Impossible intonation???

[1Drop]

So I've been playing a warwick corvette fna jazzman 5er for 12 years now. About a year ago I switched to flatwounds which required a little custom filing of the bridge saddle for the b string. The stock saddle only seemed to accomodate tapered strings for some reason. So I installed the strings and checked the intonation and not surprisingly I had to adjust pretty much every saddle. All went well till I got to the B string. I took the saddle all the way back to where the tensioner spring was fully compressed. It was still out, so I took the spring out and moved the saddle back as far as far as it would go and its still not quite right. I've checked it with numerous tuners and the all read the same, if my oben B is right on then my fretted E is a tad sharpe and my twelve fret B is that much more sharpe. I don't get it. Am I just screwed or am I missing something? Is it possible that the string is just bad?

TIA!!

[Slowgypsy]

You changed your strings to flatwound a year ago and now you're checking your intonation and finding the B string is off. Is that correct?

If yes, one of the symptoms of a string at the end of its life is the inability to intonate properly. Rounds rarely get to that point 'cause folks usually change them out before then. But flats tend to get left on for ages, and then this intonation problem can occur.

Not 100% sure on this, but it's a good possibility.

[walterw]

Make sure the string is not curving up off the saddle.

Firmly press on either side of the contact point at the bridge, so that the string has a defined bend rather than a curve; while you're at it, do the nut as well, and do the other strings, too.

The idea is for the vibrating part of the string to be dead-straight along its entire vibrating length. Doing so will normalize the intonation, and give you lower action as well.

[1Drop]

Originally Posted by Slowgypsy

You changed your strings to flatwound a year ago and now you're checking your intonation and finding the B string is off. Is that correct?

If yes, one of the symptoms of a string at the end of its life is the inability to intonate properly. Rounds rarely get to that point 'cause folks usually change them out before then. But flats tend to get left on for ages, and then this intonation problem can occur.

Not 100% sure on this, but it's a good possibility.

I checked intonation when I put the strings on. At the time it seemed like it wasn't really noticeable that the B was off a bit. Its more of a mental thing really, every time I tune I see that its off, and its driving me batty even though most ears probably can't hear it. I spend a lot of time on the b, I don't play many open string notes. It seems I get a fatter tone with a fretted E than an open E. I play in a reggae band so the fatter the better.. So I've been tuning it so the fretted E is right on, but I'd like it to be perfect for piece of mind more than anything.

[1Drop]

Originally Posted by walterw

Make sure the string is not curving up off the saddle.

Firmly press on either side of the contact point at the bridge, so that the string has a defined bend rather than a curve; while you're at it, do the nut as well, and do the other strings, too.

The idea is for the vibrating part of the string to be dead-straight along its entire vibrating length. Doing so will normalize the intonation, and give you lower action as well.

Cool, I will try that. Thank You. That actually could be the culprit because since the saddle is so far back, the angle from the tailpiece to the saddle is a bit extreme.

[bassteban]

I get slightly flamed every time I mention this- & as Warwicks seem to be very consistent in build quality(especially, IME, 12+yrs ago), this may not apply- but I had the same issue w/the B on a Fender Jazz 5. I learned from a luthier that shimming the neck pocket- one or two business cards' thickness at the bridge-ward end of the pocket, subtley increasing the neck angle- will also just slightly increase the distance from nut to bridge, in some cases giving you enough added scale length to intonate.

[Turnaround]

Originally Posted by bassteban

I get slightly flamed every time I mention this- & as Warwicks seem to be very consistent in build quality(especially, IME, 12+yrs ago), this may not apply- but I had the same issue w/the B on a Fender Jazz 5. I learned from a luthier that shimming the neck pocket- one or two business cards' thickness at the bridge-ward end of the pocket, subtley increasing the neck angle- will also just slightly increase the distance from nut to bridge, in some cases giving you enough added scale length to intonate.

That is one of the persitent pieces of misinformation that regularly arises. Typically a shim is in the neighborhood of 15 thousandths of an inch. A quick math check tells me the amount of pivot that will put on a 35" scale neck is less that 1/10th of an inch. On a radius of 35" (the neck scale) that works out to less than 1 ten-thousandth of an inch of difference in the length of the string from nut to bridge, or less than .0004%. That's about a 1/300th of a rotation of the intonation screw. Totally insignificant amount.