Speaker buzzing on low notes - help

Probably cone cry (cone rub). Sometimes mounting the speaker 180 degrees from original can eliminate it--if it's an extension cab just turn the cab upside down. If not it probably needs to be reconed.

 

This may not be the problem but I have heard that putting a "death grip" on the mounting nuts can distort the basket and possibly cause this. Just finger tighten the nuts then give them a quarter to half turn more with a nut driver. But Rob's suggestion is probably more accurate.

 

Sounds just like my spare Altec did last month....needed to be re-coned.

 

I've never heard of it helping.

 

@WineCaster, a guitar speaker I bought last year developed a frequency-dependent buzz shortly after I installed it. The cause was a small piece of hardened glue squeeze-out from when the dust cap was glued on at the factory, loose under the cap. Discovered this by gently shaking the speaker and resolved it by parting a portion of the cap away from the cone and letting the piece fall out then re-gluing. Don't know if this is as likely as a warped basket from over-tightenting or the other possible issues already mentioned. But easy to test.

 

I had this exact problem in a 68 custom Princeton RI and fixed it. If you play the offending low notes and push the face of the baffle just over the speaker does the buzz go away? It probably will . . .

If so you need to reinforce the baffle. Get some 1"x1" square profile wood trim the length of the baffle. Glue it with construction adhesive inside the baffle above the speaker. Then take about 5 wood screws and screw in the trim. Reinstall baffle and you should be good.

It is what was done here, but with wood, not metal and without a need for a router:

http://www.tdpri.com/threads/the-cure-for-princeton-reverb-cab-buzzes.170032/

 

Also, if you change out the speaker for something bassier then the problem will be worse. When I put a Eminence Lil Buddy in there it was worse. I wound up putting the stock speaker back in and thinks it works better with this circuit anyway.

 

Assuming it's not cab rattle. Sounds like a voice coil issue. Did anyone try to move the cone with their hand or other physical means? Did the screws get over torqued on the speaker when it was mounted?

 

See my posts above, but I chased this issue for 2 years, embarrassingly enough, convinced it was not cabinet buzz. I thought it was the speaker. Bought a new speaker and it was worse. If you press the top of the baffle and the buzz stops . . . it's cabinet buzz. Very easy to rule out. Push the baffle, and cabinet in different spots to easily rule that out or prove that point before going to more invasive extremes. I'll get off my soap box now.

 

My bad. Good troubleshooting though.

 

Cone cry and 'rub' are two very different things. This problem is more likely to be a voice coil rub, which can be detected with the speaker out of the cab. Olace the speaker face side up on a stable surface. Place the fingers of both hands on opposite sides of the speaker....three fingers spread so as to depress the cone----lightly please--- and then letting the cone return to its "at rest" position. If there is voice coil rub, you will hear a gritty noise as the coil moves through its path. Sometimes rotating a speaker 180 degrees will help with this....most of the time it does not help. There are steps that can be taken to realign the voice coil.....possibility of a cure. If not, the speaker needs to be reconed.
Cone cry occurs in otherwise perfectly good speakers when a strong signal is sent to the speaker with frequencies that occur above the 12th fret...usually. The cone shape distorts to create a howling that is not musical. Doping helps control this.