Question for speaker experts on slight mounting hole deformations

[redking]

I have recently acquired some Celestion G12-65's that have been pulled from a stock Marshall cabinet and as is the case with many used speakers, there is slight deformation around the mounting holes. My questions are:

- How do you know when these small deformations have negatively impacted the speaker's sound and performance?
- What should I be looking for sound wise, or performance wise as a potential problem of the basket becoming too deformed around the mounting holes?
- If they are not causing a noticeable problem, should I just leave them alone?
- What are some tips to prevent creating excess speaker deformation when installing speakers in a cab? I was thinking rubber washers around the mounting screw might help, but it might have the opposite impact - I don't know.

Thanks!

 

[cooljuk]

Coil rub is likely to be the first sign of a problem. The basket becomes deformed into more of an oval than a circle. I’ve also corrected this with bar clamps, completely curing coil rub.

If you don’t have coil rub, and it sounds good and is in good shape, run it!

If you hang it in the cab upside down from how it previously was mounted, you’ll let any further knocking around on the road exert forces in the opposite direction.

PS - Not a speaker expert. Just a speaker enthusiast and tinkerer.

 

[cooljuk]

Oh, another thought - skip the rubber washers. Mount it as the manufacturer intended.

Could be that the holes got banged up from the mounting nuts coming loose and the speaker having room to slide on the baffle a little. I just hand tighten with a socket (no wrench, just the actual socket to grip the nut) and I’ve used LokTite. I’ve also had LokTite cause a problem where removing the nut caused the stud to spin the the baffle (chipboard baffle / 60s Fender) so I might try to find something a little weaker or solvent dissolvable next time. On a solid baffle with quality studs, it shouldn’t be an issue.

 

[redking]

Great info - thanks for the response. I did a quick check for speaker rub and everything seems fine - I will try to load them up and test on the weekend.

Found this as a quick resource.