Back of (oversized) Recto 4x12 rattling on low notes

The other day I lent a bandmate my oversized 4x12 to record some guitar with. He was playing pretty loud and at one point when he'd hit low palm mutes you could hear (and see!) the back of the cab rattling against the brace. I know that's what was happening, because it stopped when I pressed against the back panel. Should probably add that this cab has EVM-12Ls in the bottom two slots, and he was using an Ampeg VH150 which has some pretty crazy low end.

Anyhow, my first instinct is to just drill a couple of holes and screw the panel to the brace from the back, but I figured I'd check in with the BB in case there's a better solution.

I would pull the back off and have a look whats going on before I did any drilling.

barryswanson said:

I would pull the back off and have a look whats going on before I did any drilling.

Click to expand...

Yeah, I took a look inside the other day - nothing unusual and the speakers are all securely bolted. It was just the back panel vibrating against the brace (which is securely anchored to the front baffle).

A friend suggested just sticking some foam on the back where the brace pushes on it. Right now the brace has a very, very thin adhesive pad on the end but that's all. That'd be easier than drilling + screwing obviously, but I'm wondering whether the two options will sound different and/or fix the problem equally well.

morgan138 said:

The other day I lent a bandmate my oversized 4x12 to record some guitar with. He was playing pretty loud and at one point when he'd hit low palm mutes you could hear (and see!) the back of the cab rattling against the brace. I know that's what was happening, because it stopped when I pressed against the back panel. Should probably add that this cab has EVM-12Ls in the bottom two slots, and he was using an Ampeg VH150 which has some pretty crazy low end.

Anyhow, my first instinct is to just drill a couple of holes and screw the panel to the brace from the back, but I figured I'd check in with the BB in case there's a better solution.

Click to expand...

Does the back flex like that at reasonable settings/levels?

I'm sure if I crank my Roadster up to extreme levels I would have the same issue running only one 4X12.

Dom

domct203 said:

Does the back flex like that at reasonable settings/levels?

Click to expand...

I've never heard it do that before. Even when it was happening, it was only if he palm muted an Eb with some specific picking hand position. We didn't even have to turn down to make the problem go away, he just stopped doing whatever weird thing he was doing and it was fine.

On the other hand, while the amp was turned up loud it wasn't anything crazy volume-wise.

I have had this problem with my Recto cab at any volume level with palm muted notes. However at elevated levels, the noise would go unnoticed. This all came about shortly after opening it up and replacing speakers. I bought the cab new in 2000 but it did not get much use until I bought a Mark V head. Now I use it with my Roadster. Replaced all of the speakers with EVM12L black label speakers. noted several things that had happened after ward and continued even after returning the stock V30's. Not only did the center post rattle against the baffle, the area between the two upper speakers was vibrating as well as was the baffle board near the bottom right front corner.

Found the support post to be loose and perhaps opening up the cabinet may have loosened it. One quick pull and it came off. Tried the cab without it, sounded terrible. Had to make a new post as the old one was in poor shape. New one was slightly longer by at least 1/16 of an inch or less. This put more pressure on the back board and cured the vibration there. Added a support from the center post to the area on the baffle that was giving me grief as well as secured the front bottom baffle board to the cabinet. Now it is tight and responsive with all noises or resonant vibrations that may occur at some frequencies. Also had issues with the grill making some noise and wound up using a compressible gasket (rubber foam seal) to arrest vibration. Also had to secure it to the baffle from the front vs the original method as the material of the grill just would not hold the screws any longer.

I also have a new oversized recto cab and it is slightly different than the older one. Never going to open up this one as it sounds great as it is.

Personally, I'd just screw some 2x1 strips down the back of the cab. It's obviously a weakness in the ply

That would work....

Also if it is just the center post, you can get some thick rubber electrical tape (it is soft and gooey and has adhesive). Put it on the end of the post one or two layers thick and it should reduce or eliminate vibration on the back board.

What I had to do to cure my cab may have been extreme but once I fixed one area, it erupted somewhere else. Now it is tight as a drum.