Classical guitar tuning issue

menamestom

Have just bought a classical guitar from ebay.  If I tune the g string and check the 12th fret harmonic, it is in tune, but fretting it higher up tends to be quite sharp.

The other strings are close enough, but the G string just seems way off.

What are the likely causes, could it just be the strings?  They don't look too old and are not dull, but do you accationally just get a bad one?

Or is it just a case of tuning the guitar differently so it is the best fit for all positions?

JonnyBgoode

menamestom said:

Have just bought a classical guitar from ebay.  If I tune the g string and check the 12th fret harmonic, it is in tune, but fretting it higher up tends to be quite sharp.

The other strings are close enough, but the G string just seems way off.

Its a common problem.  Try these:

Firstly whats the action?  if its too high it will throw out the intonation. About 3.5-4mil at 12th fret 6th string is about as high as you'd want it.

The thickness of a trad nylon G string also exacerbates this issue, try a set of 'carbon'  strings, they have much nicer thinner G strings. CG players often buy packs of carbon Gs to change out the G in whatever set they like. D'Addario Composites also have a thin non-trad G string but its brown and pretty hard. Some people like them.

Having a compensated saddle cut for the bridge will help sort this problem also, but obviously depends on what you want to spend...

menamestom

JonnyBgoode said:

menamestom said:

Have just bought a classical guitar from ebay.  If I tune the g string and check the 12th fret harmonic, it is in tune, but fretting it higher up tends to be quite sharp.

The other strings are close enough, but the G string just seems way off.

Its a common problem.  Try these:

Firstly whats the action?  if its too high it will throw out the intonation. About 3.5-4mil at 12th fret 6th string is about as high as you'd want it.

The thickness of a trad nylon G string also exacerbates this issue, try a set of 'carbon'  strings, they have much nicer thinner G strings. CG players often buy packs of carbon Gs to change out the G in whatever set they like. D'Addario Composites also have a thin non-trad G string but its brown and pretty hard. Some people like them.

Having a compensated saddle cut for the bridge will help sort this problem also, but obviously depends on what you want to spend...

Thanks for the suggestions.

The action seems reasonable for a classical, probably 4mm so could perhaps go lower.  There is ample bridge and a decent break angle to play with so that is something I might try. Perhaps just start with a slight action lowering and new strings.

Possibly try a carbon G.  Guitar is a spruce top (Cordoba C10), sounds really nice, my only thought with carbon is it's probably the opposite direction I'd want the tone to go in as the guitar is already clear and strident.  But in all honesty being in tune is more important that string nuance.

earwighoney

menamestom said:

Have just bought a classical guitar from ebay.  If I tune the g string and check the 12th fret harmonic, it is in tune, but fretting it higher up tends to be quite sharp.

The other strings are close enough, but the G string just seems way off.

What are the likely causes, could it just be the strings?  They don't look too old and are not dull, but do you accationally just get a bad one?

Or is it just a case of tuning the guitar differently so it is the best fit for all positions?

This doesn't sound like a tuning issue but an intonation issue. 

The last time I had an issue I ended up tearing my hair out over it, tried a lot of different strings and in the end my solution was to live with the intonation issues. 

DavidR

I too think imperfect intonation is a problem of many classical instruments. 

Unlike violins, all classical guitars are different. Different dimensions, different plantillas and different builds. I use to play in a classical ensemble of about 12 players, and even though we would stop every hour or so to tune up with digital tuners, there was still an imperfection. 

Admittedly we were all amateurs. However, classicals do regularly detune themselves as they warm up; and they respond to temperature and humidity a lot. 

It’s annoying. Not sure there’s a solution, but others might have a better answer. 

JonnyBgoode

menamestom said:

Possibly try a carbon G.  Guitar is a spruce top (Cordoba C10), sounds really nice, my only thought with carbon is it's probably the opposite direction I'd want the tone to go in as the guitar is already clear and strident.  But in all honesty being in tune is more important that string nuance.

Ok, yes Cordobas are nice, I've owned a few (I have the Stage at the mo). And yeah just changing the G for carbon, it won't be super bright on its own and actually they tend to blend in better IMO, the transition from bases to trebles works better.  I have some Savarez Alliance trebles on my flamenco, very nice. Their G is great.

menamestom

DavidR said:

I too think imperfect intonation is a problem of many classical instruments. 

Unlike violins, all classical guitars are different. Different dimensions, different plantillas and different builds. I use to play in a classical ensemble of about 12 players, and even though we would stop every hour or so to tune up with digital tuners, there was still an imperfection. 

Admittedly we were all amateurs. However, classicals do regularly detune themselves as they warm up; and they respond to temperature and humidity a lot. 

It’s annoying. Not sure there’s a solution, but others might have a better answer. 

Possibly, yes.  I’ve not noticed the issue before, but my previous main classical is a very old laminate guitar, perhaps it is just super stable, or perhaps the tune I’m currently learning  (Evocation) just exposes the inherent idiosyncrasies of the Classical Guitar. 
I don’t have the old one to compare as it lives in Spain now.

JonnyBgoode said:

menamestom said:

Possibly try a carbon G.  Guitar is a spruce top (Cordoba C10), sounds really nice, my only thought with carbon is it's probably the opposite direction I'd want the tone to go in as the guitar is already clear and strident.  But in all honesty being in tune is more important that string nuance.

Ok, yes Cordobas are nice, I've owned a few (I have the Stage at the mo). And yeah just changing the G for carbon, it won't be super bright on its own and actually they tend to blend in better IMO, the transition from bases to trebles works better.  I have some Savarez Alliance trebles on my flamenco, very nice. Their G is great.

Great, will give one a go, may as well experiment a bit.

earwighoney said:

menamestom said:

This doesn't sound like a tuning issue but an intonation issue. 

The last time I had an issue I ended up tearing my hair out over it, tried a lot of different strings and in the end my solution was to live with the intonation issues. 

This may be the final solution - I’ll not lose sleep over it but if I could improve the G string by 40% that would be good enough.  

ICBM

A compensated saddle with the G string break point at the back edge and the others at the front is common on classical guitars for exactly this reason.

BillDL

In the video below the presenter makes a new compensated saddle for her classical guitar.  In the first 3rd of the video she talks about the difference in properties of steel strings vs nylon strings with reference to the way they respond to being pressed down to fret and also the distance forward from the breakover point of the saddle the different types of strings effectively begin vibrating.  The factors she describes explain why the saddle of a steel string guitar is already angled on the bridge whereas on a classical guitar it's usually straight.  On electric guitar strings with an unwound G and on a set of nylon strings with a bare nylon G string, those strings have the largest diameter core and are the stiffest, so the saddle usually needs to be compensated more for that string than for the others.  On a steel string guitar with a wound G it's usually the B string that has the thickest core and the saddle needs to be compensated more on that string than for the others.

On some steel string guitars that have smooth topped saddles you will see an apex like a path along the peak of a mountain with a crest that starts near the front of the saddle at the high E and gradually moves backwards to the rear of the saddle on the low E side, and this is done by sanding the profile of the saddle top so you have a shallow drop-off on one side and a steeper one on the other.  They will usually sand further back into the saddle where the B string breaks over, and sometimes also (but to a lesser extent) for the G string.

On other compensated saddles the compensation filed into the saddle is done like separate ramps side by side with different slopes up to the breakover point, so it looks more jagged in appearance as it follows roughly what you see on a fixed intonation zig-zag wraparound bridge on an electric guitar.

You don't often see compensation on the saddle of a moderately priced production line classical guitar, but you will usually see it on a hand made saddle in more expensive classical guitars.  You can buy compensated bone and synthetic bone classical guitar saddles, but you would have to know the exact dimensions of your existing one.  For example 80mm long x 3mm thick and 9mm high at the bass sloping down to 8mm at the treble, and compensated for the B, G, and D strings:

https://www.vansonguitars.com/products/vanson-80mm-compensated-plus-bone-saddle-for-classical-guitar

or this one that's 80mm x 2.95mm x 9.1mm and compensated for the G string:

https://allparts.uk.com/products/bridge-saddle-for-classical-guitar-bone-compensated-80mm-x-2-95mm-x-9-1mm

There are loads of other retailers, but you have to look carefully at what you are buying.

It usually is possible to carefully sand some G string compensation into a bone or synthetic bone classical saddle yourself using a fine flat needle file or fine grit sandpaper wrapped around a narrow flat piece of wood, but you have to be careful with bone as it is brittle and breaks quite easily.  If you need help finding a pre-compensated saddle that will fit, let us know the dimensions of the existing saddle.

menamestom

BillDL said:

In the video below the presenter makes a new compensated saddle for her classical guitar.  In the first 3rd of the video she talks about the difference in properties of steel strings vs nylon strings with reference to the way they respond to being pressed down to fret and also the distance forward from the breakover point of the saddle the different types of strings effectively begin vibrating.  The factors she describes explain why the saddle of a steel string guitar is already angled on the bridge whereas on a classical guitar it's usually straight.  On electric guitar strings with an unwound G and on a set of nylon strings with a bare nylon G string, those strings have the largest diameter core and are the stiffest, so the saddle usually needs to be compensated more for that string than for the others.  On a steel string guitar with a wound G it's usually the B string that has the thickest core and the saddle needs to be compensated more on that string than for the others.

On some steel string guitars that have smooth topped saddles you will see an apex like a path along the peak of a mountain with a crest that starts near the front of the saddle at the high E and gradually moves backwards to the rear of the saddle on the low E side, and this is done by sanding the profile of the saddle top so you have a shallow drop-off on one side and a steeper one on the other.  They will usually sand further back into the saddle where the B string breaks over, and sometimes also (but to a lesser extent) for the G string.

On other compensated saddles the compensation filed into the saddle is done like separate ramps side by side with different slopes up to the breakover point, so it looks more jagged in appearance as it follows roughly what you see on a fixed intonation zig-zag wraparound bridge on an electric guitar.

You don't often see compensation on the saddle of a moderately priced production line classical guitar, but you will usually see it on a hand made saddle in more expensive classical guitars.  You can buy compensated bone and synthetic bone classical guitar saddles, but you would have to know the exact dimensions of your existing one.  For example 80mm long x 3mm thick and 9mm high at the bass sloping down to 8mm at the treble, and compensated for the B, G, and D strings:

https://www.vansonguitars.com/products/vanson-80mm-compensated-plus-bone-saddle-for-classical-guitar

or this one that's 80mm x 2.95mm x 9.1mm and compensated for the G string:

https://allparts.uk.com/products/bridge-saddle-for-classical-guitar-bone-compensated-80mm-x-2-95mm-x-9-1mm

There are loads of other retailers, but you have to look carefully at what you are buying.

It usually is possible to carefully sand some G string compensation into a bone or synthetic bone classical saddle yourself using a fine flat needle file or fine grit sandpaper wrapped around a narrow flat piece of wood, but you have to be careful with bone as it is brittle and breaks quite easily.  If you need help finding a pre-compensated saddle that will fit, let us know the dimensions of the existing saddle.

Thanks for the info @BillDL ;

I've had a watch of that video now and it's all starting to make sense.   My bridge is 80x3mm so both of the ones you posted should fit.  I'll probably have a go amending it myself, if it breaks it will be easy enough to get a replacement.

First of all I might try a thinner G string and see how that affects it.   I'll probably have a few string experiments first and see how the set I settle intonate then go from there. 

I'm tempted to try some D'addario EJ46LP.  The guitar currently has the ones Cordoba reccomend according to the previous owner which are Savarez Cristal Corum High Tension 500CJ.  I like the idea of the EJ46LP as they reduce finger noise (I'm going to be doing a bit of recording), are slightly mellower and also have a composite G string.
But first I'm just going to try a carbon with the current set.

Then when I've decided on strings I'll see what the bridge needs.   Thanks for all the info, this won't niggle now I know it can be rectified or at least improved quite a bit by compensation and / or string choice.