Celestion G12T Speaker Sizzle at low volume

[chazpope]

Hi

My Marshall speaker has suddenly developed a funny sizzle (frying eggs) sound on any notes with to low to mid frequency, tried with another amp - the same.

It sounds like normal but with an added permanent sharp sizzle clearly audible especially at low volumes when played clean. It does still deliver plenty of loud power as normal when turned up. I took it out and it looks ok mechanically, no bumps or tears all looks in order, no scratching when I move the cone. But when played it sounds as if there is a nail attached to the cone scratching on some surface.

Changing speaker will cost more than the amp is worth before it broke.

Is there anything I can do ? I stopped short of removing the coil cap to take a peak but what could it be ?

Thanks

[Jazz P Bass]

Check the spider ring & see if the glue did not dry out.
Maybe one edge is lifting.

[pdf64]

Seems like it may be voice coil rub.
Has it / the cab had a bump?
Has it been in different environmental conditions?
Ted Weber mentions a procedure for re-centering things on the Q&A Let's Talk Speakers
Pete

[The Dude]

It does sound like the voice coil is rubbing. Another cause could be tinsel leads rubbing against something as the cone moves if they have too much slack. I've seen it before albeit rarely. You could also have a chunk of glue or something rolling around under the dust cap. If there's nothing obvious on the outside, you can carefully cut off the dust cap to have a look.

Edit: Sometimes when moving the cone up and down everything seems fine. If you give the cone a good hard tap with your finger to get it moving, you might better hear a problem. The sound should be a clean thud- no "knocking" or mechanical sound. This takes a little ear training to know what to listen for, so you may want to try a known good speaker first for comparison.

[Jazz P Bass]

Watch out for metal bottle caps around the magnet.