Why do guitars need intonation?

[Plessure]

Why do guitar strings need slight differences in scale length with no consistent pattern to the variation? Is it because of slight quality variations or damage in the strings? Or is it because the frets are imperfect?

If it was about the action, there would be a pattern right?

Is it the wood in the neck twisting slightly?

Why do strings not need slightly different fret spacings aswell? As would be the case with a deliberately multiscale instrument.

 

[Darg1911]

Re: Why do guitars need intonation?

It's because of variations in the nationalities of the little fairies that reside in the pores of the fretboard.

 

[Chistopher]

Re: Why do guitars need intonation?

Look up "Microtonal guitar" that'll show you what a truly intonated guitar looks like. A lot of intonation has to do with the thickness of the strings and the required string length to line the notes up with the frets. The exact science, I do not know.

 

[AustinBurrell]

Re: Why do guitars need intonation?

Science. Not a scientist so I can't explain it. But, science.

 

[PS412]

Re: Why do guitars need intonation?

Intonation beats, in most cases, detonation

 

[Plessure]

Re: Why do guitars need intonation?

Look up "Microtonal guitar" that'll show you what a truly intonated guitar looks like. A lot of intonation has to do with the thickness of the strings and the required string length to line the notes up with the frets. The exact science, I do not know.

I already know about microtonal guitars and equal temperament vs just intonation.

If it was the thickness, there would be a pattern.

 

[Demanic]

Re: Why do guitars need intonation?

It's not just the thickness. Different metals and construction methods have different densities, and crystaline structure at the molecular level. Like someone said, "science".

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[Securb]

Re: Why do guitars need intonation?

MATH

 

[GoldenVulture]

Re: Why do guitars need intonation?

Non Linear !

 

[Mincer]

Re: Why do guitars need intonation?

The quick answer is that different size strings tuned to different notes need to be different lengths to more or less play in tune. The frets, being straight across, don't allow each string to play in tune all the way up the neck. So you can 'sort of' compensate for this higher up the neck. But setting the intonation perfectly doesn't help *all* notes. It is a good compromise, though.

 

[Little Pigbacon]

Re: Why do guitars need intonation?

I already know about microtonal guitars and equal temperament vs just intonation.

If it was the thickness, there would be a pattern.

Well, there’s a pattern among the three plain strings, and it’s a pattern that repeats with the three wound strings. The vibrating length of the string gets longer as the pitch drops — at least, superficially — but there’s that offset where you jump from a plain G to a wound D. That’s as much of a pattern as I care to look for.

 

[Demanic]

Re: Why do guitars need intonation?

^^
Indeed. But the length adjustment proportion will vary with the set of strings. A set of EB Cobalts won't be adjusted the same as a set of D'Addario XL's of the same gauge.

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[dave74]

Re: Why do guitars need intonation?

You have to stretch the string to fret it,, and the compensation (saddle adjustment) simply counters that.

 

[Little Pigbacon]

Re: Why do guitars need intonation?

View attachment 84565

 

[Godin15]

Re: Why do guitars need intonation?

Man take it easy. Take another look at your avatar.

 

[beaubrummels]

Re: Why do guitars need intonation?

I already know about microtonal guitars and equal temperament vs just intonation.

If it was the thickness, there would be a pattern.

There is a pattern, it's just the pattern is complex. I think you are forgetting that strings do not vibrate in perfect universally-symmetric arcs. The arc they do make depends on thickness, length, pitch and tension. From that they need different amounts of clearance to vibrate in free air, and that forces different amounts of adjustment to placement of frets and or bridge/nut end points.

 

[AlexR]

Re: Why do guitars need intonation?

Strings are tuned to different notes, but the relationship between the precise structure of the string and its tension at pitch is not fully linear. You will notice that there is a linear relationship of sorts within strings of the same construction. If you look at most guitars then you will see the diagonal patterns of the saddles common to intonated guitars.
The variations in individual guitar saddles are all to do with the variations present in individual guitar setups. Plus in part the way the neck wood flexes with string and trussrod tension

 

[Plessure]

Re: Why do guitars need intonation?

Well, there’s a pattern among the three plain strings, and it’s a pattern that repeats with the three wound strings. The vibrating length of the string gets longer as the pitch drops — at least, superficially — but there’s that offset where you jump from a plain G to a wound D. That’s as much of a pattern as I care to look for.

I have seen that offset, but it's nowhere near a universal pattern. My guitar has regular 9 gauge strings and doesn't look anything like that, while being intonated good enough.

 

[Plessure]

Re: Why do guitars need intonation?

There is a pattern, it's just the pattern is complex. I think you are forgetting that strings do not vibrate in perfect universally-symmetric arcs. The arc they do make depends on thickness, length, pitch and tension. From that they need different amounts of clearance to vibrate in free air, and that forces different amounts of adjustment to placement of frets and or bridge/nut end points.

I'm not forgetting, i just get confused by these extremely tiny and inconsistent differences. What you're talking about seems to allude to distinct ratio differences due to pitch etc - not microscopical adjustments.

I'm not dismissing your answer, but i think if there is a pattern, it is even more complex than being a function of pitch, thickness, tension (which are all more consistent than the saddle positions on guitars).

I may have to settle with all the "science, dude" answers unless i want to go physics.

You have to stretch the string to fret it,, and the compensation (saddle adjustment) simply counters that.

If it was simply that, there would be a consistent pattern and there would be references for saddle placements like there are for string actions.

So now we need to invent the Fret Adjustment Intonation Guitar with mechanized rubber frets and stretchy neck material. When you move the saddle, the entire scale length and all of its active components move. That section of the neck will stretch or shrink, and the fret will move and bend under that string, creating a smooth transition to the next string.

 

[Darg1911]

Re: Why do guitars need intonation?

Have your frets, bridge saddles and strings cryogenically frozen. That will solve everything. It's magic.