Double Bass Buzzing bass bar?

[Thomas Stone]

What does a loose bass bar sound like?
I know, i know, how long is a bit of string?

Have no fear I'm not expecting a web diagnosis.

I Just got my bass ready for some recording today, pizzed an open e and there was a whole lot of vibrating going on somewhere. Not noticeable on the attack of the string but it is loud as the string decays then the buzzing stops once the note gets below a certain volume

some good loud open string arco gave an even worse result. the buzz is noticeable against the note as it is being drawn.

I ran a playing card (buss pass for london, uk TBers) around the seams and no gaps were found. I did a search here on "buzzing" and from those results checked the saddle, talpiece, bridge adjusters, strings, you name it. I'm almost certain the buzzing is coming from inside the body.

This might be related to a funny buzz i've had going on for a few weeks, which was generated by "twanging" the fingerboard, like a diving board. That was a much quiter buzz which seemed to coming from the left hand shoulder (as the bass faces you) although it may have been more central. I'd always assumed this was a loose rib. it was more of an annoyance rather than a problem.

This new very loud buzz seems to be coming from the bridge area on the left hand side of the bass.
This could be my paranoia convincing me that the buzzing is in the region of the bass bar. I'm hoping that it is simply (?) a loose rib or brace, although a loose back brace seems just as bad to my mind.


The recording will have to be postponed and i'll get the bass in to my luthier asap, but in the meantime i'd be very grateful if anyone who has suffered a loosening bass bar could describe the sounds coming from their bass as the problem worsened.


guess that mark bass little-mark amp will have to wait.

thanks in advance
thomas

 

[Deltree]

No idea what a loose bass bar sounds like, but if not that, might it be the length of endpin thats inside your bass? I've just had a new endpin fitted and found that it would buzz if it wasn't quite secure. The same thing led me to cut my last one down FWIW

 

[Thomas Stone]

Thats a good idea tomasito, but It had already crossed my mind too and i've been playing the bass as a test wth the endpin fully removed.

Buzzing continues.

We'll see what the luthier has to say, although i have to wait and cross my fingers for a week before i can get time to get it to him.

 

[Uncletoad]

Is there a pickup on it? My output jack rattles around sometimes.

 

[Tbeers]

Is the sound metallic? That's always the first question I ask. Metallic buzzing is GOOD haha. That means it's easy and cheap to fix.

 

[prelims222]

Hi Thomas,

Is your bass flat or round backed? I ask because I've had a lot of experiences with back braces coming loose and creating a 'mystery' buzz.

 

[Thomas Stone]

Thanks all,

I don't have a pickup attached (when i do though it capable of making some great rattles though)

Hhmmm A metalic buzz, It does sound like a spring i suppose.

My bass is a flat back. I had worried it might be a back brace, but i can't work out if the buzzing is coming from the table or the back.

When i knock all over the body i can't seem to generate the buzz. It comes from the string resonance.

Thanks again for the ideas.

 

[vier-personen]

I have a similiar problem with my roundback.
There is a buzz sound that is noticable in the middle of a tone, the attack is clean, then it buzzes, then the buzz stops as the tone fades, like you described your sound.
Sometimes this buzz is so loud, that I really get angry, sometimes there is no buzz at all, I guess this has to do with humidity. It can be really annoying.
I was at my luthier a year ago to find the part that is causing the buzz, and after 1 hour of searching we gave up. The buzz can be stopped by damping the top, but there was no way to find out where the buzz was coming from.
I guess I´ll have to let my luthier open the bass and do some major work, redo all the bad repairs that where done before I got the bass.
That´s my story, anyway.

 

[360guy]

Here are some things I would try.

Does the buzz appear whenever you create a specific tone (frequency) regardless of which string you play?

If not is it only on one string? Switch the string to a different position temporarily ie. put the 4th string in the 3rd string position. tune it up and play the tone again. If it stops buzzing it could indicate that location (perhaps to the bass bar ) has something to do with it.

Also you could do the machanics trick: use a piece of tubing or hose held between the ear and the bass. Create the buzz while another person probes the end of the hose around to locate the buzz.

As a repairman I would have the bass on the bench and use a mirror and light to check it viually very quickly.

I hope this helps.

 

[arnoldschnitzer]

Check that the soundpost fits well UNDER TENSION. Basses with flexible tops often distort when the post is tightened. Then there's a small gap between the top and soundpost which can cause a buzz. A chip in the post can also rattle (more common than you'd think).

 

[Thomas Stone]

The rubber tubing is a good idea.

I've been searching high and low for an old doctors stethascope i used to own to try and listen in on the buzz, but the tubing trick would allow greater internal access.

The buzzing doesn't seem to be tone dependant, but it is more noticeable on the lower pitched strings as presumably they have more energy in their vibration...?

I'll get my luthier to check the soundpost fit next week, thats a good suggestion and one i never would have thought of. Thanks

I'll keep you posted

thomas