    
    Its not really that bad to build Tympani these days, it should be possible to do it for less than $20k. The biggest cost increase in the Tympani construct relative to the MG20 comes from the dealer cost to set up at the customer's room. Second is the smaller production runs due to sales limitations from the limited WAF (think size) and greater cost.
  - Triamping 20.1 - triamp 03:19:40 09/25/10 (2)
    I have triamped 3.6's, and there was a user who posted in 2008/2009 whom I knew who had triamped 20.1's - AND a pair of tympany bass panels as a subwoofers AND a pair of velodyne subs below that. He used a pair of DEQX's as crossovers for this 5-way setup. He said it sounded fantastic, and I have no reason to doubt him. I forget his moniker, - was it Helmholz maybe? - but I know for sure he has posted here.
    
    (Was it velodyne subs at the bottom? Maybe it was some other sub, I can't remember. But I think the crossover to the sub was 64 dB/octave at 25 HZ... my memory is a bit fuzzy on the dynamic sub details, but for sure he had triamped 20.1's and 2 tympany bass panels )
    - RE: Triamping 20.1 - Satie 03:49:47 09/25/10 (0)
      I don't remember coming across that one, but there is someone with a 3.6 using Tympani IV bass panels for subwoofers. I had suggested he try a crown 3.6 vz to power them, but he could not deal with the fan noise so he ended up with Classe CAM350. I still feel guilty forgetting to emphasize the fan noise when suggesting it to him.
      
      I don't mind it because I play loud enough so that the fan noise is barely audible on quiet passages - and there is the central air and the dedicated air conditioner for the listening room. Without the air conditioner the room is uninhabitable within a couple of hours, so it just stays on. I turn off the HEPA filter when I am there.
    - RE: Triamping 20.1s??? ... hemholtz has ... - andyr 03:26:19 09/25/10 (0)
      T-IVa bass panels (2 each side) augmenting his 3.5s (I think - not 3.6s). How do I know this? ... bcoz he gave me his T-IVa mid panels & ribbons (which he wasn't using) for my Frankenpans.
      
      Not sure whether he has subs below the T-IVa bass panels but I think so.
      
      Regards,
      
      Andy
I'm not aware of *anyone* who has done this ... - andyr 17:09:24 09/23/10 (2)
probably because those with the money to buy 20s/20.1s typically lack the "DIY" gene! :-))

If I could afford a pair, I certainly would!! It's no different to triamping IIIa/3.6 series ... and there are quite a few of us who have done that.

Good luck,

Andy
- RE: I'm not aware of *anyone* who has done this ... - Webnick 19:02:52 09/23/10 (1)
  Its quite possible that no one has ever posted about actively triamping 20.1s for as you point out, just the 20.1s alone require significant $$$. Add in the substantial amplification requirements and the active XO and cabling, and the cost could be humbling.
  
  On the subject of conversion, however, I think the idea that it is "not-easily-reversible" may not be quite right if the 20.1s use the same push-on connectors that the 3.6Rs use - I actively triamped my 3.6Rs (5 amps!) and it was easily reversible as I didn't solder any connections. But I have no experience with the 20.1 drivers to be sure.
  
  20.1s actively triamped must be close to nirvana! All that really good bass that only that model and the IVas put out all by their lonesome coupled with the shimmering Maggie true ribbon tweeters and sublime midrange - yum! Man, talk about "audio porn".
  
  Illegitimus non carborundum.
  - "The same push-on connectors that the 3.6Rs use"?? ... - andyr 19:59:45 09/23/10 (0)
    You're right mate - it should just be a matter of unplugging the tab connectors, to bypass the internal (mid/ribbon) XO. :-))
    IMO it would indeed transform the 20.1s ... but, yes, at quite a cost! And you'd have to put them into hardwood frames, to get the full benefit! :-))
    But sorry, if the definition of "porn" is something that gets you hot ... triamped 20.1s are not audio porn to me! Enough people have now come round to listen to my triamped "Frankenpans" to confirm my initial impressions! :-))
    IE. that isolating the mid from the bass produces a significant improvement in the sound ... and of the stock Maggies, only the T-IVa does this (well, the T-IV does as well but appears to have a much smaller mid-range panel, which I think would have to be inferior - so I left it out!). I think the 20s & 20.1s have the mylar separate (in the sense that the clamp between mid & bass which on yours only goes down 1/2 way, goes all the way down on the 20s/20.1s) but the drivers are still all held by the one frame. Whereas the T-IVa has a separate frame holding the mid panel and the ribbon cage.
    However, if the 20.2s came out with 2 frames per side - that would be audio porn!! :-)) Why doesn't Magnepan do this?
    Regards,
    Andy
    
    Edits: 09/23/10

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