Intonation question (possibly dumb)

[zamzara]

Hi everyone.

I've been puzzling over something recently and I figure someone here is bound to know.

Why is it that the saddle positions for adjusting intonation form a stairstep pattern that is split into two, resetting on the 4th string, rather than a single stairstep going all the way across?

Seeing as the string thickness gets progressively less as you go across, I can't see a reason for it. Sorry for the pointless question but I don't like having to 'just accept' things.

[sumgai]

zammy,

Hi, and to the forums!

Your question isn't dumb, it just hasn't been asked here before. Fortunately, the answer is easy..... Wound strings stretch at a different rate than unwound (plain) strings.

That's the short answer. The long one goes something like this:

When you stop to recall that both ends of a string are locked in place, then how else can a string be pressed down to a fret - it must deform, or stretch. That stretching action translates into more tension on the string, and it doesn't take a rocket scientist to see that greater tension equals higher frequency. We compensate for that increased tension by increasing the length of the string, thus lowering the frequency back down to what we wanted in the first place.

You spoke of the difference between the 3rd and 4th strings. But what you were really pointing out was the break between the plain and wound strings.
[glow=red,2,300]AHA![/glow]Wound strings have smaller diameter cores, hence, they don't stretch nearly as much as would a plain string of the same overall diameter. (The wrap, by it's very nature, doesn't affect the amount of string stretch.) This explains the 'step' in our bridge saddle compensation - less diameter, less stretch, less tension, shorter string compensation. It all falls in line, right?

And for further proof, you need only install a set of heavy gauge strings on your own axe (if it has adjustable saddles). Chances are excellent that if you mount up a wound G string, and re-intonate the guitar, you'll find the 'step' is now between the 2nd and 3rd strings.

It's all smoke and mirrors, so ignore the little man behind the curtain, and all will be well. ;D

HTH


sumgai

[zamzara]

Thanks very much, that makes perfect sense now!