Annoying Amp Buzz on “G” and “D” notes

[BassManDan14]

Last night I noticed my amp buzzed loudly when I played a “G” or “D” note in any octave (every other pitch sounds great). It just started happening last night. I was using an SWR 2/10 cab and a Workingman Peavey Head. I tried 3 basses with and got the same result. I then tested my Fender Bassman 250 amp and it had no buzzing at all.

 

Is it a blown speaker cab, something loose in the head, or just an odd sympathetic vibration?

 

Any ideas on what is causing this buzzing and how to fix it?

[WRGKMC]

That typically happens when you have something physically loose in the cab. When you hit a specific note it causes the cab to resonate and whatever is loose vibrates independently with the rest of the cab. The effect is called sympathetic vibration.

 

What you need to do is baton down all the parts that can move on the cab. First make sure the speakers are right. Unwanted air leakage can change the cabs normal resonant frequency. Also check any and all hardware screws and especially the baffle and covers. Bass cabs produce low frequencies and tend to walk screws loose with the vibrations. I own several older bass cabs and had allot of issues with unwanted vibrations. One had rubber coated spring loaded handles that were worn and vibrated badly. I took them off and sprayed them down with that rubber spray paint and that fixed the issue for good. Another had a port panel that had come unglued so I re-glued it then calked all its interior joints with 100% silicone calk and the problems never came back. Sound was much tighter too. That cab was pretty beat up on the outside so several of its seams likely had problems.

 

Many of those SWR cabs have those big metal grills. I'd focus on that grill like a laser as being the culprit. I've had several bad experiences with metal grills vibrating and making all kinds of racket. the most recent being a Traynor cab a friend gave me. I loaded it with speakers and tried using those metal covers but even after all kinds of mods using rubber washers and calking I couldn't get rid at the noise that kept coming back. I eventually dumped them and built a decent frame and use grill cloth and the units held in place with Velcro strips. dead quiet now.

 

You want to make sure your speaker surrounds are good too. Buzzes are the first symptom of then tearing. You can patch them with that flexible speaker glue if you catch them early. Otherwise you wind up having to re-cone or replace them. The dust caps can come loose and buzz too. Those can typically be tacked back down with glue too. You should only used speaker glue designed for that purpose. Its sold by the ounce and has a brush applicator.

[DeepEnd]

WRGKMC is telling it to you straight. Do a visual inspection of the cab and see if anything appears loose, damaged, etc. Get down next to it and play the notes on your bass and see if you can tell where the buzzing is coming from. You may have to check inside the cab. Once you know what's making the buzz you can figure out how to fix it. If you need help post back and let us know what the problem seems to be.

 

[BassManDan14]

Thanks you! You called it. The metal grill was the culprit. I put pressure on the grill and buzzing was not as bad. The screws were very tight already. So removed the grill and it was buzz free. I then put skinny rubber washers to help absorb the rattling and it worked perfectly.

[BassManDan14]

It was the metal grill that was causing the buzzing on the “G” and “D” notes. Problem solved. Thanks!

[WRGKMC]

Glad to hear you fixed it.

 

Metal Grills can prevent speaker punctures but they typically suck for noise, especially on a bass cab.

 

If the problem comes back you cant try some foam tape or weather stripping in back of the edges to absorb vibrations.