Sympathetic Resonance behind fretted note is creating an audible buzz on my acoustic - ideas?

guitarfishbay

I've discovered a combination of open string + fretted note on my acoustic where the fretted note resonantes behind towards the nut as a result of the open string being played.

So as far as physics goes - I'm fairly certain there is nothing I can do in this tuning to stop the string wanting to resonate, as clearly it is being excited by the pitch of the open string.  

FWIW it is 10th fret on my low C string resonating behind the fretted note when played in unison with my open F string.  Long term I'm not likely to play this particular piece in this tuning again after recording it but is there any fix for this issue?  Is it something to do with neck relief and nut height?  Or is it just physics + random chance?  

My frets seem fine and I don't have buzz issues with the strings going from fretted towards the bridge.

Any help much appreciated.

WezV

Try a weight on the headstock.  Might be that a small change in the resonant frequency of the whole neck will fix it... of course it could just move it somewhere more annoying.

If you have a clamp you can try with that, although pad the area of contact first - cardboard or something

if it does work then you can try soemthign mroe permenant - a fatfinger headstock clamp, glueing some weights to the back of the headstock, heavier tuners.... or something like that. 

guitarfishbay

Interesting.

I thought the reason it was resonating was the string tension behind the fretted note matched the frequency of the open note.  Like the way you can make an open string resonate if you play the same note on a fretted string.  I haven't considered or even realised that it could be the neck.

sweepy

Might be worth slightly opening up the nut slot, or try some foam between the sting and headstock, this latter method proved successful on some Strats,

guitarfishbay

What would be the theory behind opening up the nut slot? I have files so could do it, but what would be the methodology and goal filing wise? Foam won't help. I don't want any muting on the fretboard side, and already use a fret wrap to kill ringing behind the nut.

WezV

guitarfishbay said:

Interesting.

I thought the reason it was resonating was the string tension behind the fretted note matched the frequency of the open note.  Like the way you can make an open string resonate if you play the same note on a fretted string.  I haven't considered or even realised that it could be the neck.

it could be either or both, but trying to alter the resonant frequency of the neck with a bit of extra weight is by far the easiest thing to try

Corvus

It's like playing slide, you damp behind the slide because the string vibrates. Could try fitting rubber grommets; though it might not look too pretty it's used to stop wolf tones from behind a bridge with a Bigsby.
Could find something more elegant though like a fabric or leather something 'woven' between the strings, must be something that could be used, or made. It doesn't take much to damp the strings, the hardest part is finding something that doesn't look too bad...

Corvus

Found a pic, see nr the Bigs'

http://www.alleykat.co.uk/images/stuff/custom_bigsby_arms/lg_ss_body.jpg 

sweepy

Opening up the nut slots a little can stop the string getting "pinched" if they don't creak or stick, then it's unlikely, but lately I have noticed inconsistencies in string gauges and a little extra room in the slot is not necessarily a bad a idea ,plus make sure the slot isn't flat , and follows a smooth angle similar to the headstock alignment. Flat nut slots on certain instruments can generate very odd noises indeed.

The foam i was alluding to, would be after the nut and under the strings, 

EdGrip

I just put something on the string behind the but to damp it (I use a bit of old pickup wire)

guitarfishbay

I forgot to update this thread -

I checked the neck relief with a feeler gauge and there was very little relief!  The nut slots all seemed fine and the frets are in good condition.  After setting the relief to .010 inches I have no more issues with the buzzing behind the fretted note.  I was pretty glad that something very simple seemed to fix it!