Head keeps rolling off my cab?

[bassgod0dmw]

Originally Posted by hover

What I think those suggesting it are missing in the bigger picture is the cab should not be displaying this symptom in the first place

Quoted for truth.

Fix the cab. Don't use velcro, a gramma pad, tool box liners, or anything else.

[B-string]

Yep!

[bryan gibson]

My drummer's cymbals are all (unintentionally) tuned to F#. Doesn't matter how loud I'm playing, that note sends his whole kit into "earthquake mode." Gotta love it

[creis2]

Yeah, I have another cab in the works with him, I might put that on hold until this one is figured out.

I did the duratex job myself (I ordered the cab bare, because I had 3/4 of a bucket unused). But I did the same with my NV610, I've never had that problem with that.

I put the gamma pad under the cab.

Velcro isn't going to solve the issue, this thing shouldn't be moving like this.

I will post a video in a few days.

[SHardin]

Just because no one else has done this yet,.,,

The property of sympathetic vibration is encountered in its direct form in room acoustics in the rattling of window panes, light shades and movable panels in the presence of very loud sounds, such as may occasionally be produced by a full organ. As these things rattle (or even if they do not audibly rattle) sound energy is being converted into mechanical energy, and so the sound is absorbed.

Wood paneling and anything else that is lightweight and relatively unrestrained have the same effect. Absorptivity is at its highest at the resonance frequency, usually near or below 100 Hz.


Note Frequency
C = 130.82
C# = 138.59

Close enoungh!

[smeet]

Originally Posted by creis2

I put the gamma pad under the cab.

That's why it didn't work. As others have pointed out, it's a bandaid, but putting the pad under the amp but on top of the cabinet might save your amp from being dumped onto the floor.

But obviously you need to get the cab fixed, and don't get another one until you know the design or build flaw won't recur.

[mcm]

Velcro baby!!!!

[AllenLee]

I wish my speakers were loud enough to vibrate heads off..... jk. This reminds me of a show I played where they had a bass rig anyone could use. Now, when I say bass rig, there's a heavy emphasis on RIG as in this thing was RIGGED!

The amp was a Fender BXR Dual Bass 400 or something with homemade 4x10 and 1x15 cabs. I talked to the guy who set it up who said the head kept vibrating off the cabs, and needed a way to secure it. He called it the Mahnster.



Maybe something like this could be your solution?

[creis2]

I was kind of hoping it was an issue with the duratex.

It's the weirdest thing. I've had heads maybe shift a few mm, but nothing like this.

The weird thing, the head only slides backwards. I gigged with it over the weekend and had to wedge my hardshell case between the wall and the back of my head. It stayed put, didn't go sideways or forwards. It just wants to move back.


I've had all types of issues with cabs over the years. I sold all of my mass produced stuff and had custom stuff made. It never ends.


I know velcro or something will work, but that doesn't solve the problem.

[CL400Peavey]

Sounds like their is a slight slope to the cab. Still shouldn't be vibrating that much though.

[lowphatbass]

Originally Posted by AllenLee

I wish my speakers were loud enough to vibrate heads off..... jk. This reminds me of a show I played where they had a bass rig anyone could use. Now, when I say bass rig, there's a heavy emphasis on RIG as in this thing was RIGGED!

The amp was a Fender BXR Dual Bass 400 or something with homemade 4x10 and 1x15 cabs. I talked to the guy who set it up who said the head kept vibrating off the cabs, and needed a way to secure it. He called it the Mahnster.

Attachment 314284

Maybe something like this could be your solution?

Good Lord!

[Bassmec]

Fore all future solutions a wise man may first regard the past:

If you wimps must keep getting your speaker cabs made out of discarded tea chests.
PS Or you could just man up a bit and plane it back to wood and laminate the exterior box with cascophen glue and 1/4 inch bs 1088 ply.

[PatQ]

Finally! Now there's a solution on transporting heavy gear. Someone call the roadies, they are fired.

[T-Bird]

Hi.

Originally Posted by B-string

It is better to solve the problem (cab) than to treat the symptom. Yes?

Fortunately there's a few posters participating here who do think like that .

When talking about sub 2KW MI/PA drivers/cabs, there just isn't enough mechanical energy to move anything unless the surfaces were totally frictionless.
And even if the "surfaces" are frictionless, for example when flying bass arrays, the cabs don't move much.
If at all.

The cab just flexes, and that causes the vibration (and robs probably half the SPL in the process), not directly the mechanical energy from the driver.

As countless others have said, contact the builder, he definitely wants to find out what causes the flexing. I know I would .



BTW, just out of curiosity: C#?

As C#1 or C#2?
Probably not C#0 with a tube amp though?

Regards
Sam

[username1]

I had the same problem with hi frequency bullets vibrating off the PA cabs. The cabs were a painted finish and slippery. I just put a peice of that thin rubber you would line a tool box or kitchen drawer with on top of the cab and problem solved.

[wcriley]

If the cab is resonating enough to levitate an SVT, drawer liner isn't going to help.

OP: Have you pulled a driver and looked inside the box? Maybe some of the bracing came loose during shipping/transport.

[guy n. cognito]

Subscribed. I just have to see this......

[Timmah]

Sub'd!

[CL400Peavey]

Originally Posted by wcriley

If the cab is resonating enough to levitate an SVT, drawer liner isn't going to help.

OP: Have you pulled a driver and looked inside the box? Maybe some of the bracing came loose during shipping/transport.

+1

The solution to this is inside the cab one way or another.

[MrLenny1]

Ah, physics at work.
It's the duratex at a certain frequency.
Betcha it wouldn't move on rat fur.
That is amazing though, a video of this could go viral,
at least here on TB.