Neck is all kinds of messed up.

[Muaguana]

My Squier VM fretless jazz has had a buzzing issue going on for a while - notes are choked above the 12th fret only, on all strings but the G despite it having the lowest action. I look down the neck with my right eye parallel to the treble side of the fingerboard (relevant detail) and see the neck is bowed. So I do the rational thing and make small adjustments to the truss rod to straighten it out every couple of days. Still, it persisted.

Yesterday I looked down the neck from the bass side for once and saw the neck was straight as an arrow. The treble side still exhibited a bow. Looking down from the center, I can actually see the treble side of the fingerboard bowing slightly around the 8th fret or so.

Now for the no-brainer question: Does this mean the neck is warped? I thought it was strange how when I set the intonation, the bridge saddle for the A was backed up several millimeters behind the other saddles, which were practically in a straight line.

And the more important question, in case I get a new neck: could this problem have been caused by the fact that, when I first put flats on, I didn't run the D string under the string tree when I cut the length and wound it up? Might that have caused a change in string tension that slowly warped the neck over time?

Thank you for your time and patience.

[202dy]

Diagnosing neck problems over the internet is difficult. Data is important. There is not enough information here to make a guess.

Please measure the string height at the twelfth and last fret on both the bass and treble sides of the neck. These measurements are taken from the top of the top of the fret to the bottom of the string in sixty fourths of an inch or millimeters. Then measure the relief at the seventh fret. Use a straight edge or capo the strings at the first fret and push the string down at the last fret. This measurement is best made with feeler gauges, in thousandths of an inch.

Post the findings here and someone will help you.

[Deathblade Eric]

From what you say it does sound as though there's some inconsistency in the neck - is it a factory fretless or a de-fret? Fingerboard variations are likely to be more common on defrets IMO.

When I defretted my Aria SB-1000 I had a similar issue with notes choking in the upper registers, & tried pretty much what you've done. The eventual cure was to take it to a good luthier & get them to "shoot" the fingerboard in - i.e. sand it true with a radius block. GB£60 later & it sang - turned out that it had a very slight 'S' hump above the 12th fretline that couldn't be seen by eye. Fretlesses are much more susceptible to very minor variations in the neck than their fretted kinfolk.

Regarding the two other issues you raise:

• No, you won't put a twist/warp in the neck by forgetting to run the D under the tree. I regularly tune my G up to A to get an open chord effect with no ill effects (a band I sub for does an Elmore James number & the guitarist doesn't play slide, so my playing a sort of rhythm slide bass helps get the mood a little).
• The errant A saddle could indicate a fingerboard that's out of whack, but it could also be down to the string itself. Not all strings intonate neatly.

Pete.

[Fajah]

Based on your description, it sounds like your neck has a torsional twist to some degree combined with the action being set too low. Here's an extreme example of what happened to my friend's SX STL-50 guitar:

My STL with a straight neck:



His with a torsional twist:



The two pics above are with the neck perfectly straight. When there was some relief added to my friend's neck, one side would look flat and other bowed.

Although I could get his guitar set up so that it was somewhat playable, I eventually changed the neck for him. However, I've set up inexpensive basses where there was a slight twist and they wound up playing pretty good, so it really depends on what degree of a twist you're dealing with.

Originally Posted by Muaguana

notes are choked above the 12th fret only, on all strings but the G despite it having the lowest action.

Generally speaking and IME, any issues dealing with buzzing (and/or lack of a clear sound) above the 12th are fixed by raising the action and not the trussrod. If you had a problem from the 1-5th frets, then a trussrod adjustment is warranted and this is where it becomes tricky with a twisted neck.

So IMO, you have 3 options;

1) Raise the action (assuming that the trussrod is adjusted properly).

2) Because it's a fretless bass, you could sand down the fretboard to compensate.

3) Replace the neck.

Hope this helps.

[Muaguana]

Sorry about the delay, but Thursday is my crazy busy day so I couldn't get the measurements until now (had to re-do them about a thousand times because I kept second-guessing myself - curse you, OCD!)

Action at 12th fret:
G: 2.98mm
E. 2.75mm
" " last fret:
G: 2.71mm
E: 2.61mm

Relief at 7th fret:
G: .075"
E: .054"

To answer Eric's question, it's a factory fretless - ebonol fingerboard (cue boos and groans.)

Originally Posted by Deathblade Eric

Regarding the two other issues you raise:

• No, you won't put a twist/warp in the neck by forgetting to run the D under the tree. I regularly tune my G up to A to get an open chord effect with no ill effects (a band I sub for does an Elmore James number & the guitarist doesn't play slide, so my playing a sort of rhythm slide bass helps get the mood a little).
• The errant A saddle could indicate a fingerboard that's out of whack, but it could also be down to the string itself. Not all strings intonate neatly.

That eliminates one variable; thanks. Maybe I'm getting more weirded out than I should over that A string, but it is a rather odd saddle configuration, especially since when I got the bass it looked pretty much like any other - E furthest back, A more forward, D more forward than A, G out in front. I did a pickup swap at one point, and after that the intonation changed and the buzzing started.

Originally Posted by Fajah

The two pics above are with the neck perfectly straight. When there was some relief added to my friend's neck, one side would look flat and other bowed.

The second picture looks pretty close to my bass, just with concave spots in different locations.

1) Raise the action (assuming that the trussrod is adjusted properly).

2) Because it's a fretless bass, you could sand down the fretboard to compensate.

3) Replace the neck.

Hope this helps.

Indeed it does; thank you for your insight. Although I have tried before, I'll have another go at raising the action. From what I've read, sanding an ebonol fretboard and making it look decent is difficult. I've already started eyeing the classifieds section in case I can't solve the problem or discover the truss rod is boned - I would replace it in a heartbeat if I wasn't broke as hell.

Thanks again for everyone's input so far.