Hi guys, very long shot here but:
I’ve been using the Sound City SC212 as my main cab for about 5 years now. I’ve often struggled with what I assumed where just sympathetic vibrations with the cab no matter which amp I use with it. I thought it was the badge, so I removed that. No dice. I thought maybe I had a voice coil issue in one of my speakers, but they both tested perfectly. I then tightened every screw around the cab. Still buzzing. So, last night, I put the cab facing face down on my bed, plugged up a 50w Plexi, cranked it, and chugged away while pressing on the back panel. I was able to finally make the buzzing stop by pressing down firmly on the center of the back panel.
Any idea for a permanent fix for this issue?
Thanks in advance.
Welcome to the forum!
That’s an interesting observation.
This cab doesn’t have a sound post inside like some cabs do. Adding one would stabilize the rear panel, but would also stiffen the sound.
The baffle has a V-Brace to break up resonances, so the cab isn’t a sloppy mess. And there is a bottom rear vent that allows low end energy to dissipate.
I guess if you want to tame or eliminate that rear cover resonance, you probably need to add a sound post. That would be in the form of a 2x2 that runs the distance from the baffle to the rear cover.
Adding a piece like this is a bit of an art, so if you’re not experienced with things like this, you may want a cab guy to do it. For example, the post would have to be roughly 1/16" longer than the internal distance to make a solid connection to the back cover. Also, it will change the character of the cab in other unpredictable ways.
Dave
Thanks for chiming in Dave. I was sort of hoping that wouldn’t be the final answer haha but, it’s not totally unexpected. I’ve read some tips about potentially adding more mass to the back panel as well to combat this issue. Any ideas about that one? I’ve seen some people say that adding a wooden “stiffening cleat” would help, while others suggest automotive sound deadening material.
I’ve seen some suggestions of weather stripping around the inner lip on the back panel but this one feels less likely to solve the problem, but maybe I’m wrong.
Adding mass to the back cover is definitely an option I would consider.
That would effectively raise the resonant peak of the cover making it less likely to “ring” at the frequency that is driving it now. Of course, it might be more sensitive to a higher frequency, but would probably be less audible.
Something like a 1x2 vertically or horizontally across the panel would do it. Horizontally would increase the resonant frequency more than vertically.
I spent the morning installing a piece of solid wood across the back panel. Once the glue has fully cured and I get the cab reassembled, I’ll report back on whether or not this helped the issue.
Well, after all of that, the extra mass on the back did help with the back panel vibrating. So that’s good. But, it also helped to isolate the annoying buzz that I originally assumed to be the badge - and made me realize that the grill cloth itself is flapping against the front baffle and buzzing on certain notes. I took the cab back apart, tried to add some foam along the front baffle where I could hear the buzzing, but no dice on that one either. I think I’m simply at the end of my rope as far as trying to fix my annoyances with this cab. I spent a lot of money on it due to the fact that I’ve been burned on so many cabs in the past, and aside from the fact that it has great speakers in it, the cab itself has been more of a hindrance than anything else. I think it’s just time to move it along at a loss and let it be someone else’s problem.
Thanks for the report and the time you spent drilling down on this.
Grill cloth slap is a thing that players hear occasionally, but are rarely concerned about. That’s the down side of stretching the fabric so that it doesn’t sag and look like crap after a year or so.
How about this: If you’re not fully exhausted with this, you could send just the baffle here and we’ll replace the grill and add a layer of felt between the fabric and baffle to damp the slap.
No charge and we’ll pay the return freight.
If that sounds doable, email me at support@fryette.com and I’ll set it up.
Thanks,
Dave