212AV with obnoxious buzz, can’t trace, HELP,,,

[byacey]

Unfortunately I am not going to be able to return it. Looks like I got stuck with a lemon. Maybe I’ll get lucky and find someone selling one for cheap that doesn’t have the same issues, and I can part this one out, or keep the spare speakers, grille, etc. in case I pop a speaker or rip the grille. Of course I will do all I can think of, even if it starts to ruin it cosmetically to try to make it useable before I spend any money on another. And, if it gets to that, I am bringing an amp and playing it loud before I buy.

Before throwing in the towel, why don't you open it up and see what is actually loose? I'm willing to bet that it's a simple fix once you find the problem.

Edit: I doubt you'll need to deface the cosmetics of the cabinet either. Likely it's some internal loose / inadequate bracing or glue joints.

 

[AlexanderB]

I have not one, but TWO american made SVT-210HE with delaminating/defective plywood and sloppily made joints in the baffle. Extra glue and additional bracing cured the problem.
Have never seen this on any other bass cab, not even cheap Behringer stuff.

A chinese made BA110 V1 combo I opened up was the worst made MI product I have ever seen, especially the cabinet.

As for Fender, I see the tolex peeling off, lifting from the wood, on new flagship Super Bassman and Bassman floor models at the local MI shop.
Again, never seen this on even the low end Behringer or Bugera amps.

 

[tchristian]

I like your idea for squeezing the box. You might get the same effect by cutting a wooden brace to fit tight so it exerts outward pressure. No visible impact that way.

You might also run a generous bead of silicone along the inside seams.

Don't give up.

 

[Dirk Diggler]

Remove the handle and prove your hypothesis.
If it's removed and still makes the noise, you've got other issues.

Noises like you describe are usually from wood or screws moving with sympathetic vibrations.
You will need to find the offending area and perhaps reglue or secure the area.

Or you could just never play an A @ 440, LOL just joking.

Good luck,
Dirk

 

[Skillet]

Remove the handle and prove your hypothesis.
If it's removed and still makes the noise, you've got other issues.

Noises like you describe are usually from wood or screws moving with sympathetic vibrations.
You will need to find the offending area and perhaps reglue or secure the area.

Or you could just never play an A @ 440, LOL just joking.

Good luck,
Dirk

From the OP's first paragraph, "...Yesterday I took to jam with some guys and now today I have it on at a rather low volume and I have an OBNOXIOUS buzz exactly at A/440. If I simply grab the side handle and twist, it will go away, but it isn’t the handle as I have it removed now and the buzz is still there..."

 

[Lammchop93]

I had this exact problem with my 212av. There is a brace that runs front to back dead center of the cabinet between the 2 speakers. Take a 1.5-2" wood screw and drill it right in the center and it will tighten that brace. If you want to see what I am talking about, remove the speaker and you will see it in the dead center of the cab.

 

[Ringhammer]

Before throwing in the towel, why don't you open it up and see what is actually loose? I'm willing to bet that it's a simple fix once you find the problem.

Edit: I doubt you'll need to deface the cosmetics of the cabinet either. Likely it's some internal loose / inadequate bracing or glue joints.

I have opened it up, removed one handle and one speaker, and found nothing obvious loose inside. Also, this is a buzz, not a rattle or vibration. It is a bizarre issue where, when testing at low volumes it goes away when pressing certain spots, like near the handle, but as I said, looking at the plywood at the handle cutouts I can’t see any obvious problem.

I will definitely be trying all I can do to resolve the problem, working from the inside out, doing all I can to not alter the cosmetics with screws or whatever, but it sucks because I have enough to do as it is, and this feels like it has the potential to be terribly frustrating.

 

[Ringhammer]

I had this exact problem with my 212av. There is a brace that runs front to back dead center of the cabinet between the 2 speakers. Take a 1.5-2" wood screw and drill it right in the center and it will tighten that brace. If you want to see what I am talking about, remove the speaker and you will see it in the dead center of the cab.

Will this mean drilling a screw in at the each end of that brace from the outside (rear) and through the baffle? Any pics? This is hopeful…

 

[Lammchop93]

Will this mean drilling a screw in at the each end of that brace from the outside (rear) and through the baffle? Any pics? This is hopeful…

i dont have the cab anymore, but I just did one screw through the front. Once you take off the grille, you can unscrew a speaker and youll see the brace, so you can get a feel of where to screw in. ill try and find a google pic, but not sure if anything will come up

 

[Lammchop93]

i dont have the cab anymore, but I just did one screw through the front. Once you take off the grille, you can unscrew a speaker and youll see the brace, so you can get a feel of where to screw in. ill try and find a google pic, but not sure if anything will come up

If memory serves me right, the screw was where I marked the red spot. you may be able to stick your hand through one of the ports and feel for it. it's a 1x1 or 2x2 brace that runs front to back, and was glued/stapled in place. I guess it's not center like I said, but I am going off of memory.

 

[Ringhammer]

Your description is good, just wanted to be clear if you drove a screw into both ends of the brace.

 

[Lammchop93]

Your description is good, just wanted to be clear if you drove a screw into both ends of the brace.

if you wanted to test anything prior to screwing, push in on that area of the baffle when playing a note, and see if the noise stops. that, or reach into the cab through the port and hold the brace to see if it stops. that's how I diagnosed it.

 

[byacey]

Ideally you want to drive the speaker with a variable oscillator tone, so you can zero in on the offending frequency and have a steady condition for locating what's rattling. If you're going to fasten down anything, use PL glue in the joint before you drive any screws or nails. Once it sets, it forms a solid, gap filling glue joint that won't allow any chance of loosening up.

 

[byacey]

If memory serves me right, the screw was where I marked the red spot. you may be able to stick your hand through one of the ports and feel for it. it's a 1x1 or 2x2 brace that runs front to back, and was glued/stapled in place. I guess it's not center like I said, but I am going off of memory.

It wouldn't hurt to add another brace in the triangle area formed between the tweeter and the two bass drivers. Because of the way they placed the 12s, the baffle board is quite weak in that area.

 

[Jeff Scott]

I did discover that at higher volume when I push kinda hard on the back, a lot of the buzz is reduced or eliminated. I’ll keep playing with it, but my current thinking is I can possible find a way to support the back panel better somehow.

Same cabinet, same problem. Please post whatever diagnosis and/or solution you find!

Before throwing in the towel, why don't you open it up and see what is actually loose? I'm willing to bet that it's a simple fix once you find the problem.

Edit: I doubt you'll need to deface the cosmetics of the cabinet either. Likely it's some internal loose / inadequate bracing or glue joints.

I like your idea for squeezing the box. You might get the same effect by cutting a wooden brace to fit tight so it exerts outward pressure. No visible impact that way.

You might also run a generous bead of silicone along the inside seams.

Don't give up.

I had this exact problem with my 212av. There is a brace that runs front to back dead center of the cabinet between the 2 speakers. Take a 1.5-2" wood screw and drill it right in the center and it will tighten that brace. If you want to see what I am talking about, remove the speaker and you will see it in the dead center of the cab.

If memory serves me right, the screw was where I marked the red spot. you may be able to stick your hand through one of the ports and feel for it. it's a 1x1 or 2x2 brace that runs front to back, and was glued/stapled in place. I guess it's not center like I said, but I am going off of memory.

Just glancing through this, the idea of loose/inadequate/improper bracing seems to be the culprit. Can more bracing be added to apply outward pressure on the cabinet walls?

 

[byacey]

You don't really want outward pressure being applied to the walls of the cabinets. The idea of bracing is to tie the walls together to make the sides, back and baffle board more rigid, so they can't flex inwards or outwards. If something can flex, it will vibrate.

 

[Ringhammer]

What’s PL glue?

all great ideas that I will apply, this forum is a lifesaver. The added brace certainly can’t hurt if I am sure to do,it correctly.

 

[Jhass]

Are you able to access the port tube, and apply pressure to it while playing that A to see if the buzzing stops? I have a cab (different brand) that is making a buzz at specific "D" frequencies, and I've traced it to the port tube. The fix will be to remove the port tube and re-install with fresh sealant, but my cab has a metal grill held on with about 20 screws so it is easy (although tedious) to remove the grill. I don't know how Ampeg attaches the grill on their cabs

 

[byacey]

What’s PL glue?

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[Jeff Scott]

You don't really want outward pressure being applied to the walls of the cabinets. The idea of bracing is to tie the walls together to make the sides, back and baffle board more rigid, so they can't flex inwards or outwards. If something can flex, it will vibrate.

Okay, makes sense. I was just thinking about a review I read many moons ago on Acme cabinets and their wedging in of their braces, (IIRC).