ESL 57 : how much weight on the jig ? - diyAudio
Go Back   Home > Forums > Loudspeakers > Planars & Exotics

Planars & Exotics ESL's, planars, and alternative technologies

Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Reply
 
Thread Tools Search this Thread
Old 4th April 2010, 08:30 PM   #1
diyAudio Member
 
Join Date: Feb 2004
Location: Caen - France
Default ESL 57 : how much weight on the jig ?

The ultimate secret in the universe after women : how much weight to put on a jig, more or less the same as the one used by factory ?

It seems to me that no-one really knows, that professional re-furbisher made their own minds themselves, that DIYers do it the way they feel it (and at the end this is not worse than old panels they had).
Of course I read some figures here and there. Most reliable ones seem to be 45 for treble and 60 for bass (applied to 40*80cm). But I can't believe this is kg. Pounds seem much more acceptable. But maybe I am wrong.

So, anyone has the answer to the second most protected secret in the universe ?
__________________
Quad fan ! One hobby: re-build ESL 57
  Reply With Quote
Old 7th April 2010, 09:56 PM   #2
diyAudio Member
 
Join Date: Feb 2004
Location: Caen - France
Is there any info on this jig in the book "QUAD - The Closest Approach" (page 45) ?
Thank you !
__________________
Quad fan ! One hobby: re-build ESL 57
  Reply With Quote
Old 8th April 2010, 11:04 AM   #3
diyAudio Member
 
Join Date: May 2006
Location: Netherlands
However nice it is, there are no technical production details in that book that I can recall.
  Reply With Quote
Old 8th April 2010, 11:39 AM   #4
diyAudio Member
 
Join Date: Feb 2004
Location: Caen - France
Quote:
Originally Posted by arend-jan View Post
However nice it is, there are no technical production details in that book that I can recall.
Thanks for this reply.
Meanwhile I found some similar conclusion here: Planar Speaker Asylum: The book... by Gary Jacobson
Yet there are some pictures of the jig in this book but maybe nothing more than these ones:
One Thing Audio/Manufacturers/Quad/Pictures

I am interested in photos because this could give information on the weights to apply. Certainly not directly the value itself but at least the relative values between a bass and a treble panel.
For example, on the 3rd photo, we can see the weights used for tensioning the bass panel. For me there is no way that it makes 60kg.
On the same photo or on the first one, in background, we see a similar jig but with (much ?) heavier weights: is it for treble panel ?

My intention is not to set up an international business. I just want to repair my ESL. My jig is ready, mylar was just received,... just have to find the right tension to apply now.
__________________
Quad fan ! One hobby: re-build ESL 57
  Reply With Quote
Old 14th April 2010, 07:55 AM   #5
diyAudio Member
 
kavermei's Avatar
 
Join Date: Jan 2005
Location: Lokeren, Belgium
Send a message via MSN to kavermei
Fabien,

"60" could be pounds or kilos, remember the mylar film has very high elastic modulus and can take a lot of tension with a minimum of strain.

I used to stretch my film by hand, using plastic tape, and I remember I had to apply a lot of force to get it nicely stretched taut.

if you don't find the exact values, you can increase the weights until the membrane has the desired resonant frequency. This can be tested by tapping it. The problem with this is that, if you heat-shrink the membrane afterwards, the resonant frequency will go up. So it is hard to estimate the final resonant frequency.

Kenneth, quad fan (but not owner )
__________________
Never send a human to do a machine's job. --Agent Smith
  Reply With Quote
Old 14th April 2010, 12:09 PM   #6
diyAudio Member
 
Join Date: Feb 2004
Location: Caen - France
Quote:
Originally Posted by kavermei View Post
Fabien,

"60" could be pounds or kilos, remember the mylar film has very high elastic modulus and can take a lot of tension with a minimum of strain.

I used to stretch my film by hand, using plastic tape, and I remember I had to apply a lot of force to get it nicely stretched taut.

if you don't find the exact values, you can increase the weights until the membrane has the desired resonant frequency. This can be tested by tapping it. The problem with this is that, if you heat-shrink the membrane afterwards, the resonant frequency will go up. So it is hard to estimate the final resonant frequency.

Kenneth, quad fan (but not owner )
Indeed I think now that the bass panel will not need a lot of weights contrary to the treble panel which will require very high tension.
Measuring the desired resonant frequency is a nice alternative. But what is the resonant frequency to be achieved with each panel ? In which conditions ? Un-bonded, bonded and charged, ...
If measuring is done once bonded then this can mean a lot of trials and a waste of mylar.
I will avoid heat-shrinking because this is not very predictable and repeatable.
__________________
Quad fan ! One hobby: re-build ESL 57
  Reply With Quote
Old 14th April 2010, 12:37 PM   #7
diyAudio Member
 
kavermei's Avatar
 
Join Date: Jan 2005
Location: Lokeren, Belgium
Send a message via MSN to kavermei
If you could stretch the mylar with one stator laying underneath, then I think a pretty good measurement can be made. I don't think gluing and charging will make a big difference. The main parameters will be the tension and the distance between the diaphragm support pieces.

Afterwards you can remove the stator from the work bench and re-tension the film for coating and gluing.

If you are refurbishing several old panels you can adjust by ear, by tapping another old panel's diaphragm for reference. Otherwise it's a little more difficult, maybe use microphone, soundcard and FFT program to measure it?

I don't know what the nominal res. freq. is for the Quads, maybe someone else here will know?

Kenneth
__________________
Never send a human to do a machine's job. --Agent Smith
  Reply With Quote
Old 14th April 2010, 12:57 PM   #8
diyAudio Member
 
Join Date: Feb 2004
Location: Caen - France
Quote:
Originally Posted by kavermei View Post
If you could stretch the mylar with one stator laying underneath, then I think a pretty good measurement can be made. I don't think gluing and charging will make a big difference. The main parameters will be the tension and the distance between the diaphragm support pieces.

Afterwards you can remove the stator from the work bench and re-tension the film for coating and gluing.

If you are refurbishing several old panels you can adjust by ear, by tapping another old panel's diaphragm for reference. Otherwise it's a little more difficult, maybe use microphone, soundcard and FFT program to measure it?

I don't know what the nominal res. freq. is for the Quads, maybe someone else here will know?

Kenneth
All right I will practise.

But knowing the right weights to apply would have been so simple !

Just one point: applying a charge makes a big difference. Because it corresponds to negative compliance (opposite in sign to the one due to mechanical tension) and this reduces significantly the resonance frequencies.
It is so important that a safety factor has to be respected (see papers from Baxandall if I remember well).
__________________
Quad fan ! One hobby: re-build ESL 57
  Reply With Quote
Old 14th April 2010, 01:09 PM   #9
diyAudio Member
 
kavermei's Avatar
 
Join Date: Jan 2005
Location: Lokeren, Belgium
Send a message via MSN to kavermei
Quote:
Originally Posted by Fabien Lefebvre View Post
Just one point: applying a charge makes a big difference. Because it corresponds to negative compliance (opposite in sign to the one due to mechanical tension) and this reduces significantly the resonance frequencies.
It is so important that a safety factor has to be respected (see papers from Baxandall if I remember well).
Hmm, interesting, will check! I have a PDF of his book chapter here.
__________________
Never send a human to do a machine's job. --Agent Smith
  Reply With Quote
Old 14th April 2010, 01:19 PM   #10
orjan is offline orjan  Sweden
diyAudio Member
 
Join Date: Mar 2005
Location: Stockholm
Hi,

From Baxendall's chapter in Loudspeaker and Headfone Handbook, the polarized resonance frequency is for bass panel 70 Hz and treble 260 Hz.

/örjan
  Reply With Quote

Reply


Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Who sells mylar for ESL 57 ? Fabien Lefebvre Planars & Exotics 5 6th March 2010 08:42 PM
Esl 57 Tenson Multi-Way 3 19th March 2008 05:38 PM
ESL 57 Grills are ... ? skip_scratch Planars & Exotics 2 9th January 2008 08:06 PM
Non-oversampling DAC with ESL-57? TimA Digital Source 6 16th August 2006 02:50 PM
Quad ESL-57 (pair) TimA Swap Meet 2 14th November 2005 11:34 AM


New To Site? Need Help?

All times are GMT. The time now is 06:43 PM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright ©1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2