Tube Amp Archive

Anyone have any tips on how to alleviate the issue of cab noise/resonation? I tried adding some mahogany panels inside one of my small 600 cabs and this didn't seem to change anything. I guess it wasn't enough added mass to make any difference. Is there some interesting method that I don't know about? Any help would be great.

DK

Preload, either to the back of the magnet, or side to side.

Cut some 1x1 and wedge it in, see what happens.

John

Sometimes I use Mortite, available at the home despot. It can reduce the resonant frequency. On my 2 12 cab I used sound posts and braces like in a guitar and violin. Also used asphalt flashing around tube ports to quell the resonate ring. Some noise can be from crappy plywood, some from poorly sealed joints, air leaks etc. I also have used Mortite on the speaker frame to reduce ringing . I have other methods I use on speakers like the European wrapping around frame spokes etc.

Yes a front to back "stiffiner" would help...what are the demensions and what is the cab constructed of?

Point loading a resonant panel really only moves the resonance, as any panel will resonate longitudinally and transversal much as a guitar string.
Point bracing at the middle only creates a 2nd harmonic point.
Heavier mass or diagonal bracing is much more effective.... if you eant to go really bonkers, then connect the panels.
Heavy bitumen panels also dampens resonances....

Thanks for the tips fellas. I'm not sure what the cab is actually made out of, but I think it's the same shit the new blackface Fenders are made out of. The cab is the standard Champion 600. Finally got the tone I was after with this thing with Weber's Signature 6" and OS tubes and it starts resonating like this...

I did a clip of the amp hoping to capture the resonation, but you guys tell me if you can hear it. I think it comes through a little, but you tell me. It's just a bit of noodling, mostly on the notes where it seems to be worst, and in between, just some guitfiddle wanking.

FWIW, I like the tone. What you are calling resonance is the buzz type sound that occurs while some notes are sustaining, correct? That sounds very similar to what I have experienced with some combos. My first guess would be cab/chassis rattle. Does it happen if you remove the head from the cab? I am guessing that it doesn't. IME, it is usually some part of the cab buzzing against the chassis or faceplate at certain frequencies. I've been able to cure this with weather stripping or by sliding the chassis around inside the cab and attaching it in a slightly different position. I usually hold notes and use my free hand to 'damp' parts of the cab until I find the location of the buzz i.e. I feel around for it.

vibratoking wrote:FWIW, I like the tone. What you are calling resonance is the buzz type sound that occurs while some notes are sustaining, correct? That sounds very similar to what I have experienced with some combos. My first guess would be cab/chassis rattle. Does it happen if you remove the head from the cab? I am guessing that it doesn't. IME, it is usually some part of the cab buzzing against the chassis or faceplate at certain frequencies. I've been able to cure this with weather stripping or by sliding the chassis around inside the cab and attaching it in a slightly different position. I usually hold notes and use my free hand to 'damp' parts of the cab until I find the location of the buzz i.e. I feel around for it.

Thanks VK. I posted some longer ones in the Fender section if you or anyone else is interested and just used this shorter one for reference here.

About the noise... I thought the same thing and did a myriad tests to isolate the issue, including removing the chassis and playing, retightening the speaker and even trying the other amp through it. The cab itself does indeed buzz/resonate on its own. I'll end up trying one or two of the suggestions above and you make a good point about weather stripping. This amp has had chassis rattle at times, but it's not nearly as prevalent as the cab's resonance.

I have been tempted to build a thin walled speaker cab for not particular reason other to scratch an itch. I thought I would reinforce the walls similar to what is done in an acoustic guitar - interlocking beams/struts [don't know what the correct term is]. They run out to the edge in every direction and would give more radial support to tame the resonance.

Russ

Sometimes polyfill wadding like this:http://www.mcmelectronics.com/product/L ... 5404212667

can be stapled inside one or both side panels, and it will be enough to stop the resonance.

With closed-back cabs, you can buy a polyester filled pillow from Wal-Mart for about $4 and take the inside stuffing out and stuff it in the cab.

For an open back, that's not such a great solution when the stuffing starts coming out of the rear hole.

I've used the insides of an old couch cushion, cut smaller with scissors, and stapled to one side of the cab, and I got lucky and it worked.

If you have any of that recording studio foam, it may work also, stapled to one or both sides.

Stay away from fiberglass - it's nasty

When designing new cabs, use the golden ratio for dimensions, and you won't get resonance in the first place, because this ratio prevents standing waves.

Geeze:


This was my try.

John

Come on now John, you tease. How did it sound? How much did it weigh?

That is a clever design and wood work.

Russ

That's a beautiful box right there. I've not yet had a chance to try any of the above methods, but plan to.

I'm not entirely sure what you meant in your first post, John, regarding the 1/1 wedge. Sorry if I'm being dense.

Cantplay wrote:Geeze:


This was my try.

John

I've never seen anything like that. It sure looks fantastic. How does it sound? What driver works best in it?