Warped Neck Maybe?

[warfrat73]

I've been having a bit of a problem with intonation on my Bourgeois for, honestly, a couple of years now. The G and B in particular are a couple of cents sharp and have been for a while.

I thought it was the saddle I made for it a few years ago. So then a little over a year ago I bought a saddle from Bob Colosi, but the problem persisted.

I figured maybe the saddle needed tweaking, or maybe when I adjusted the action at the nut I moved the break point back a bit.

I'd kind of just been living with it, and trying to average out the tuning, but leaning more towards playing my other guitars and figured I'd take care of it eventually.

Anyway, to the point.

This morning I finally took it in to one of the two repair people in the area that had been recommended to me. He took a look at it, sighted down the neck and told me I had a slight twist in it. He showed me what he was looking at: sighting down the neck from the headstock and using the string as a straight edge, the bass side has a pretty consistent relief curve. On the treble side, though, it looks like it kind of runs parallel to the string from the nut to about the 6th fret, and then there's a clear curve.

What's the best way to test/measure to quantify this? Just put a straight edge on it?

I shot off an email to Bourgeois about it, but haven't heard back yet (I'm sure I will before too long). If this really is an issue, it should be covered under warranty.

But in the mean time, I'm wanting to assess the situation a bit more.

[John Arnold]

If anything, a twisted neck would affect intonation on one side, not just the G and B strings. That said, a neck would have to have a lot of bow to create noticeable sharp intonation, and it would be restricted to the middle part of the neck, assuming the 12th fret action is reasonable.
Sharp intonation on a B string is not uncommon, particularly with a thin saddle which doesn't allow room for much compensation.
I would concentrate on the nut, making sure the string is stopped at the fingerboard. As you have indicated, a string that is vibrating in the nut slot will tend to intonate sharp.

[charles Tauber]

As John pointed out, the amount of twist/bow in the neck would have to be considerable to alter the intonation. A slight twist is irrelevant to intonation.

How are you determining that the G and B strings play a few cents sharp? Do they play equally sharp at each fret or do they get progressively sharper the higher the fret?

[warfrat73]

It did seem to me that the two things didn't have a whole lot to do with each other. I don't really have a ton of faith in this guy, but his the most highly recommended without driving more than an hour... which is doable, but I was expecting this to be pretty basic stuff.

I'm basing it on using a D'addario clip on tuner, but the guy at the shop confirmed it on the strobe tuner.

Based on the readings it gets a bit worse progressively, but not significantly. Within the resolution of the D'addario, it's about 1/2-1 cent more sharp at the 12th fret as it is on the 1st... that second bar kind of flashes in and out. So basically, at the first fret it's about 1 cent sharp and at 12 it's about 1 1/2-2.
The High e is a bit sharp, but not as much as the B and G.

The other strings are pretty close.

On further reflection, I'm not actually certain that the little bars on the tuner correspond to cents exactly... possibly a flawed assumption.

[redir]

If you hear it then you don't need a tuner to prove it.

Twists like that are very common. It could be that the neck is a piece of reaction wood and in that case there is nothing you can do about it. But it's fairly common to have more relieve on one side of a fretboard over the other and as mentioned it will have nothing to do with the intonation.

Don't lengthen the string at the nut end, you don't want to push that contact point back. The string should exit the nut at the face of the fretboard, unless you want to get into compensating a nut which is a heck of a job. If the string is sharp then you want to move the saddle point back. That's pretty easy to do with a small file.

Is the action high on the guitar? That can cause intonation issues too.

As you are probably aware it's physically impossible to tune a guitar to perfection. It could be that your ear has developed well enough to hear those imperfections and it can drive you crazy. But sometimes it's just something you have to deal with by tuning the guitar up to deal with the discrepancy. You can in most cases at least make it better though and that is usually by intonating the saddle.

[warfrat73]

Originally Posted by redir

Twists like that are very common. It could be that the neck is a piece of reaction wood and in that case there is nothing you can do about it. But it's fairly common to have more relieve on one side of a fretboard over the other and as mentioned it will have nothing to do with the intonation.

Yeah, it really doesn't look that much different than my other instruments, but it's definitely not even on both sides.

It could be that my ear has gotten better, and that I have more points of comparison than I used to. It's really only been a few years that I've regularly played guitars other than this one. And the intonation on my Martins is definitely better at the moment. Maybe it's been like that all along, but when this was the only thing I played, I just thought it was normal.

I've had this guitar for ~21 years, early on in that time, when I was younger, and didn't necessarily have the right tools or know what I was doing, I did lower the action at the nut, and had to expand the nut slot on the G string because it was binding; it was a notably sloppy job.

The action is about where I like it, but I do play bluegrass on the thing, so it's high by some standards. Freshly measured out as follows with feeler gauges:
Action:
Low E .090"
High E .075"

Relief:
Low E .007
High E .002

I'd never measured the relief on the high e before, but I found the difference curious.

Action at the nut is set so that there's just a hint of clearance between the string and the first fret when fretted on the second (except for the G string which actually does touch).

I had called the shop on Wed and really just wanted a new nut put on, and maybe minor tweaks to the saddle. I had been planning on adjusting the saddle a bit myself (not that there's really any where to go with the B string), but just hadn't gotten around to it, and just wanted to give it someone and have it done.

I've actually wanted a new nut on it for a while because of my sloppiness in adjusting previously, and the fact that this particular model came with a plastic nut (Tusq maybe?)... likely the only Bourgeois model ever to do so.

And then I'm on down this rabbit hole. I did tell the guy that I'd get in touch with Bourgeois about it, and that it should be covered under warranty if it's twisted, and he agreed that that was the best option. He wasn't trying to press me into letting him do work on it, though he did suggest that it should be addressed before I worry about the intonation too much more.

I don't know, I don't want to just send it off on a little vacation to Maine so that they can tell me it's fine and not do anything. I'd rather get an opinion from someone I know is competent first... the only person in easy driving distance that I know is competent is Bernie Lehmann... maybe I'll get in touch with him, it's only about an hour drive.

[charles Tauber]

Originally Posted by warfrat73

Based on the readings it gets a bit worse progressively, but not significantly. Within the resolution of the D'addario, it's about 1/2-1 cent more sharp at the 12th fret as it is on the 1st... that second bar kind of flashes in and out. So basically, at the first fret it's about 1 cent sharp and at 12 it's about 1 1/2-2.
The High e is a bit sharp, but not as much as the B and G.

The other strings are pretty close.

On further reflection, I'm not actually certain that the little bars on the tuner correspond to cents exactly... possibly a flawed assumption.

A "good" ear can distinguish between pitches about 2 cents apart. Some people can hear less than that, many no where near that. (There are, or used to be, on-line tests you can take to estimate what you can hear.)

If your guitar has notes that are, as you say, 1-1/2 cents out, chances are, that you can't hear that. Notes whose errors "stack" the wrong way to 3 or so cents are likely audible. Add to that issues due to tuning methods (e.g. mixing equal temperament and just tuning) and playing technique (e.g. playing with a "death grip", etc.) and one can quickly have an out of tune guitar.

It is impossible to get the intonation on a guitar perfect - all notes, zero cents out - but one can get as "arbitrarily close" as one choses. I'm not going to go into the details here, but if you'd like the basics of it can be found here, under the section Intonation: https://www.charlestauber.com/luthie...1-Sept2018.pdf


It is not at all uncommon to have slightly more relief on the bass side than the treble side: I'd argue that there should be more relief on the bass strings, with their larger amplitude of vibration, than on the treble strings - some classical guitars are purposely made that way. It is not an indication of some flaw or a twisted neck and in small amounts will not contribute to intonation problems. I wouldn't give it a second thought.

While I haven't seen your guitar, it brings into question the knowledge of someone who attributes a few thousandths of an inch difference in neck relief as the source of intonation issues.

[John Arnold]

Relief is fine. I would concentrate on the saddle compensation.

[warfrat73]

Yeah, after I posted that it occurred to me that since there's more tension on the bass side it makes sense that the neck would be more deflected there.

Like I said, I had planned on just adjusting the intonation myself at the saddle, but for whatever reason put it off and just decided I wanted to just pay a "professional" and get it done and over with.

I was pretty skeptical going in, but the guy was recommended by a couple people. The best around doesn't necessarily mean a lot if there's no competition.

I'm just going to go do it after I eat lunch.

[nitram]

Does anyone reading this know how common a twist of the neck is, generally speaking? My J-45 has a bit of a twist but it plays fine and the intonation is pretty darn good. Is this a problem looking for a person to worry about it?

[redir]

Originally Posted by nitram

Does anyone reading this know how common a twist of the neck is, generally speaking? My J-45 has a bit of a twist but it plays fine and the intonation is pretty darn good. Is this a problem looking for a person to worry about it?

"it plays fine and the intonation is pretty darn good."

Don't worry about it

[warfrat73]

Well, another one for the "don't put off until tomorrow what you can do today" camp.

About 15 minutes (including removing and replacing the strings) and a bit of 220 and the g and the e are much closer, all take off a bit more next time I change strings. Not much I can do about the b, but that's always the problem child. I think if I make another saddle from scratch I can get it a bit closer by basically leaving the edge flush, but as it is it's a bit rounded over, so I can't really add more compensation without also lowering the action.

I think part of my problem here was expecting the the Colosi saddle would be dead on.

Also, as for the twist...I can see a little something, if I look really closely, but don't feel it, and it doesn't affect playability. So...

[Taylor Ham]

In addition, how are the fret crowns? If there's a noticeable divot in each fret under the b string, that would consistently play sharp as well. The G string is probably just a compensation thing.

[John Arnold]

Does anyone reading this know how common a twist of the neck is, generally speaking?

Very common, particularly on the older guitars I concentrate on. You may think that more relief on the bass side predominates (due to the string tension distribution and lower action on the treble side), but for whatever reason, I see a lot of guitars that have more on the treble side.