Strange micro-harmonics on single notes

[Kevin Winn]

I have an Eastman MD 315, and recently changed to light gauge strings. I am noticing that when I play a G note on the E course (3rd fret), I am getting a ringing micro-harmonic from the D strings. Same for a C note on the A course (harmonics coming from the G strings). They are not particularly pleasant. I don't recall this happening before I changed string gauge, but it is possible.

Cause(s)? Remedies?

And I do have a dampening foam strip under the strings in the tailpiece.

[Ray(T)]

Foam? Change it to felt and try adding one to the strings between the nut and tuners.

[jshane]

Interesting that the harmonic is the same chromatic distance from the sounded note in each example (a 5th up, or 4th down depending on your point of view).

Just wondering aloud here, but is it possible that the lighter strings are accentuating an overtone that was not as strong in the other strings, which in turn is sympathetically vibrating the open strings?

Do you have the old strings to replace temporarily as a test?

[OldSausage]

Have a good close look at your nut slots.

[pit lenz]

The way you describe it, the resonance seems to come from the main part of the strings, not the part behind the bridge, right?
If so, another piece of felt or foam at the tailpiece wouldn‘t make too big of a difference.
It is quite natural that undamped (open) strings resonate not only if agitated by playing other strings in their own frequency but also in the frequencies of their overtones (mainly octave, fifth and fourth).
Maybe, as jshane stated above, the lighter string selection tends to react more easily to that...

[Kevin Winn]

Yes, the resonance is coming from the main section of the strings. When I play a G on the E strings and quickly pull off, like a staccato note, it leaves only the resonating harmonic, which stops when I touch the D strings. It's very weird. I haven't been able to find any other notes that cause the ringing, just those two. Unfortunate, as they are used a lot...

I would think that the sympathetic resonance would be part of the harmonics of the original note. These are very dissonant.

Thanks for the responses. I may take this issue to the Builders forum. Those guys may have some more insights.

- - - Updated - - -

Have a good close look at your nut slots.

And what should I be looking for?

[Givson]

Dampen the strings above the nut.

[OldSausage]

Yes, the resonance is coming from the main section of the strings. When I play a G on the E strings and quickly pull off, like a staccato note, it leaves only the resonating harmonic, which stops when I touch the D strings. It's very weird. I haven't been able to find any other notes that cause the ringing, just those two. Unfortunate, as they are used a lot...

I would think that the sympathetic resonance would be part of the harmonics of the original note. These are very dissonant.

Thanks for the responses. I may take this issue to the Builders forum. Those guys may have some more insights.

- - - Updated - - -



And what should I be looking for?

Strings not fitting snugly in the slots, slots uneven, that sort of thing.

[pops1]

It is possible that the lighter string are able to sympathetically vibrate easier than heavier strings. I would try your original gauge and see if it is still happening.

[Kevin Winn]

Dampen the strings above the nut.

That didn't make any difference.

[Kevin Winn]

Here's a link to a YouTube video. I play a G four times. You can hear the ringing pretty clearly. The first two times, I let it ring. The second two times I reach up and deaden the D strings, which kills the ringing.

https://www.youtube.com/watch?v=u5dDb8q3MUg

[HoGo]

The lighter strings react to resonance of body easier. Your mandolin is probably lightly built and responsive which is IMO good.
I believe you'll findi this in other mandolins to some degree as well.

[Willie Poole]

I got a good deal on buying a mandolin when the original owner said he didn`t like the tone of the instrument and it came with light gauge strings on it and after changing to the medium gauge I didn`t see anything wrong with the sound of it...I would go back to the medium strings if it were up to me...your mandolin will handle mediums without any problems, but getting a good set up wouldn`t hurt at all either...

Willie