[Davey]

Sorry if I'm apparently out of the loop on this but........this (vague) mod suggestion from Wendell is to take an existing mylar panel and "strip" the existing wires from it and then lay down a new "quasi"-woofer with a reduced pattern thereby decreasing efficiency but increasing "speed?" 

Cheers,

Dave.

[jk@home]

Heh, yeah, I suppose it's a bit scary in that regard. Maybe that's why more people haven't tried it? But from what I've seen, stripping and rewiring the diaphragms isn't actually a biggie, people use Magnepan's home kit to repair delamination on older models and judging by what they say it isn't hard. More of a psychological barrier, perhaps? After all, you could always just put the wire back if you didn't like the results, and it seems to me that stripping and laying new wires has to be easier than building new frames. (Of course, given the state of my shop, getting a walrus to fly would be easier than building new frames . . . )

I do know that Wendell has tried both the frames and the low mass mod and found that the low mass mod has more of a sonic effect. And the quality of the results have been subjected to blind testing. I think he was puzzled that more people didn't do the mod -- I know of only one person who's going ahead with it. I know that I was.

Yeah, I'm a little gun shy on this, since a few years ago I trashed a panel trying to do a straight wire mod (bypassing the terminal strips). My problem is that usually when a manufacturer goes to the trouble of announcing a mod like they did on AA, they usually follow up with either an available mod kit, or at least a detailed parts list and instructions, with the option of a in-factory upgrade. Unless of course they have done this, in which I stand corrected.

http://db.audioasylum.com/mhtml/m.html?forum=mug&n=175229&highlight=Wendell&search_url=%2Fcgi%2Fsearch.mpl%3Fsearchtext%3Drichardson%2B%26b%3DAND%26topic%3D%26topics_only%3DN%26author%3D%26date1%3D%26date2%3D%26slowmessage%3D%26sort%3Dscore%26sortOrder

Anyway, thanks for the Neo-3 PDR idea, that sounds like something doable for me in the future.

[Rclark]

So we're replacing the mylar or the wire?

[josh358]

Sorry if I'm apparently out of the loop on this but........this (vague) mod suggestion from Wendell is to take an existing mylar panel and "strip" the existing wires from it and then lay down a new "quasi"-woofer with a reduced pattern thereby decreasing efficiency but increasing "speed?" 

Cheers,

Dave.

Yep. You're reducing the mass of the panel, which should extend its high frequency response and, if Thiele and Small aren't lying to me, reduce it's "Q" (and raise Fs).

[josh358]

So we're replacing the mylar or the wire?

Just the woofer wire.

[josh358]

Yeah, I'm a little gun shy on this, since a few years ago I trashed a panel trying to do a straight wire mod (bypassing the terminal strips). My problem is that usually when a manufacturer goes to the trouble of announcing a mod like they did on AA, they usually follow up with either an available mod kit, or at least a detailed parts list and instructions, with the option of a in-factory upgrade. Unless of course they have done this, in which I stand corrected.

http://db.audioasylum.com/mhtml/m.html?forum=mug&n=175229&highlight=Wendell&search_url=%2Fcgi%2Fsearch.mpl%3Fsearchtext%3Drichardson%2B%26b%3DAND%26topic%3D%26topics_only%3DN%26author%3D%26date1%3D%26date2%3D%26slowmessage%3D%26sort%3Dscore%26sortOrder

Anyway, thanks for the Neo-3 PDR idea, that sounds like something doable for me in the future.

No kit, but Wendell went to the trouble of making the supplies available. Really, all it needs is some measurements to get the impedance right with a series/parallel arrangement.

[Rclark]

Hmmmm tell you guys what, if you're willing to talk me through this, I'm gonna spend a good five months with my maggies when they eventually come back, and then if you guys help me I'll attempt this mod. Why not.

 I'm sure I can order replacement panels from Maggie if I don't like it. I like taking things as far as they can go.

[jk@home]

No kit, but Wendell went to the trouble of making the supplies available. Really, all it needs is some measurements to get the impedance right with a series/parallel arrangement.

Allrighty then, that sounds promising . Do you have a list of all the parts and material needed to do the mod? Would one order from the parts and service dept, or directly deal with Wendell? And explain the impedance measurement thing, does the crossover need to be modded also (and will a series x-over work with this)?

Damn, I'm pretty sure I threw away my old damaged panels, that would of been nice to experiment/practice on. I did dissect one of them to see how they were constructed, a surprisingly simple design. The magnets were similar to ones one would find in refrigerator gaskets.

Hmmmm tell you guys what, if you're willing to talk me through this, I'm gonna spend a good five months with my maggies when they eventually come back, and then if you guys help me I'll attempt this mod. Why not.

 I'm sure I can order replacement panels from Maggie if I don't like it. I like taking things as far as they can go.

When I bought replacement panels a few years ago, they were $175 each plus shipping.

[Rclark]

 apparently the big crossover upgrade on the magnestand has that square shaped Jupiter Beeswax cap bypassed with Mundorf silver in oils... doesn't say anything about the resisters, inductors, etc, but I we can assume its all of the same level.
 
 Danny Richie uses the same cap now too, the Jupiter in the Super V. So needless to say I'm intrigued. So far I've got nice caps in my amp, I have ClarityCaps in my amplifier and that was a BIG upgrade to the sound.

[jk@home]

I added a Mundolf SIO as a bypass on my copper Obligato caps, added to a nicer high end. If I remember correctly, they have a pretty long break in period.

[Rclark]

Yeah, he's saying about 300 hours. I can deal with that. Says it goes from incredible to spectacular during that time period.

[SteveFord]

Mr. Gunn is not here so no Gunn Bashing, por favor. 

As for this all ribbon design we'll see what transpires. 
Been offline for a bit due to my wonderful Internet Service Provider. 
We can bash them, if anyone cares to!

[josh358]

Allrighty then, that sounds promising . Do you have a list of all the parts and material needed to do the mod? Would one order from the parts and service dept, or directly deal with Wendell? And explain the impedance measurement thing, does the crossover need to be modded also (and will a series x-over work with this)?

Damn, I'm pretty sure I threw away my old damaged panels, that would of been nice to experiment/practice on. I did dissect one of them to see how they were constructed, a surprisingly simple design. The magnets were similar to ones one would find in refrigerator gaskets.

When I bought replacement panels a few years ago, they were $175 each plus shipping.

Where we left it on the planar asylum, JBen was going to measure his MMG's (old type) and I was going to measure my new ones. Which to my embarrassment I still haven't done but I can do that, the socks are off. All we need is the resistivity of the tweeter foil. It's going to be higher than the resistivity of the woofer panel and we need to parallel it so the woofers to get the impedance down to a nominal 4 ohms. Or we could just use the ratio of the number of woofer loops to the number of tweeter loops, since the woofer and tweeter are going to have roughly the same DCR.

Wendell said that there was a significant efficiency drop so I assume it needs to be bi-amped.

I think his preference now is that we find a source of foil ourselves. He says it shouldn't be difficult.

[Davey]

I must be missing something obvious here because the trade offs seems silly to me.  The magnet structure is the same, the mylar is the same and you're going to reduce the motor strength greatly (of an already highly inefficient speaker) in order to achieve some modest increase in "speed" and possibly bandwidth?
Wendell says there's "a significant efficiency drop."  I have no doubt about that! 

I think the objective of an "improved" transducer/motor structure should be to increase motor strength, not decrease it.  Stronger magnets, lighter material than the stock mylar, etc, etc.  Some of the excellent DIY electrostat efforts I've seen look to achieve these goals pretty well.  But, of course, highly limited bass capability.  However, we have some good solutions for that.

Cheers,

Dave.

[SteveFord]

Magnepan has got something cooked up involving the MMGs which they're pretty excited about  - little teaser ad in the current issue of TAS and it will be demoed at the upcoming CES.

[josh358]

I must be missing something obvious here because the trade offs seems silly to me.  The magnet structure is the same, the mylar is the same and you're going to reduce the motor strength greatly (of an already highly inefficient speaker) in order to achieve some modest increase in "speed" and possibly bandwidth?
Wendell says there's "a significant efficiency drop."  I have no doubt about that! 

I think the objective of an "improved" transducer/motor structure should be to increase motor strength, not decrease it.  Stronger magnets, lighter material than the stock mylar, etc, etc.  Some of the excellent DIY electrostat efforts I've seen look to achieve these goals pretty well.  But, of course, highly limited bass capability.  However, we have some good solutions for that.

Cheers,

Dave.

According to Wendell, the benefit is from greater speed. He said it's preferred in blind testing. I assume this is because it's a midwoofer, with a single pole crossover, so it's playing pretty high up?

The foil also seems to reduce "Mylar noise" resonances, some of the reviews of the .7's comment on this and I've noticed that effect from tapping on the various diaphragm areas of my MMG's -- the foil area seems to have better damping.