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-   -   Magnepan/ESL combo (http://www.diyaudio.com/forums/planars-exotics/178853-magnepan-esl-combo.html)

SM7UYJ 10th December 2010 09:58 AM

Magnepan/ESL combo
 
Hi,

I'm planing a new winter project and would like your input!

I receantly got hold off two pairs off old Magnepan MG2 who need to be rebuilt as the coils have become lose from the membrane.
The plan is to rebuild one pair and use this as a pure basspanel in combo with a electrostatic mid/high-panel.

Now to my questions:

How would you build the mid/high section?
I have tools to cut sheet metal but max 10000mm long => one 1m section or two 7-800mm, but at what width?

Should I have the Magnepans and the stats in separate frames or build a combined one?

/R

SM7UYJ 13th December 2010 09:57 AM

No one :confused:

XO will be 100-200Hz.

/R

DaveG 13th December 2010 12:42 PM

Having MG1-A improved (similar to the MG 2 I believe) and also Acoustat 1+1's, I’ll make some comments on this.
First - I believe the full range Acoustat’s at 9” x 94” panel area have better bass than the 1A’s. Neither are perfect.
1A’s may have more apparent dynamic sound and maybe sound more like a very, very clean cone woofers than the electrostats, but the Acoustat’s are somehow more open and detailed.

The “sound” of the two panel type is different. I’m not sure they will smoothly blend together. These comments are based on my using the exact same CD player and amps. The two speakers present different/difficult loads and neither of my amps, one tube, one SS, is well suited for either of these speakers, and that may have contributed to the different flavor of sound. That is why I now use direct drive amps for the Acoustats.

To me, although the Acoustat bass is far from perfect, the seamless crossoverless quality of the lower mid/mid bass/upper bass region is a great benefit.

I once started panels using the Sanders method of sheet metal and plexi glass and never completed the project. On the long project list is to try building improved Acoustat style panels, using the light louver/wire method and I would use the wire spacing and stator/mylar dimensions and mylar gauge information from a great thread here on DIY about building Acoustat style panels.

Myself, I would build Acoustat style panels, tall and skinny, and maybe try your MG 2’s as woofers/subwoofers at a lower frequency, 100 hz or 70 hz. If you incorporate the MG 2 panels into the electrostat frames you will not have any other options to reconfigure. (well, maybe you could fill the space with more electrostatic element if you did not like it)
Keeping the 2 speaker panels separate also has it’s problems. I once set up Acoustat Model 3’s (25” x 42” panel size) as subwoofers to the Model 1+1’s. The bass was better but because of different signal path lengths it created an slight artificial reverb effect. The large Model 3’s panels could not be placed close to the main full range panels without fouling up the imaging. A future project (another on the long list) is to build a crossover with some phase/delay adjustment.

Dave

SM7UYJ 14th December 2010 08:35 AM

Hi Dave,

Thanks for your reply!
I have a friend who has a pair off rebuilt MG2's that play well in the lower region but to my liking, lacks in the highs.
In my DIY ESLs its just the highs that I find the best, so I taught I'll combine the two for a complete plannar setup (my ESLs are hybrids with a 12" woofer). The plan is to use active filters and separate amps to make integration "easier"!
Have you measured your Acustats? It would be interesting to know how low they play in room conditions!

/R

DaveG 14th December 2010 11:33 AM

Hello /R,

No, never measured, but Acoustat’s go quite low, 35-40 hz. As a reference point, the “heartbeat” on Dark Side of the Moon is very nice. Not as solid as 10 inch woofers in full transmission lines, but there is a solid feeling of the heartbeat.

I have heard better bass. But the seamless blend is always a problem for me, and for now, I have compromised on the low bass quality in exchange for the seamless blend to the mid bass/ upper bass/low midrange. And yes-I agree that the mid/highs of the electrostatics is great.

You got me thinking about the Magnaplanars today. I have never heard them with a really good high current amp. The slightly more dynamic quality they have, more impact, may be just what is needed for a good low end. You may be onto a good combination.

What do you do now for EQ and crossover point to the woofer? How low do do your panels go?

I have a Panasonic mic capsule and DB meter and signal generator. All manual, no software. Can I perform a near field measurement, just like a standard woofer, with an open electrostat?

Dave

SM7UYJ 14th December 2010 12:57 PM

Dave,

Right now I'm using a passive 12dB XO at 200Hz in the speakers, and dipole compensate up to 100Hz with a active filter in my preamp.

My ESL-panels f0 is abt 50Hz:

http://hem.bredband.net/rcdesign/ESLny5.jpg

(Measured with Tombstone and a DIY-mic and DIY mic-amp)

Measurement off flat ESL panels is not the easiest, specially in the higher regions, but it shows you if your in the ball park or not! ;)

My aim is to cross over as low as possible, but due to space considerations in my listening room, I think a 200mm wide ESL-panels is the limit my better half will accept!

With a 2mm d/s perhaps 200Hz XO is a bit optimistic?

/Roger

DaveG 15th December 2010 07:42 PM

Plot looks good. How wide and tall are the panels that you used for the measurement plot?

I can’t comment on the d/s spacing. Others here with a lot more building experience for that.
Are you crossing over at 200 hz to keep away from the panel resonance?
200mm width should image good. That is a bit narrower than I listen to now. How tall can you go?

But to get back to your original question of separate or combined frames - I myself like the idea of separate frames, like the old sub/satelite idea. Narrow panels image the best. Wide panels have best bass. How can one frame meet both requirements? Maybe a large tall triangle like Apogee ribbons? Maybe the Magnaplanar panels can go under the electrostats? But making it look nice may be a challenge.

I guess a lot is going to also depend on your room requirements.

Dave

NewVista 17th December 2010 06:14 AM

3 Attachment(s)
I will be trying this very thing shortly: ESL surround w/ Mag MG-1 bass panels running in infinite baffle (just found a pair of MG-1 with open circuit tweeter wires - made from fragile aluminum wire, these are often found open). But I don't care, just want 'em for the bass.
Current system has inf baffle Altec 416 horn.

SM7UYJ 20th December 2010 01:02 PM

I finaly got my pair off MG-IIs!

http://hem.bredband.net/rcdesign/MG2aB1.jpg

Two off the panels can be saved by rewiering the tweeter section.

http://hem.bredband.net/rcdesign/MG2aB3.jpg

And two will need to be redone compleatly with new Mylar and wire.

(one panel toataly stripped)

http://hem.bredband.net/rcdesign/MG2aB2.jpg

I have 3m, 4.8m and 12m Mylar at home. Fist taught was to use the 4.8m one, but now thinking if it's not good enough with the 12m one?

The wire and glue weigh alot compared to the film, and the 12m film should be easier to work with in this case.

/Roger

SM7UYJ 22nd December 2010 06:15 AM

I stripped the tweeter section again last night...

http://hem.bredband.net/rcdesign/MG2aB4.jpg

....and rewired using 0.2mm wire.

http://hem.bredband.net/rcdesign/MG2aB5.jpg

The resistance now went down to 6.4 Ohm -alot better!

I'll try to sweep the panels in the next few days to see how well they preform!

/R


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