Not another stupid question - Part 2; string tension and intonation

michelew
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Thu Sep 27, 2012 4:38 am

I assume the answer to this is a resounding 'no' or 'don't be stupid how could that affect it?", but I'm asking anyway.

Is it possible for the intonation of a stringed instrument to change if the tuning is changed from standard tuning, specifically lowered?

My ukulele is sounding a bit off. I keep checking the tuning and I'm having a little trouble getting the nominally 'high G string' on my ukulele (enter Tony with high-G-String joke - ooow sounds painful)... to stay at F and when I checked it's tuning against the next string by fretting at the fifth fret I started to notice that the intonation is a little out for some/most of the frets....That is, if the open string is in F then the subsequent notes up the neck are too high by different amounts. Grrrrr!

I'm assuming that this has everything to do with fret placement and nothing to do with string tension due to it being tuned down a whole step. But, can string tension affect it, the ukulele's intonation that is? I'm noticing the difference (some dissonance) more in the chords I'm playing at the moment for some reason.

So Bear, Uncle Walt, have I achieved 'stupid question' status yet? ;) Do I get a ribbon or something? :)

Shel


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neverfoundthetime
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Thu Sep 27, 2012 4:51 am

Hi Shel... can I get a medal with a ribbon too if I ask... do what?
Admittedly, I have not consumed enough coffee this morning for my brain synapse to fire properly but I don't think I understand the question (in a sensible way that is!). I'm tuning down my guitars often, mostly a half step but sometimes a whole. What do you mean by "changes the intonation".? Tuning string to string often sounds out as its unfamiliar if you've tuned down a half step or more... could this be the issue? Using the electronic tuner solves that.

PS: Do they serve coffee and sticky buns in the dunces corner? ;-)


michelew
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Thu Sep 27, 2012 5:02 am

Chris - "do what?" ..???...I don't understand your question. I've gone back and corrected some bad typos - none to do with do or dodo for that matter though. :)

I'm already tuning against an electronic tuner which is why i KNOW the intonation is out. Otherwise I'd just assume it was my crappy listening/pitch perception.

Coffee - well you do need to get the dosage right for your drug of choice - mine is also the dark elixir. Good luck with that.


OK now back to cracking up in front of the camera while singing badly. :)

And to answer your question Chris, there's only tea here in the dunce corner, there's no sticky buns either and ALL of the chocolate has been snaffled by some crazy, green-eyed chocoholic.


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neverfoundthetime
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Thu Sep 27, 2012 5:37 am

Had another coffee and am still struggling.
You mean pitch when you say intonation? Or do you mean something subtler by intonation?
"Do what?" just means, what do you mean, I'm trying to understand your question more precisely.
It seems that you are saying that when you have the G tuned to F, your other strings sound out of tune... or are out of tune (which you established with the tuner check). You are wondering if having reduced tension in the strings effects the calibrations of the frets? we're talking nylon strings I guess... always seem more dificult than steel to get and stay in tune.

I admit, I am distracted by the view out of the window here in Magglingen, 1000 Mtrs up and watching the Eiger, Mönch and Jungfrau fade in and out of view in the distant smoking of the clouds.... not too helpful for concentrated thinking!


michelew
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Thu Sep 27, 2012 5:48 am

Yes nylon strings - got to love 'em. They do sound great though.

OK - I haven't checked the intonation of my uke, whether the pitch is correct at each fret once the open string is tuned to a specific note, when I'm in standard tuning. So I'm guessing that any issues I'm having with the pitch of each note and the sound of each chord is the same regardless of whether I'm in standard tuning or tuned a whole step down (which I am now).

So I guess I'm assuming that the frets on this uke are not placed quite where they should be.

But, I was wondering whether the fact I have lowered the tension in the string has any effect whatsoever on the pitch at each fret. I assume the answer is no because the frets really just divide the string up into different lengths.

OK - I award myself the 'stupid question' medal. I must get some more beverages and chocolate in this dunce corner. :)


OK as you were - back to regular programming.


Chasplaya
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Thu Sep 27, 2012 6:02 am

I don't believe the intonation would change due to changing tuning, intonation is the built in factor of the position of the frets, fingerboard string length etc, i.e an open E should be an octave higher at at 12th string of a guitar so I presume its the same deal for Uke's Hmm interesting wonder if some of the guru's out there with tech knowledge can add to this


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neverfoundthetime
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Thu Sep 27, 2012 6:23 am

Shel, you know that secretly I really believe there are no stupid questions (Walt's example doesn't count as that is deliberately stupid and when we are in a questioning state of mind we are intuitively at our most intelligent, IMHO). There are lazy ones as anyone with a teenager will know round about homework time!

I've always wondered what the effect of the thickness of the strings is. I use light strings which I am assuming are thinner than "hard" strings which I hate as they hurt the hell out of my fingers and make playing an unnecessary pain. The thickest string on my 12 is always out at any fret although the other strings aren't (or hardly). When using a capo that would make sense but its also true when open.

The coffees in the D corner are on me!


michelew
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Thu Sep 27, 2012 7:10 am

Thanks for being so supportive Chris and the chocolate in the D corner is on me. Oww and I'd better source some sticky buns. :) See you there again soon. ;)


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daryl
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Thu Sep 27, 2012 7:36 am

I don't think this question is stupid at all!

Here is a really interesting article on intonation......http://www.pjguitar.com/website/forums/ ... ation.html

It specifically says, "....The pitch rule tells us that a guitar will display a global tendency to more sharpness as the open-string pitch goes down...."


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neverfoundthetime
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Thu Sep 27, 2012 7:52 am

Thanks Daryl, that's a helpful link.

I was wondering about Pitch and Intonation so looking it up in Wiki was helpful:
Intonation, in music, is a musician's realization of pitch accuracy, or the pitch accuracy of a musical instrument. Intonation may be flat, sharp, or both, successively or simultaneously.
So its accuracy of pitch of the instrument at whatever fret.
The wording " musician's realization of pitch accuracy" is confusing to me as realisation can mean to achieve or to become aware of / understand... so does it mean the musicians perception/understanding of the instruments accuracy or the achievement of it by the instruments correct calibration? You see, I was born in the Dunce corner! Questions upon questions.

This was useful too....
Several factors affect fretted instrument intonation, including depth of the string slots in the nut, bridge saddle position, and the position of the frets themselves.

On fretted string instruments, pushing a string against a fret—aside from raising the string's pitch because it shortens the string—also causes a slight secondary raise in pitch because pushing the string increases its tension. If the instrument doesn't compensate for this with a slight increase in the distance from the bridge saddle to the fret, the note sounds sharp.
From Daryl's link:
Obviously it is necessary for the spacing of frets to be accurate if good intonation is to be achieved. Yet it is amazing how many guitars, especially luthier-made instruments, have inaccurately spaced frets. Whenever a guitar refuses to play in tune, fret spacing is the first thing that needs to be checked.


Assuming fret spacing is accurate, the second important variable affecting intonation is the stretching of the string which occurs when a note is fretted. This stretching increases the total length of the string, which increases the tension on the string, just as if we had tuned up with the tuner, and therefore causes the note to play sharp.


Things are not quite this simple, however. Each string behaves differently with regard to sharping tendency when fretted. There are three related rules which apply here: sharping from fretting is inversely proportional to pitch (the pitch rule); pitch is proportional to string tension (the tension rule), and; string tension is proportional to string mass (the string mass rule).


The pitch rule tells us that a guitar will display a global tendency to more sharpness as the open-string pitch goes down, and the Eb string does in fact go sharp more than the Et string. However, the tension rule and the string mass rule also come into play, and we see this especially when we compare the sharping behavior of the G and D strings. If we were to apply the pitch rule only to G and D, we would expect more sharping from D than from G. But D in fact sharps less than G. This is because of the metal windings on D which add mass. Even though D is lower in pitch than G, it has higher tension than G and therefore sharps less. If you want to test this, you can tune your monofilament G-string down to D; the string will now sharp more than when it was tuned to G.


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