Question about buzzing cab

[BigHome]

Hello all, advice needed...

recently got a new amp that is 50 watts greater than my cab... 450 head and 400 cab. Since i've been playing with that head and a VT Bass pedal, the cab has started making an awful buzzing sound, like screws are loose or worse. What is causing this and how can it be remedied? Been gigging the cab for 8 + years without this issue.
thanks a ton for the advice!

[RickenBoogie]

You may be pushing it too hard, either with sheer power, or low end eq. Either way, the cabs rating is it's thermal limit, not what it'll actually do. Most cabs will get you halfway to their rating before giving out.

[bassdaddyfive]

Sometimes things shake loose. And sometimes the speaker it's self could be the problem. I once had a buzzing in my cab from the crossover shaking loose and over heating. Cracked circuit board.........

[BigHome]

So what's the checklist for going through an amp with a buzz? I've tried tightening all the screws on the speakers, cab, etc. already and am unsure of what to address next.

[BigHome]

Anyone able to offer any advice on how to troubleshoot a buzzing cabinet?
thanks

[dmusic148]

Possibly an overheated/blown speaker. Take the grill off and very carefully push each speaker in and out, listening closely for scratchy sounds. If you hear noise, the speaker is dead and needs to be reconed or replaced.

[BigHome]

ok, i tried pushing on the speakers, they all seem perfect with no scratchy noise. is there something else that i can try to troubleshoot this?

by the way i am my cabinet is 400w and my head puts out 450 watts. i also use a vt bass, could the vt bass put the output from the head over 450 watts?

[billfitzmaurice]

Originally Posted by BigHome

by the way i am my cabinet is 400w and my head puts out 450 watts. i also use a vt bass, could the vt bass put the output from the head over 450 watts?

Moot, as the cab thermal rating is probably at least twice what the drivers can handle before exceeding their excursion limits. If there's nothing physically wrong with the cab try turning down the volume and/or the bass EQ.

[BigHome]

Originally Posted by billfitzmaurice

Moot, as the cab thermal rating is probably at least twice what the drivers can handle before exceeding their excursion limits. If there's nothing physically wrong with the cab try turning down the volume and/or the bass EQ.

thanks bill ive been playing this setup for about 8 years, but soon after i got the vt the cab started buzzing even at half volume, so i cant turn it down more for it to be usable at a gig.

[Gizmot]

Your new amp might have more output at infrasonic frequencies (below the enclosure's tuning). If the cabinet is a vented system, you have to be careful of that. When you drive a speaker (either a bass cab or a sound reinforcement/PA box), below its tuning frequency, it causes the woofers to move past their safe excursion capability. Try backing off the low EQ and see what happens.

[billfitzmaurice]

Originally Posted by BigHome

thanks bill ive been playing this setup for about 8 years, but soon after i got the vt the cab started buzzing even at half volume, so i cant turn it down more for it to be usable at a gig.

That tells me that the VT is the problem.

[MNAirHead]

Thread locker on all the fasteners.. move all TNuts to socket head cap screws.. layer of foam/sealant around all of the handles etc.

[Gizmot]

If you can, take the grille off the speaker and watch the drivers while you play. If they move too much, move erratically or don't move at all, then you'll find the problem

[punchclock]

i have a similar problem.
cab buzz.
if i press down anywhere on the baffle it goes away.
happened out of nowhere. worked fine, then the rattle appeared.
its a chinese built ampeg b200r cab & those have a history of weird shakes and stuff.
don't know if its worth trying to find someone and pay to check it out or cut my losses.