OT-Squished speaker cone repair?

RichMacDonald wrote on 9/16/2004, 8:23 AM
This morning my 18 month old climbed onto the computer desk and in the 5 seconds before I could grab him, he stuck his finger into the cone of my M-Audio LX4 speaker and squished the convex center portion in. No tears in the cone, but otherwise completely squished in. His and my tears were another matter ;-( Luckily I have a buddy who is an audio specialist and can probably repair it, but in the 8 hours before I can talk to him I'd appreciate someone to commiserate, console, suggest, whatever. I know I can't get to the cone from the rear, so a really good vacuum that can grab the front and suck the cone back out? Or some silly putty to stick onto it and pull :-? How do you restore a cone to its convex shape? Or do you bite the bullet and recone? BTW, the speaker still sounds ok, but I haven't done a scientific test yet. And I googled this, but everyone seems to deal with more serious cone replacement and I could not find any simple fixes. TIA.

Comments

B.Verlik wrote on 9/16/2004, 1:25 PM
It may be fine. You'll need to do a comparison test with the good speaker, using a mono source that will let you know if it sounds different or not. Maybe using a spectrum analyzer will give you results that can convince you. You might still have to wait for your buddy to do this for you.
If you ask a speaker repair company, they'll probably tell you it needs to be fixed, by them. As a musician, I've used speakers with crushed cones for years and couldn't tell the difference, unless it was crushed and torn. I can't tell you for sure if you have a problem or not. A test is required.
Chienworks wrote on 9/16/2004, 2:33 PM
Personally, i wouldn't worry about it unless you can detect a noticeable difference. That part of the cone is mostly for cosmetic value, not for sonic purposes. It comprises a very small area of the entire cone. Consider also that many other speakers have flat or even convex coverings in the center.

If it's really troubling you and repair is too expensive, try very gently smoothing a small piece of duct tape onto it and then gently pulling it off. I've done this several times and had very good luck and popping it back out.
Geoff_Wood wrote on 9/16/2004, 3:42 PM
A vacuum cleaner will pull it out. Preferably one with variable suck-power and/or a bypass vent. Start on lowest suck. Mouths have been used with success on my tweeter domes....

I wouldn't worry about minor dints - it's primarily there to keep dust out.

geoff
PipelineAudio wrote on 9/16/2004, 4:41 PM
its Dustbuster time! Even better if you have the battery powered car one
tmrpro wrote on 9/16/2004, 6:31 PM
What has been damaged is the dust cover, not the speaker's cone. The speaker's cone is a cylindrical wire wound element that lives in a very tight magnetic canyon underneath the dustcover in the butt or core of the magnet.

Chances are that your speaker repair guy will suggest that you leave well enough alone, if there has not been a noticable difference in performance.
wobblyboy wrote on 9/16/2004, 6:40 PM
The center is usually a dust cover and will not effect the operation of the cone. If you can't fix it from the front you can't fix it. You would have to remove cone from magnet and you don't want to do that.
RichMacDonald wrote on 9/18/2004, 8:00 AM
Thanks for all the support. First, I agree that the problem was cosmetic and did not affect the sound in a noticeable way. But still :-)

The fix is as follows:

Cut a rectangular piece of duct tape. Hold the wide ends in two hands and press the center onto the cone so that it sticks. The tape is now in a "V" shape. Now pull the two ends apart, NOT towards you. With a bit of luck and a lot of tries, you should be able to pop the cone back out.

The key is to pop the center (dust cover) without straining the rest of the cone. If you pull the tape towards you, you wind up pulling the whole mechanism towards you and this can damage it.
wobblyboy wrote on 9/19/2004, 1:04 PM
I didn't realize that the dust cover was still intact, or I would have suggested that you do something similar to what you did. Glad it worked for you.