sympathetic vibration?

[theblast]

Have any of you ever had a problem with an acoustic guitar where you strum a certain chord & you get a terrible rattling sound or "vibration" known as a sympathetic vibration? If so, is it fixable?

 

Best

[grampa]

Mine doesn't "rattle" but it is full of all kinds of harmonics that I love.

[Thermionik]

In order to rattle, something has to be (a) loose and ( close enough to something else to rattle against it.

Guitars should not be like that - rattle is not a sound you want.

 

Is it the truss rod - damp the strings and hit the back of the neck - does it rattle?

Is there something loose inside it - damp the strings and shake it - does it rattle?

Is the pickguard loose - damp the strings and tap it - does it rattle?

Are all the machineheads tight - check ALL parts, knobs, pegs, mounting nuts, covers etc;

Strap-lock buttons - all tight?

Go over the entire body tapping - does it rattle someplace, and if so is it internal (strut come unglued) or external (joint come unglued).

High note rattle - look for smaller items / low note rattle, suspect a larger component.

 

Whatever - it should NOT rattle.....

[ballcorner]

Buzz can come from truss rod being too loose, a tuning peg that is not attached properly or has a ferrule that isn't tight. You can get a buzz from a fret that is high, a nut slot that is too wide and any number of other things.

 

One thing is certain: Have your guitar looked at by a technician as soon as you can - that will almost surely fix the problem and get you back on the road to happy, buzz free playing.

[Thermionik]

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To clarify, theblast - is it a rattle (as OP said) or a buzz (as ballcorner said).

 

Whole different symptom - whole different causes.....

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[theblast]

I had a very well know tech look at it & he determined in about 10 seconds that this is a "Sympathetic Vibration". Here's the scenario:

 

1. capo on 1st fret

2. strum chord

3. horrible rattle starts

4. when he placed his finger just lightly on the strings below where I fretted them, the rattle / vibration stopped.

 

He said it's not fixable & it's very rare. I'd have to deal with the store I bought the guitar from about 3 months ago. They had no clue what it was so now I'm going to have to send it back to Gibson. If I'd have known that this guitar had this "Rare" issue, I wouldn't have purchased it. I really hope Gibson does right by this. The store I bought it from wouldn't even pay the shipping charges for me to return it to Gibson. I'm really hoping this works out but I'm sort of nervous.

[nid2007]

I had it on my j-45. Was like a cricket in my guitar. One trip to the luthier and it was gone. Took 5 minutes.

[zeebee]

Try and isolate the source of the Buzz/rattle........my son's Larrivee had one a month back. We determined it was coming from the neck block area. It therefore had to be the truss rod nut. Guess what ...it was.

[Thermionik]

Well, theblast, this 'HORRIBLE RATTLE' (not just a little BUZZ then.....), if the very well known techncian determined within 10 seconds that it was a "Sympathetic Vibration", then I must be a very well known technician too - and I ain't.

 

All the expression "Sympathetic Vibration" means is a vibration induced in a second object by a vibration in the first object, and almost invariably it happens at either the fundamental frequency or a harmonic of the vibration of the first object.

 

What happend was like taking your car to the garage and telling them there was a strange noise coming from it. Within 10 seconds the mechanic says 'that's what we call a "knocking sound" - there is no cure'. Sorry to disrespect that mechanic, but it could be a big-end gone loose, might be a bit of suspension knocking against something, possibly an engine mount come adrift. One thing it 100% definately is NOT is 'not fixable'.

 

Here's the thing. It happens when:

 

(1) you capo on the 1st fret and play a chord.

 

(2) a finger lightly placed on the strings below your fretted chord stops the rattle.

 

From (1) is it EVERY chord or just SOME chords. Can you isolate one string in the chord that makes the rattle. And here's a thought - does it happen at all WITHOUT the capo in place, like if you barre-chord instead.

 

From (2) Try the same thing, but have him hold the headstock instead of the strings, then the back of the neck instead of the strings (we are looking to see if it's the truss-rod or machine heads here.....). When you say he placed one finger lightly below your fretted chord - is it the string between your fingers and the capo (too much neck relief perhaps, or a loose fretwire).

 

I don't wish to disrespect your tech - but it IS fixable, and a little more time WILL nail the fault to a specific item. Don't give up - I suggest a 'Second Opinion'.....

[albertjohn]

When it comes to technical matters, I'm no expert at all. However, I would agree with Nik that just about everything is fixable. The chap I use is top class.

 

However, don't forget there may be warranty issues here so take care with it.

 

I hope you get it fixed soon.

[RogueBrit]

Another possible cause of the type of rattle you describe is a 'back-rattle' of the strings aginst frets behind where they are being fretted. The experiment with the capo could support this diagnosis. it is caused, generally and if the fret job is basically OK, by TOO LITTLE neck relief. Go and have a look at Frank ford's FRETS site where this is discussed in detail. It can cause really 'head-scratching' effects that are a real puzzle unless you know. I have seen situations where there is a rattle on an entirely different string to that being struck. It needs to be looked at by someone who knows their business - if you do not have the experience yourself - to avoid a costly and possibly wrong diagnosis IMHO. Before resorting to brace and other fundamental work, I would therefore recommend getting several opinions.

 

Roger

[RogueBrit]

Oh - and I agree with Thermionik - I have not yet seen a problem of this sort - whatever the cause - that was not fixable, and usually easily.

[TommyK]

If placing a finger lightly on a string stops the rattle, it's fret buzz. Have the frets checked for level, have the neck checked for flatness. Too, the nut may be worn or cut too deeply. A set-up may be inorder.

 

If the area he touched was between the capo and the first fret, I'd venture to say the capo wasn't properly installed or.. the capo isn't up to the task, or doesn't work with your neck. I bought one of those $1.99 Dunlop rubber band capos and had a fit making it work. Then I realized this type of capo is best suited for flat fretboards, as the hardened pin running through the center of the rubber spool is dead nuts flat. It is not designed for a radiused fretboard. I broke down and bought a $12.00 Kysor. It's designed for radiused boards.

 

"Can't be fixed?" Don't let that guy touch your guit tars ever again.

[theblast]

Wow, thanks for all the info guys. I really appreciate it.

 

This vibration seems to only happen when I play a G# (6th fret on E string) & a D (5th fret on A string) & a few other combinations in that area. The loud buzzing / vibration SOUNDS like the truss rod is vibrating. However, when I lightly touch the low E string below where I'm freting, the noise stops. I guess the nut slot could be too deep, allowing the low E string to vibrate against a fret.

 

The thing that sucks is that the store I bought it from had their tech look at it, check the truss rod & couldn't figure out the problem. I immediately went to the authorized repair guy here in LA & he gave me the whole "Sypathetic Vibration" thing. Now it seems to be a warantee issue which means not only do I have to ship the guitar back to Gibson but on my own dime as well. LAME!!!!!!!!!!!

 

Is it possible that the Authorized repair guy is soooo busy that it wasn't worth his time to want to fix it & it was easier to just have me leave with it & have Gibson deal with it?

[jefleppard]

in the long run, its much better to ship it back than have to either live with it or drive it around from tech to tech in some sort of keystone cops type of sequence, imo.

[albertjohn]

in the long run' date=' its much better to ship it back than have to either live with it or drive it around from tech to tech in some sort of keystone cops type of sequence, imo. [/quote']

 

+1 on this. I know it's a pain and not without expense, but I'd be concerned about invalidating the warranty. I'm sure they're all really great blokes in Bozeman (not meant to be sarcastic) but an invalidated warranty is exactly that. So returning it to Gibson would be top of my list.

 

Will Gibson not refund the carraige in these situations?