Martin Logan Panel tear down !

[C.A.P]

I thought some of you may have wanted to see whats inside these speakers we so desire. I will be using these old Quest panels for project to be announced. I took a few pictures of each stage on the tear down. I know its gory but it had to be done (They were after all done , So I'm recycling them for another use). Look at the way the panel is made. The Quest panels are not bonded together at the sides at all. Just the tops. The Mylar is wrapped around the back stator over the 3m tape. as with the spars that were NOTHING but mere weatherstrip. 1/4 x1/16. The Mylar was very durable stuff. Some of you have been wondering about the puncture test. I did that and it takes a fairly sharp object to pierce through it.

One amazing feat is the heat resistance of the stuff. Look at the pic of me holding a 1800watt commercial hair dryer 1 inch away from my leg on HOT high I felt almost NO heat. This stuff has great heat dissipation.

What this tells me is 2 things from what I have seen in the panels.

1 They can stretch and get wrinkled.(humidity, age, shipping damage)
2 The spars loose their adhesion a tiny bit now and then. (age and humidity)

This has been the norm with most panels. The CLS is known to have a buzz every now and then. I have proved the hair dryer works and stops it. What I can conclude is the Mylar has stretched ever so slightly and the adhesive let loose a bit. (on CLS its usually the bottom corners or top corners along the edge of the bass sections) With heat both are corrected at the same time. The Mylar shrinks ever so slightly and the adhesive is heat activated and gets sticky again. This I proved with the one picture of me with the hair drier. I actually stretched the Mylar a bit and heated both the spar and the Mylar and had positive results . Will this take care of all issues. NO but I have used this several times. Both on my CLS and Quests, and other peoples with great success.

You can tell this panel is shot as its covered in heavy dust with dark color to it, When held up to a light you had several dark dots that were from humidity or maybe smoke . Look closely and you can see my initials wiped into one !

 

[C.A.P]

A few more. Look at the material for the Spars. Man they sure have came along way with the clear spars. Finely your Martin Logan panels all in one hand !

 

[nsgarch]

I liked that last pic a lot! I wanted to mention that a certain run of CLS panels (the later version with bass sections each side) had a buzz problem caused by damping patches that came loose (due to some bad adhesive) and fell to the bottom of the panel (between the diaphragm and the rear stator.) I'm not sure, but I think these damping patches (three per bass section) were only used on the CLS panels. They are also made of mylar and are sort of parallelogram shaped /_/ and very hard to see if the light isn't just right. There's no fix, the panel has to be replaced.

 

[User211]

Heat resistance? Take a lighter to it Does it burn/melt?

I would have thought the true reason you won't feel much heat is that air is a good insulator, even 1 inch of the stuff (think double glazing), and the hair dryer output is deflected away from your leg by the film. Try it with aluminium foil / cling film / newspaper and I expect you'd get pretty much the same result - I could be wrong, though.

Anyway, cool destructive shots:eek1: I wouldn't let you close to my system after a few beers!

 

[C.A.P]

Heat resistance? Take a lighter to it Does it burn/melt?

I would have thought the true reason you won't feel much heat is that air is a good insulator, even 1 inch of the stuff (think double glazing), and the hair dryer output is deflected away from your leg by the film. Try it with aluminium foil / cling film / newspaper and I expect you'd get pretty much the same result - I could be wrong, though.

Anyway, cool destructive shots:eek1: I wouldn't let you close to my system after a few beers!

Ask and you shall receive!

I agree with the air space as a insulator. This is just a quick guesstimate or Polish science fair on what this stuff is capable of.

1. Flame melts Mylar fairly Quickly. but its not a sudden wrinkle up mess. This stuff is tough for its weight !

2 The Foil heated faster and and damn near burnt my leg !

3 Paper heated as fast as 30 seconds and I could feel the burn starting.

The Mylar has a firm unwrinkled feel. It is not a sticky grippy feel like Saran Wrap. Remember I could hold the hair dryer on high as long as I wanted with no real heat transfer or pain. I have heard of people melting Mylar with HEAT guns.

 

[User211]

Well, there you go - you never know til you try! This is school kid physics I guess, but tis all good fun.

 

[pidigi]

great job!

Hi Chris,

very interesting and instructive!!!! I think I'll do the same with my old panels!

The Quest panels are not bonded together at the sides at all. Just the tops.

Really???? Ok, from one point of view this makes sense: if you stretch the mylar horizontally than it will be closer to the inner stator respect to the outer one, reducing the escursion and increasing distorion. But anyhow I supposed that they stretch the mylar mechanically and then attach it to the stators, already stretched in the right sense. Or do you think that the stretching is done by heat shrinking the mylar?

The Mylar is wrapped around the back stator over the 3m tape. as with the spars that were NOTHING but mere weatherstrip. 1/4 x1/16.

Sorry, Chris, I'm trying to guess what a "weatherstrip" is: no useful translation on my dictionary!

Ciao

Paolo

 

[JonFo]

Chris, great write up and pics!

I didn't have the patience (or clean enough hands) to take pics during my tear downs.

But my findings mirror yours with the following variances:

the Monolith panels were likewise pretty easy to open on the sides, but were still pretty well 'stuck' together.
The tops and bottoms were the hardest to unglue on the large Monoliths.

The SL3 panels were much more symmetrical in terms of bonding all around. Not quite as difficult to pry open as the tops of the Monoliths, but still firmer than one would think.

While the Mylar is indeed pretty strong (and therefore the 'Shower" cleaning method is pretty safe), I did find that the old SL3 (which I bought used and abused) diaphragm had tons of dust and smoke particles on it.

Which leads to the constant drumbeat for vacuuming the panels (on both sides), even if they look OK.

 

[pidigi]

Which leads to the constant drumbeat for vacuuming the panels (on both sides), even if they look OK.

.......not easy on Monoliths I-II, th rear grill cover is fixed..... but then no dust should be present, I hope....

Ciao

Paolo

 

[C.A.P]

Hi Chris,

very interesting and instructive!!!! I think I'll do the same with my old panels!



Really???? Ok, from one point of view this makes sense: if you stretch the mylar horizontally than it will be closer to the inner stator respect to the outer one, reducing the escursion and increasing distorion. But anyhow I supposed that they stretch the mylar mechanically and then attach it to the stators, already stretched in the right sense. Or do you think that the stretching is done by heat shrinking the mylar?





Sorry, Chris, I'm trying to guess what a "weatherstrip" is: no useful translation on my dictionary!

Ciao

Paolo

Weatherstripping is usually Foam or Neoprene material that comes in many widths or thickness. It has a sticky back to adhere to the contact surface. the other side has a soft feel that can be compressed a bit to seal out air.

The heat shrinking of the Mylar is accomplished by doing the whole area. Its a complete shrink as to say. Not just a tiny spot. If I see wrinkles I start out 6 to 7 inches away and work my way down very slowly to it them past it 6 to 7 inches. I think a good commercial hair dryer works best as it has the safest results. I have tried to burn the Mlar with the 1800 watt one I use and its damn near impossible. Now that being said to distort the Mylar ever so slightly in one spot can wreck havoc too. That is why I suggest you start out large and disperse the heat accordingly.


JonFo Showering I think is a LAST ATTEMPT! It not only removes the loose dust but some of the actual coating too. Also the soap or water itself gets to the adhesive potentially breaking it down. Some have had success bringing their panels back this way. But I wonder how long it lasted before they had to get new ones? Some of what you see as gray is the coating ML deposits for conductivity. Its what hold the contaminants ! That is why I recommend it as a LAST resort. I tried with a pair of Quests with no positive results. When the dust gets burnt in and they are gray its over . Sit down have a cigar and a glass of wine and celebrate the times well spent and the $800 or so you just spent on renewing your outstanding 20 year old speaker that will destroy most designs today !

 

[VanDaRo]

Good stuff, CAP. But I would like to add two things:
1) Drinking and listening to tunes is a good and recommended thing !!
2) Smoking inside the house is not recommended, even if your panels are completely roached !!

:music:

~VDR

 

[pidigi]

Weatherstripping is usually Foam or Neoprene material that comes in many widths or thickness. It has a sticky back to adhere to the contact surface. the other side has a soft feel that can be compressed a bit to seal out air.

Thanks Chris. I suppose that this weatherstrips have the adhesive side toward the stators, while the non-adhesive side is in contact with the mylar. Am I wrong?

My old Monolith's panels have, instead of weatherstrips, a double coated tape. No brand name on them, could be 3M but I don't know if, at the time the panels have been built, the VHB was already on the market.
It is white, or better it WAS white, now is almost yellow..... not black as the new panels, though.
I don't know if they removed the paper coating on the side that is in contact with the mylar, I'll know about that when I'll do your postmortem examination on my panels too.

Ciao,

Paolo