final 0.3 er audio repair kit - Page 3 - 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 3rd July 2008, 11:40 AM   #21
Calvin is offline Calvin  Germany
diyAudio Member
 
Calvin's Avatar
 
Join Date: Nov 2004
Location: close to Basel
Hi,

the problem with untempered membranes are:
- consistency of parameters within a series
- working points are initially way off and need a settling time of many hours (never asked why a ML sounds so thin and bad when it comes right off of the shipping cartonage?)
- tension/stress within the membrane area is not consistent
- it sounds worse

Designing a flat stator I wouldn´t recommend to solely use mechanical tensioning any more. With the above described method and following the 1:70-1:100-rule and using the typically recommended films of 4mm-6µm thickness the Fs should be >100Hz when tensioning mechanically >1% and heat treating.
Only mechanical tensioning is necessary though with typical films and curved stators. To allow for heat treatment of curved membranes You have to take a different way (that´s one of the mysterious specialties of my new curved stators )

jauu
Calvin
  Reply With Quote
Old 3rd July 2008, 12:04 PM   #22
Bazukaz is offline Bazukaz  Lithuania
diyAudio Member
 
Bazukaz's Avatar
 
Join Date: Nov 2005
Location: Vilnius
Send a message via Skype™ to Bazukaz
Hello Calvin,

I remember reading somewhere that heat shrunk membranes lose some strength and long - term dimension stability. Not sure if this is correct. Maybe it is better to apply more uniform mechanical force. Do ESL manufacturers use heat shrinking method ?

Regards,
Lukas.
  Reply With Quote
Old 3rd July 2008, 07:37 PM   #23
Calvin is offline Calvin  Germany
diyAudio Member
 
Calvin's Avatar
 
Join Date: Nov 2004
Location: close to Basel
Hi,

if You use proper film material the loss of tension should be no problem for years.
ESL manufacturers use thermal treatmet of the film....at least the good ones

jauu
Calvin
  Reply With Quote
Old 4th July 2008, 09:21 AM   #24
diyAudio Member
 
Join Date: Apr 2005
Location: Utrecht
Calvin, could you tell us which manufacturers use heat shrinking?
As far as I know, and based on my own experience, the tension achieved with heat shrinking is quite limited so I doubt if this is the one and only perfect method.
__________________
drs M.J. Dijkstra
  Reply With Quote
Old 4th July 2008, 11:36 AM   #25
diyAudio Member
 
Join Date: May 2006
Location: Netherlands
Hi MJ

The one company that I am 100% sure of to do heat treatment is Quad, both on the ESL as the ESL63. But they don't do it like that.

The crucial difference being that the heat treatment is performed with an oven while the diaphragm tension is being held constant (so it is free to change it's dimensions). This is also the way I do it for my Quad panels.

I suspect that the way Calvin describes it, the final tension will be mostly determined by the properties of the film, and one would be rather lucky if this would happen to coincide with the proper tension required for this particular speaker.

The way I see it.

P.S. This is heat setting of the film, not to be confused with heat shrinking!
  Reply With Quote
Old 4th July 2008, 12:39 PM   #26
diyAudio Member
 
Join Date: Apr 2005
Location: Utrecht
Hi A-J

That's an interesting method. Are there any specific benefits?
Maybe a more uniform distribution of the tension?
__________________
drs M.J. Dijkstra
  Reply With Quote
Old 4th July 2008, 01:45 PM   #27
diyAudio Member
 
Join Date: Nov 2002
Location: UK
A-J

As I understand it mylar will either shrink (within its limitations) to a specific tension, or it will stretch to that same tension if it is already under greater mechanical tension. Either way, under heat it will shrink or stretch to this specific tension. So can you please explain how a greater tension than that achieved by heatshrinking alone can be obtained using heat and mechanical tension as the same time if the application of heat is constantly 'resetting' the mylar to its specific tension, for example with the Quad 63 where a higher tension is necessary?

Tim.
  Reply With Quote
Old 4th July 2008, 02:20 PM   #28
diyAudio Member
 
Join Date: May 2006
Location: Netherlands
Quote:
Originally posted by MJ Dijkstra

That's an interesting method. Are there any specific benefits?
Maybe a more uniform distribution of the tension?
There are two distinct advantages that I know of:

1. It sounds better. Supposedly because of the relief of odd tensions caused by mechanical stretching.
2. It stabalizes and strengthens the film so it can hold it's exact tension for decades.

This is why you won't find a Quad panel with a slackened film, not even if it's 40 years old.
  Reply With Quote
Old 4th July 2008, 10:31 PM   #29
Calvin is offline Calvin  Germany
diyAudio Member
 
Calvin's Avatar
 
Join Date: Nov 2004
Location: close to Basel
Hi,

Q: Who?
A: Acoustat, Capaciti, Purist and probablely some more

The rest has already been explained by AJ.

jauu
Calvin
  Reply With Quote
Old 19th July 2008, 11:39 PM   #30
diyAudio Member
 
Join Date: Nov 2002
Location: UK
Perhaps worth pointing out is a slight design weakness in the Final 0.3 - the self adhesive strips of tape running down the inside of the rear stator (presumably there to offer some 'resistance' to the diaphragm at its resonant frequency) are not stuck on particularly well. Close inspection reveals adhesion only at the points where the stator is at its thickest at five tiny points around each perforation. Most of the tape's area is unattached to the stator. The tape has a tendency to vibrate loudly on occasions, this can be simulated by blowing on it.

Tim.
  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
final 80 repair pschroth Planars & Exotics 13 30th July 2008 11:59 PM
the final attempt at audio buddhahood is finished... pics!! Audiophilenoob Multi-Way 77 14th September 2005 05:42 PM


New To Site? Need Help?

All times are GMT. The time now is 07:56 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