Sustain dying out

[Styrr]

Not sure if anyone can answer this but here goes.
Problem – sustain dying out on B string fretted at 12th fret.  i.e an octave above natural B. It also happens playing at the 13th fret  [C].
Also happens with G string at 12th fret, but to a lesser extent.
Doesn’t happen with any other string or those strings at any open or fretted positions.
Tried it on all my guitars (electric) and it varies on most to some extent. It is most noticeable on 2 of my guitars that sustain the most. That may be because they normally ring forever  which makes it more noticeable. Seems that those with trems are less of a problem.  On my Strat there is hardly any difference, it is there but only because I am listening for it.
My guitars are quite a mixture from hard tails to trems and even a bigsby, and different string gauges and manufacturers. 9-42s, 9-46s, 10-46s and 11-49s.

It isn’t a high fret(s) issue and I don’t think it’s a pick up height issue either (as it happens no matter which pick up combination I use).. All guitars are set up to factory specs, so they are not set up for low action. Intonation pretty good too.

Done quite a lot of research and not come up with a reason or solution. Could it be just that those frequencies don’t quite line up for the nodes ( fret to saddle) ?. I would have thought that intonation would have sorted that. And it doesn’t happen with the high E at 7th fret.
Only noticed this because I was learning the guitar solo for Mark Knopfler’s  Wild theme/ Local Hero. Now I wish I hadn’t entered this particular rabbit hole.

Anyone offer any thoughts ? or at least a rabbit hole extraction machine?

Take Care
Styrr

[Dan Graves]

Have someone check the setup, I can't replicate this issue on either my Les Paul, my PRS C24 or my Annihilator (hardtail, floating trem and floyd rose respectively).
The topnut and bridge would be my first places to check, then neck curvature and intonation.

I'd also like to point out that 'factory spec' setups tend to be mostly uniform, and relatively high, because they're meant to be a fairly safe 'middle ground' sort of thing.
If you'd want them low, (learn to) set them up yourself, or have someone else do it.

[Styrr]

Thanks for the reply Dan,
I know you are pointing out the usual suspects; so here is my thought process:-
Nut and saddles are Ok – besides if there was a problem with the nut; fretting at the 12th fret would surely have eliminated that?. And as the sustain is good on the open string that should indicate that the saddles isn’t the issue either ?
Intonation is good (or as good as it can be depending on the saddle type)

Yes that’s why I said the guitars were set up to factory specs; to make sure that sure that too low an action wasn’t the problem. I didn’t have any fret buzz or choking etc when bending with the action slightly lower as I like it. From all my research that choking on the bends is normally due to a high frets (not that the bending was my problem). I checked with a fret rocker and no the frets are fine too.
 I actually don’t mind the action being a little high and set them up myself. I will lower them a touch if and when I find a solution.
Neck relief is about 10 tho on all of the guitars, so should be good.

It happens to some extent on all 8 of my electric guitars, just some worse than others.
The 3 that is most noticeable are: a PRS Pauls guitar; a Gretsch G5422T hollow body; and a Gibson SG. Then comes the Gibson Les Paul; and a Fender Tele. Least noticeable are on the trem guitars: Fender Strat; PRs custom 24 and a James Tyler JTV69 (Line 6 Variax).

As a measure of how much sustain I am losing I did some timing on the PRS.
On a clean channel, with a minimal amount of gain but the Volume full on and the master set about half way (but attenuated down):-
Open B string; full sustain for about 5 secs, gradually reducing down until about 15 secs.
B string fretted at the 12th Fret; full sustain for about 3 secs; quickly reducing down to 6 max.

I did take one of my guitars in to get it checked out and to confirm I wasn’t just imagining it. Two people played it and confirmed that yes the sustain was dying out quicker when fretted and couldn’t find anything wrong with the set up. The only suggestions were to a) try adjusting the pickup heights and b) if it was still under warranty to take it back to the store I bought it to see what they could do. As it’s a PRS Pauls guitar , it has a limited lifetime warranty – i.e. it’s under warranty as long as the original owner has it. Which is me. That may or may not get the PRS sorted, but won’t do much for the others unless I know what was done.

[Dan Graves]

Well, sometimes life is stranger than fiction; I've handled guitars that would not properly fret or intonate higher up, and the nut was usually the culprit, be it that the groove was either too shallow or too deep, sometimes too narrow.
The reason I mentioned factory spec being middle of the road is because it could also be it's slightly too high for what your guitar can handle.
It would be odd that it would kill sustain that far up, but like I said, life can be stranger than fiction.

But in any case, since it's a PRS, I'd have the store take a look, if it's a deep(er) issue the warranty will cover it, if not, they can fix it for you.
They can be a bit finnicky to get right sometimes ...
I can tell you I've struggled with my SE's at times.

[simon3142]

A slightly off the wall suggestion, If it is problem exists on several guitars, were you always using the same amp/speaker?
Is it possible the the effect is being created after the signal has left the guitar?

[Dan Graves]

It would take a rather weird constellation of faults, or some weird mix of effects pedals and compression/filtering...
Certainly worth a try, should be less effort than having the guitar checked at the store.

[Styrr]

Not necessarily too much of the wall. Something I didn’t consider and an interesting point to test anyway.
So we tried.
Into 2 other different amps, so a tube amp; modelling amp; solid state amp. All combos with different speakers; different speaker sizes; clean channels; and no /pedals/effects  -  essentially the same result. Timings on the normal sustain length varied a little. Interestingly the cut off was the same at 3 secs. So we can probably assume that it is the guitar(s) ?? just to make sure; I did try different cables, various lengths and manufacturers (Cable guys; FenderCustom Shop; and Planet Waves).

Whilst I was doing this testing, I thought I’d try to eliminate the nut issue so I detuned the B string to A. Fretted at the 12th the sustain wasn’t as long as the open string; but no way near as dramatic i.e instead of 3-6 secs it lasted for about 11 secs. So, significantly better.
Which leads me back to the frequencies (and nodal points). To test that; I tried fretting the high E string at the 7th fret. Contrary to my original statement that it was fine; it wasn’t. It wasn’t quite as bad at about 5-7 secs.
Frequency of open B string is approx 494 hertz, fretted (so an octave higher) it is approx 988hz. Beginning to make me think that some guitars might just have a dead(ish) frequency range for resonance.

As an aside; yesterday I took the guitar into another shop where I have bought a number of guitars and equipment and frequently visit when passing. He tried it unplugged and we could hear a buzz at that frequency (and only at that frequency). He thought it was a truss rod that was slightly loose as he had had that before and it wasn’t fret buzz etc. Funny thing is I can’t make it happen at all. I can only get a twang as it hits the frets if I pluck very hard.

So looks like it’s back to the place I bought it to see what they (or PRS) can do. That won’t be this week as it’s holidays and we have grandkids to look after.
Take care all
Styrr

[Dan Graves]

Ye gods, you went into these calculations so deeply we've almost left the land of setups and waltzed into the world of mathematics and algebra 
Respect for being so unbelievably thorough though, you've pretty much eliminated all of the usual suspects.
Do keep us posted, because I'd genuinly like to know how they'll solve it.

[Styrr]

Ye gods, you went into these calculations so deeply we've almost left the land of setups and waltzed into the world of mathematics and algebra 
Respect for being so unbelievably thorough though, you've pretty much eliminated all of the usual suspects.
Do keep us posted, because I'd genuinly like to know how they'll solve it.

Not surprising really. Background of Electrical and electronic engineering; plus 20 years  of software engineering. Degree in maths/physics /computing along with a lifetime career in resolution of problems.
All of this taught me to beware of making assumptions and to try and get to the core of the problem.

Which leads me on to my research assumption failure. Of course I tried with “sustain dying out”. This just led me mainly to problems of choking out on bending. When I tried a different approach :- dead notes it seems that I am not alone in having this problem and one of the solutions is a loose truss rod (another is a fret not seated fully).

 https://www.youtube.com/watch?v=k--sLkeqIM4

Not sure I am convinced that those solutions are reasonable and viable. And to be honest not even going to try sticking fishing weights on the B string. Even if it fixed the issue it’s not a long term solution on a £3000+ guitar.

A loose truss rod is about the only thing I could try (giving that it was also pointed to by a friendly guitar shop owner). I rechecked the neck relief (always do the carpenters maxim – check twice, cut once). It was 12 thou not 10 as it was when I bought it (it’s one of the first things I do when I get a guitar home). I could adjust it and that ‘may’  tighten the truss rod. It’s not a difficult thing to do; but I am now at the stage that bo*;^!ks, let’s see what the PRS dealer comes up with. I will try and go to see them sooner than next week. Will certainly let you know how it turns out.
Take care
Styrr