Quad ESL63 Holes for screws in mebrame make sound ?

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Hi im on my way refitting all menbrames. workes great untill now.

I ran in the folowing issue. when bass is played i get light sound of stuf vibrating, i could jnot find the problem but i think its the holes i made in the menbrane for the screws that go trough the panel.

i used an iron to make these howles with a template , but i can hear some tiny left overs of the foil resonating. any ideas ? to clean that up ???

what method you guys used ?



This is what Hey you says about it

The holes are just large enough to ensure that the bolts and the panel protrusions do not impede diaphragm movement. At high volumes, air resists being moved by the diaphragm, and tries to escape through these spacer holes. This makes no sound when the diaphragm is made of three micron mylar. However, if an ESL-63 diaphragm is made out of thicker material (for instance the 12 micron mylar used in ESL-57 treble panels, or the Saran used in ESL-57 bass panels), you will hear unpleasant candy wrapper or bodily function noises as the force of the air squeezing through the holes causes the diaphragm in the area of the holes to vibrate loudly.


hmmm damned.... back to try 3 mincron to se ih hes right about that :)
 
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the sound i hear is not the cracking they are fresh panels, its like candy wrap resonance only at higher volume with say around 55 hertz. my guess is that the tiny leftovers from making the hole with a solder iron for the 3 support screws in the middle, touching or vibrating at higher spl. mostly around the resonant frequency since it has the highes excursion there. the hole looks prety clean but the original 3 micron holes look cleaner. i tried with a heat gun to clean it up a little. FAIL, should have know to screw up the mechanical tension i aplied. when heating up in the middle the menbrame relaxes.. now my resonance frequency got down from 55 to 30. way to low, also excursion at 30 is even higher. so that panel is a bust. have to redo that one.... its funny and frustrating rebuilding panels im not familiar with, but in the end i will get it right.

someone uses other method then solder iron ?
 
i might try the screw, or maybe even a smaller tip then i use now ? , i can imagine 3um mylar leaves less molten mylar at the edges. someone mentioned the tiny hairs as well when using the solder iron, there are miniscule hairs you stretch when pulling the iron back. i must take a look with magnifing glass if i can find one :) beacuause i did see some bigger ones every now and then and tried to remove them.
 
you have protected the holes when you sprayed the Licron?

This is an important point.
You don't want the edges of the holes driven by the electrostatic forces.
Note that Quad left a wide margin around the holes.
 

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This is an important point.
You don't want the edges of the holes driven by the electrostatic forces.
Note that Quad left a wide margin around the holes.

yep i aplied licron , then after i cleaned a circle, because i could not find any round stickers :) i know licron is removed easy with alcohol, im pretty sure it wont condyct there, i think it where the rugged etches of my hole tiny it may look its prety anoying soundwise. i refoiled all but one of my panels with 3 Um hopefully i can do a comparison test soon, between 6 and 3 Um then we cleared that question once and for all :)
 
How to know how much heat to use, how much heat is too much, and how to judge the effect of heat on the tension of the diaphragm?

Ben

At a temperature of about 150-160 centigrade Mylar would start to relax, assuming it was mechanically pre-stressed. Typically even low mechanical tension like 0.5% is somewhat higher than simply heat-shrunk, or annealed after membrane being glued.
 
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the topic was purely about the holes in the mylar that made noise, in the end it was some hair thin melten mylar. i use solder iron on highest setting to make the holes with the help of a metal thin template.

later i discovered that some leakage noise whas from a bit of old glue that landed on one of the spacers, so the alumnium strip did not contact the mylar all over. this made verry smal hissing noises (when listen to it closely) they are all solved. they are dead silent now when i put them on. sometimes i leave them on for a week and they sound exactly the same as if i turned them on 1 min before use.


Some last thing thats can cause noises on these panels is , not perfectly adherid glue on the inside edge of the frames. this makes a tiny bit of resonance sound possible when playing sine waves on higher volume. i used polyurethane glue just like most repairs use for quad. but im still wondering if a more tacky glue would not work better.

some people uses VHB tapes anyone know one that does not have creep? it should not be of foam type ofcource since it has to be as thin as possible. i like to work with tapes rather then glue but only if it holds just as well. But it gives a bit more damping on the edge of the spacer compared to hard glue like PU to counter these resonances. i think capacity or calving used VHB as spacers, i might ask them to :) maybe there is a verry thin version of it as well. although beit verry expensive :( for a piece of tape
 
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the topic was purely about the holes in the mylar that made noise, in the end it was some hair thin melten mylar. i use solder iron on highest setting to make the holes with the help of a metal thin template.

later i discovered that some leakage noise whas from a bit of old glue that landed on one of the spacers, so the alumnium strip did not contact the mylar all over. this made verry smal hissing noises (when listen to it closely) they are all solved. they are dead silent now when i put them on. sometimes i leave them on for a week and they sound exactly the same as if i turned them on 1 min before use.


Some last thing thats can cause noises on these panels is , not perfectly adherid glue on the inside edge of the frames. this makes a tiny bit of resonance sound possible when playing sine waves on higher volume. i used polyurethane glue just like most repairs use for quad. but im still wondering if a more tacky glue would not work better.

some people uses VHB tapes anyone know one that does not have creep? it should not be of foam type ofcource since it has to be as thin as possible. i like to work with tapes rather then glue but only if it holds just as well. But it gives a bit more damping on the edge of the spacer compared to hard glue like PU to counter these resonances. i think capacity or calving used VHB as spacers, i might ask them to :) maybe there is a verry thin version of it as well. although beit verry expensive :( for a piece of tape

Hi,

The bonding between mylar and spacers must be PERFECT. That is, any gaps will produce buzzing noises. Perhaps, slow-curing and low viscosity epoxies are among the best in gap filling properties, given appropriate application techniques. However the boundary between the spacer and mylar is typically quite sharp, but this kind of glue has a very low creep factor.
About VHB tape I'm not sure. I have heard that ML's switched from VHB to solid spacers and vacuum processing at one point, perhaps to creep, but I'm not sure about this. What I'm sure about is that any sticking surface that remains plastic over long periods of time will creep, despite if it looks like the bond is very good initially.

Regards,
Lukas.
 
Hi,

The bonding between mylar and spacers must be PERFECT. That is, any gaps will produce buzzing noises. Perhaps, slow-curing and low viscosity epoxies are among the best in gap filling properties, given appropriate application techniques. However the boundary between the spacer and mylar is typically quite sharp, but this kind of glue has a very low creep factor.
About VHB tape I'm not sure. I have heard that ML's switched from VHB to solid spacers and vacuum processing at one point, perhaps to creep, but I'm not sure about this. What I'm sure about is that any sticking surface that remains plastic over long periods of time will creep, despite if it looks like the bond is very good initially.

Regards,
Lukas.


yeah i was afraid this was the answer :)

I really like the speed of tape, tack it and done!, the slow cure PU are really slowing my production. i used several diluted PU's and geting a perfect nice coating is hard, if you use more the coating will be perfect but it may squeeze out leading to ugly pieces of glue on the mylar.

Epoxy would work great to, i used it on allot of small pannels, but with the quads im afraid when things have to be redone your stuck with the glue. it is allot harder to remove then PU, and i dont want to screwup quad panels :)
 
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