Fluke intonation issues solved!

I love my concert surf fluke. I have been using Low G Worth strings ever since I bought it last year; I started on the Browns and gradually worked up to the Clear Mediums. I have been playing Ukulele full time for about a year now and am starting to play more upwards on the neck. I noticed some 4th string intonation issues at the 5th fret (5 cents off) but very pronounced at the 12th (20 cents off).

I went to my local guitar store and purchased a set of Aquila concert strings (AQC's). I wanted a low G, so the music guy sold me a D'addario D (.030") string.

Long story short, my fluke now plays with almost perfect intonation. Maybe 2 cents sharp, if that, at 12th fret. Barely noticeable to my ear.

As much as I love the buttery sound of the Worths, I am going to try to stay with a lighter gauge to maintain my intonation. The sound of the Aquila's are much stronger and brighter than the Worths, but I am liking it.

I can see how a heavier gauge of string could be easier to play w/o inadvertently bending the string and affecting intonation, but not a change in intonation due to different brands of a similar gauge. I've also experienced intonation issues from old strings, but that's another issue.

Can anyone explain why the intonation accuracy would be affected by the brand of string?

I think it has to do with material of the strings and tension they create. The Worth mediums clear are fluorocarbon at .0358" for low G.

I don't have the gauge for the Aquilas, but they appear to be 10-20% lighter, dimensionally. Plus they are a different material. I think these are the true gut string (AQC), based on the price I paid.

The true test would be to measure the actual string tension of both sets. With enough added tension of a heavier string, you will raise the action and shorten the scale a tiny bit (bow the neck). You will have to press the string down more to contact the fret, stretching the string even tighter, resulting in a more 'sharped' tone which is most pronounced at the 12th fret.

Some guitars compensate for this with tension bars in the neck and adjustable compensation at the bridge. I have considered making a compensated saddle for my other uke, but I will try swapping strings first.

Its strange how we hear things differently - I dont like Aquilas on my Fluke Concert and adore Worth Clears!

Are you using low G or reentrant? How is your intonation? I would love to switch back, but the G string on mine goes nickel sharp at the fifth fret; hard to tune.

Ingrate said:- "Can anyone explain why the intonation accuracy would be affected by the brand of string? "

It isn't just the BRAND of string - it can be the individual string itself. You could get a set of (say) Worths that don't sound right on a particular uke; change them for similar set of Worths, and the uke could sing. It applies to all brands.

Modern strings are made to very fine tolerances, but tiny variations in materials and dimensions can make an audible difference. I once had a string that was very slightly thicker at one end than the other. I could just discern the difference using digital calipers. It played havoc with the intonation of my uke.

Ingrate said:

Can anyone explain why the intonation accuracy would be affected by the brand of string?

Click to expand...

It actually varies with the tension on the string. Theoretically, with an uncompensated bridge perfectly perpendicular to the strings, the intonation would be exactly equal on all strings if they were all under exactly the same tension. They never are, and we don't necessarily even want them to be (typically the lighter strings are under a little more tension to equalize volume).

John