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intonation??

OK I'm not musically gifted,not a clue how music suppose to sound.(seeing that I'm partially tone deaf and have been all my life and yes I do wear hearing aids but only when watching TV)

if it sound OK to me but be way out to some one who knows.

does it really matter if the intonation is not correct say from the open to the 12th fret it is GDG but the rest is not.

all I know of intonation is high 'n' low in sounds

the reason why I'm asking is that my little 3 sting acoustic that I converted from a 6 stringer.

it is Tune GDG in open to fretted 12th but all others are not is this normal?

set by my tuner 439 HZ

frets......

3rd C ,F,B (all just past the green onto red mark)

5th C,G,C

7th D,A,D

9th E,B,E

12th G,D,G spot on

its a cheap 3/4 acoustic with a flat fret board with brass frets.

it probably only cost about £30/£40 it was nade in the czech republic.

I've since removed the plastic nut and put a bolt on and cut the bridge down as it was sitting to high.

also the bolt some how made it sound better...well it did to me.

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Permalink Reply by Ron "Oily" Sprague on November 24, 2014 at 6:33am

Yep, I'd buy that ;-). No worries, john, press on with your practice git. But truly, reduce the bolt size at the nut, or add a proper nut made of...metal! I bet Randy Bretz could do you one out of brass. And use proper acoustic phosphor bronze steel core strings. You shouldn't have major intonation issues then.

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Permalink Reply by john mackay on November 24, 2014 at 3:51am

now that I've got a bit more time to read above instead of my usual quick read, I now understand what you mean.

upon checking the distance between the nut/bridge and according to gitty scale its about 4 mm out.

gitty scale is measured from fret board edge of the nut to the bridge.

so that means the nut need to be move down so that it measures exactly 24.5".

so I'll do this later at the weekend and we'll take it from there.

typical of me not bothering to read correctly the instructions on gitty scale.

just thought it has to be from the centre and not the leading edge of the nut to the bridge.

luckily the ones that I've made so far the bridges are not glue so I can move them.

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Permalink Reply by john mackay on November 25, 2014 at 7:09am

had a little time spare today and checked the old nut and the measurements don't add up.

it was even worst than the nut that I had on!

I'm going to cut a piece out of the neck and put a bigger piece in to get the distance at the week end.

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Permalink Reply by Ron "Oily" Sprague on November 25, 2014 at 7:49am

Before you do that, stop. Think. The measurement is not necessarily from the end of the fretboard. It is actually from where the nut touches the string: the node at which the string begins to bend over the nut. Which is definitely NOT at the edge of the nut on most guits. It is typically back as much as 2 mm from that edge. Which is why Michael showed the measurement from the center of the bolt. What he showed you as the nut location is actually the location of a zero fret, which would be the crown, or curved top, of the fret if there were one at that location.

Now, since you aren't that worried about if things don't intonate exactly right at all frets, the above shouldn't be bothersome. You can indeed get away with using a bolt. Here's another way to approach this: if you still have the old nut, stick it back on with some tape, or water soluble glue. Measure the scale length from the center of the groove in the nut to the center of the saddle material. Check that scale length on the Stew Mac calculator. Interestingly, the calc also tells you the fret to fret distances. Check those too. If yours are off then you need to adjust your scale length until they are correct. Once you figure that out, then mark the exact location of your nut on the existing space where it goes, and find a bolt whose curve sits back from the end of the fretboard that distance.

Make sure your tuner is set to A440. And realize that even the best intonated guits with straight saddles, or even angled saddles, are compromises, and do not intonate mathematically perfectly. The only ones that do are those with either a) adjustable saddles, which appear on most electric guits, and are properly set up for string height for particular gauges, or b) fractional frets, which look very odd. Everything else is compromise, and most players microscopically adjust their fingering and finger pressure to get things to sound "right."

Or, leave your bolt in place, but cut a slight divot in the headstock where it sits to fractionally lower it, and thus, where the strings impact the fret crowns. Or simply play it slightly out of tune. It's doable. Otherwise, you may stay in the "nut house" for a long time messing with this.

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Permalink Reply by The Phrygian Kid on November 25, 2014 at 12:14pm

FYI with equal temperament a fingerboard which intonates nicely where A4 = 440hz will also intonate correctly @ A4 = 339Hz, A4 = 332Hz etc etc. i.e. not relevant to this particular problem :)

Otherwise GOOD ANSWER !

guitars NEVER play 100% in tune. Better players who are familiar with their axe will unconsciously compensate. Try to HEAR the problem. and try to 'squeeze' a little less when fretting strings.

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Permalink Reply by Michael Fred Johnson on November 26, 2014 at 1:05am

Don't start cutting the thing up ! The fretting must be correct for the scale length (distance from nut to saddle) of that particular guitar.The scale length is not necessarily the same as Gitty's,it's probably in millimetres anyway.