Oops sorry - the rods are wood dowel (hardwood). I cut them pretty precisely to length - usually just a tiny bit shorter than the distance between pads, so the glue isn't all wiped off when I put them in place. The screw tension is enough to squeeze out most of the glue, and make a really strong joint. That also puts the rod in a bit of tension, which helps keep it straight. Usually, I have rods from side to side, and top to bottom. The front panel is hard to do this to (usually there's a speaker there, and I like having the back removable), so I use different bracing for the front and back panels.
Enjoy the benefits of a premium membership!
Upgrade Account
-
TalkBass has been independent since 1998. Add your voice.
Create a free account to reply to discussions, view embedded media, and browse with fewer display ads.
Join free Log in
Want zero display ads or expanded classifieds tools? Compare plans.
Need assistance with Amp/Cab vibrations
- Thread starter JDLowEnd
- Start date
-
- Tags
- assistance
Oops sorry - the rods are wood dowel (hardwood). I cut them pretty precisely to length - usually just a tiny bit shorter than the distance between pads, so the glue isn't all wiped off when I put them in place. The screw tension is enough to squeeze out most of the glue, and make a really strong joint. That also puts the rod in a bit of tension, which helps keep it straight. Usually, I have rods from side to side, and top to bottom. The front panel is hard to do this to (usually there's a speaker there, and I like having the back removable), so I use different bracing for the front and back panels.
My wife picked up a couple toddler sized body surfing foam thingies at the dollar store, for, well a dollar each I guess. I bring em along for stage isolation, but they would probably work for head to cab isolation too.
I put felt pads on the bottom of my amp, extra vibration to the head (tubes or not) seems like an unnecessary wear and tear situation.
I put felt pads on the bottom of my amp, extra vibration to the head (tubes or not) seems like an unnecessary wear and tear situation.
Cabs flex like anything else flexing
In the middle between the longest length.
Find the longest length brace the middle. Of whatever side your looking at.
Rear panel usually biggest culprit
Then side side
Top bottom
Use dowels or tell builder to fix it.
X brace works as well since front to rear kinda has speaker in the way. Difficult to address likewise just as easy. But important to address the rear panel
In the middle between the longest length.
Find the longest length brace the middle. Of whatever side your looking at.
Rear panel usually biggest culprit
Then side side
Top bottom
Use dowels or tell builder to fix it.
X brace works as well since front to rear kinda has speaker in the way. Difficult to address likewise just as easy. But important to address the rear panel
Last edited:
- Apr 18, 2008
- 16,004
- 1
- 31,696
- Disclosures
- I'm highly opinionated and extremely self-assured
Your amp has big feet -- you could screw castor cups to the top of the cab for the feet to sit in, then all the vibrations in the world won't make the amp go anywhere.
For a hidden look, there are recessed ones called foot cups or something like that. Cab parts suppliers carry them.
If you don't want to mod the amp, you've got a lot of options in the thread above.
Good luck!
For a hidden look, there are recessed ones called foot cups or something like that. Cab parts suppliers carry them.
If you don't want to mod the amp, you've got a lot of options in the thread above.
Good luck!
I bought it second hand so I don't know who built it. It looks authentic from the photos I have seen. Tapping the panels gives a relatively high pitch so I think it is braced properly. My assumption is the movement is because of the light weight and the powerful speakers. The cab is very light for its size. Also it's sitting on a wood floor, so some of the movement may be the building. It's not unusual for light (well braced) bass speakers to move around on the floor.
I did try to peak inside awhile back by removing the side handles, but some sort of adhesive was applied in addition to the screws. I believe the adhesive is the type used for sealing/damping not structural strength...so I didn't want to break the seal and get a bunch of buzz or leaks.
I have some old BFI branded cabs loaded with EVM18Bs. They cabs were made of thin low grade plywood with no bracing. Before bracing, the spring loaded handles would vibrate at relatively low volumes. I installed tension braces from top to bottom to rear, and also side to side. With the braces, the handle vibration stopped and the sound changed significantly.
It's been awhile since I installed the braces, but this is how I remember the sound changing: No braces. These cabs sounded really woolly with a lot of low mids and did not project very well. The low end seemed to fall away quickly with distance instead of projecting. My guess is the low mids were from panel vibrations. With the braces the sound was thinner and tighter, but the lows seemed to throw a bit better.
Last edited:
mbelue said: ↑
Your Dually vibrates that much? Who built it? Have you talked to the builder about it?
I wanted to give an update, so people don't get the wrong idea about the Dually. The vibration problem I was having was definitely the wood structure of the building moving around from sympathetic vibrations. With the Dually on a concrete slab, the cabinet hardly vibrates at all, so it is well braced.
Your Dually vibrates that much? Who built it? Have you talked to the builder about it?
I wanted to give an update, so people don't get the wrong idea about the Dually. The vibration problem I was having was definitely the wood structure of the building moving around from sympathetic vibrations. With the Dually on a concrete slab, the cabinet hardly vibrates at all, so it is well braced.
Al Kraft
Supporting Member
- May 2, 2016
- 10,768
- 40,433
- Disclosures
- Mesa Boogie beta product tester and player support
I'm still trying to wrap my head around a speaker cab vibrating so much that a 75 pound head (with presumably rubber feet and not PTFE coated disks) is moving around so much.
In my case, the head wasn't dancing around on the cab. The problem was the output tubes were vibrating in the tube sockets and losing continuity...which is a big no no. When I placed my hand on top of the speaker I could really feel strong vibrations. The vibrations seem much less intense with the speaker on a concrete foundation.
A supplement on cabinet vibration. My lightweight homebuilt cabinet was vibrating and even buzzing on the rear panel, and persisted even when I replaced my original bracing with a substantial thickness of MDF. The panel was screwed in place with what I thought was a very generous number of screws. Finally glued it in place and solved it completely.
Previous cab had been much larger with a large and long shelf port: this one has 4 tubular ones. Construction was so very different as to make comparisons almost meaningless, but my vague impression was that in spite of much smaller panel sizes the small cab was more problematic. Might one guess pressure changes were greater in the smaller volume?
Previous cab had been much larger with a large and long shelf port: this one has 4 tubular ones. Construction was so very different as to make comparisons almost meaningless, but my vague impression was that in spite of much smaller panel sizes the small cab was more problematic. Might one guess pressure changes were greater in the smaller volume?
- Feb 12, 2006
- 60,953
- 5
- 220,608
- Disclosures
- Development Engineer-Mesa Boogie, Development Engineer-Genzler (pedals), Product Support-Genz Benz
Indeed: but I did at least route it out into cells (all different sizes), so it was about a third of the weight of a solid block. With hindsight, if I'd glued the back on from the start then the original plywood bracing would probably have been good enough. The removable back was awfully convenient when tuning internal damping though.Adding MDF to a light weight cabinet is like adding lead to a light weight amp
- Apr 18, 2008
- 16,004
- 1
- 31,696
- Disclosures
- I'm highly opinionated and extremely self-assured
There’s a simple solution, put the head on the floor, sit on the cab.
All that cabinet vibration is energy that’s being wasted and not being directed out the cone.
It’s possible that the front baffle is too thin and the speaker is causing it to vibrate too much. Replacing the baffle with 13 ply baltic birch will help if this is the case. Sometimes easier said than done.
All that cabinet vibration is energy that’s being wasted and not being directed out the cone.
It’s possible that the front baffle is too thin and the speaker is causing it to vibrate too much. Replacing the baffle with 13 ply baltic birch will help if this is the case. Sometimes easier said than done.
The motive force applied by the voice coils is enough to move driver cones back and forth a quarter inch or more in each direction, so it's not hard to see why the pressure generated by that cone movement can make the cab panels vibrate back and forth by 1/32 inch, which is plenty to cause a head to move about. Bracing like that in the thread I linked to a few posts back can eliminate panel vibration, or at least make it so slight that even a ten pound amp won't move around. Thicker panels work too, but at the cost of weight. One brace connecting the middles of a pair of 1/2 inch thick panels is the equivalent of using 1 inch thick panels. Three braces spaced equally is the equivalent of using 2 inch thick panels.
I used some MDF slats in a couple of old crappy cabinets to apply tension to the panels. I cut the slats to be slightly short and then used some L-brackets to screw the slats to the cabinet panels. The slats pulled apart with a lot less force than I expected, which leads me to question the structural integrity of MDF.
Al Kraft
Supporting Member
- May 2, 2016
- 10,768
- 40,433
- Disclosures
- Mesa Boogie beta product tester and player support
Which is kind of where I was getting hung up Rick...I've just never owned an oddly (I'm being kind) designed/built cab where this kind of problem existed. On all my cabs, a 6 pound head pretty much stays put.
The Dually is exceptionally light, and I think the light weight contributes to the problem...and possibly even contributes to the Dually's vintage tone.
But since the cab vibrates a lot less on a concrete floor I don't think the cab is totally to blame. I suspect sympathetic vibrations in the structure of the house get the floor moving pretty good, and then the carpet allows the cab to vibrate even more.
I do think isolating the amp from the cab is a good idea, especially with a tube amp. I have been looking for a nice small folding table that is rated for at least 100lbs. Basically a heavy-duty folding dining table or camp table. So far the highest rating I have found in the right size is about 65lbs. I have also considered a QuikLok WS 540 and a piece of plywood.
