Go Back   Home > Forums > >
Home Forums Rules Articles diyAudio Store Blogs Gallery Wiki Register Donations FAQ Calendar Search Today's Posts Mark Forums Read

Construction Tips Construction techniques and tips

"Magnet slipped" says the Expert; Surround Repair; Poor sound now
"Magnet slipped" says the Expert; Surround Repair; Poor sound now
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
Thread Tools Search this Thread
Old 2nd March 2011, 06:41 PM   #11
tinitus is offline tinitus  Europe
diyAudio Moderator R.I.P.
Join Date: Nov 2005
"Magnet slipped" says the Expert; Surround Repair; Poor sound now
Originally Posted by JMFahey View Post

If you pull Alnico from its frame, it loses 60 to 90% of its magnetism, that's what happened to you.
I'm not sure alnico's like the shock from hard bumps either

apart from that, maybe also way too much glue between magnet and poles
optimally you need metal to metal contact
  Reply With Quote
Old 24th July 2012, 01:06 PM   #12
coffeebot is offline coffeebot  United States
diyAudio Member
Join Date: Apr 2012
Send a message via Yahoo to coffeebot
I've used an auto body hammer (plastic ends) to tap the magnet realigned before. that's why I recently purchased a pair of Polk Monitor 4 at the thrift store ($7) when I knew they had been dropped. the cones aren't moving but they are putting out weak midrange. I'll check back after I remove the cone dust cover and begin centering it again!
  Reply With Quote
Old 23rd October 2012, 05:23 AM   #13
GeorgeBoles is offline GeorgeBoles  Australia
diyAudio Member
GeorgeBoles's Avatar
Join Date: Mar 2004
Location: Australia
Just harking back to this old thread.

I made a little Hall Effect sensor (glued the sensor onto the end of 6mm dowel), and plugged it into my multimeter. The voltage from the Hall sensor as I passed it through the vent at the rear of the speaker magnet) from the "damaged" speaker was about 60 or 65% of the voltage developed by the good speaker.

That explains the poor performance of this speaker. I must now bid it farewell.

Chaps, many, many thanks for the excellent and detailed information you have provided to me. Looking at one or two of the posts it looks like some of you must have worked in a speaker manufacturing company. Very impressive.


P.S. Farmer Jack, my avatar is Sergent Schultz, who knew "nothing, nothing!"
My Website - borne out of frustration, but expanded for fun.
DIY HiFi, Combat Flight Sims & some stolen antiques
  Reply With Quote
Old 23rd October 2012, 01:35 PM   #14
JMFahey is offline JMFahey  Argentina
diyAudio Member
JMFahey's Avatar
Join Date: Mar 2009
Location: Buenos Aires - Argentina
Well, considering it *is* a JBL, maybe you might make one last effort.
I see you are in Australia.
Where exactly is anybody's guess
I know that there used to be a few speaker factories; at least one ("ex-Celestion branch?) is often mentioned as still active, although quite reduced in size.
Any factory needs a magnetizer.
Maybe you can contact one and send the speaker to be remagnetized for a small fee.
When I started making speakers, I always visited one of them, with no pressure, abig smile and, just by "sheer chance", a couple of "longnecks" under my arm.
"Longneck" being slang for a bottle of *good* wine.
Never failed.
  Reply With Quote


"Magnet slipped" says the Expert; Surround Repair; Poor sound nowHide 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

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
Is it possible to repair nakamichi cd pickup "home" laser? whiterabbit Car Audio 78 23rd July 2015 07:12 AM
"planet audio" 1250w d amp repair, need cross for cap ppia600 Car Audio 3 11th January 2009 11:48 PM
looking for a small 2" or 3" driver with poor bass response space-cake Full Range 3 27th December 2007 02:16 AM
"Kit" for Wireless Surround? sdclc126 Multi-Way 2 31st August 2007 02:33 PM
How to get rid of "CKK" Sound on "turn off" riotubes Parts 0 25th November 2006 04:50 PM

New To Site? Need Help?

All times are GMT. The time now is 03:21 PM.

Search Engine Optimisation provided by DragonByte SEO (Pro) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.
Resources saved on this page: MySQL 15.00%
vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.
Copyright ©1999-2017 diyAudio