non resonant note

**GTison** · Mar-06-2021, 10:48am

So, I was playing in C, and when playing a C on the E string. It is noticeably less resonant than the notes leading up to that note. It has the fundamental, but the overtones reduce greatly. Is this a "dead fret" or a body resonance difference? What would be the test for a dead fret? Any test for a resonance difference?

**pops1** · Mar-06-2021, 11:34am

Is it seated well, does it move? See if you can use a dowel or something under a good light and push on it to see if it moves. You could also use a thin feeler gauge to see that it is seated, try to slide it under the fret. It might just need a tap, or maybe it needs to be glued in if a tap won't keep it down.

**Nevin** · Mar-06-2021, 11:48am

Good suggestions from pops1. They should help you check the fret. If it is an issue of the mandolin body response you should check the C on the D string. Being the same pitch, if it is the body it should have the same lack of overtones.

**JeffLearman** · Mar-06-2021, 1:28pm

If the notes a half-step above and below sound fine, try retuning to a half- or whole-step low, and see if the problem follows the location or the frequency. That is, if the issue occurs on the same fret, then it's more likely to be related to the location on the instrument (e.g., the fret, fretboard, neck.) If the issue still occurs on a concert C note (a fret or two higher) then it's more likely to be a resonance issue. Siminoff talks about "wolf howls" in his book, and what you're talking about sounds a bit like this. I have a similar problem with Ab on the A string on a classical guitar. The funny thing is, I was going to do this test on it but ... the problem has disappeared. I suspect it'll come back with different humidity.

**GTison** · Mar-06-2021, 2:58pm

Jeff, I like this approach.

**HoGo** · Mar-07-2021, 10:45am

There can be a bad spot on the string, kink or rust...
Wolf notes are almost exclusive to bowed nstrument. I'd bet it's fret or setup.

**Richard500** · Mar-07-2021, 11:25am

Interesting - at least on the physics side. A bowed instrument ‘wolf’ is noticeable because it’s sustained long enough to hear the howling beat tones, and the cure is an added mass damper on the string that is adjusted to prevent it. However, a resonance that ‘robs’ a note of energy can appear on a percussion instrument providing there’s enough time to build up the unwanted vibration. A high note, like that C could have interactions with fairly small structures, like the strings beyond the bridge, so Jeff’s analytic should help sort that out. When I say ‘robs’ what I mean is that a despite the tone getting louder, the harmonic content may be deemphasized.
On the lab table, I guess that you could sweep a transducer frequency at the bridge and find all sorts of effects. The lab is closed, so don’t ask!