intonation

[varmonter]

I have a 45 year old 12 fret martin d28s.
This guitar is a cannon.i really love the tone.
But when i use a capo i have to retune it
Every time.even open i generally tune
The low e string by fretting the g on the 3 fret
And tuning to that g. I am assuming
The intonation is a bit dorked.
What can be done if anything to fix this.?
Are there adjustable saddles for acoustics.
Like on electric guitars.??

[murrmac123]

Originally Posted by varmonter

I have a 45 year old 12 fret martin d28s.
This guitar is a cannon.i really love the tone.
But when i use a capo i have to retune it
Every time.even open i generally tune
The low e string by fretting the g on the 3 fret
And tuning to that g. I am assuming
The intonation is a bit dorked.
What can be done if anything to fix this.?
Are there adjustable saddles for acoustics.
Like on electric guitars.??

Wow, my first Martin was a 12 fret D28-S as well ...I bought it (new) in 1974 so yours is pretty much the same vintage.

I don't recollect that the intonation on mine was suspect, but it is always possible with 70's Martins that the bridge placement is out of whack ... I think you should definitely take it to a competent tech and have it checked out.

Are there adjustable saddles for acoustics.
Like on electric guitars.??

Don't even think about it...

[Hot Vibrato]

Originally Posted by varmonter

I have a 45 year old 12 fret martin d28s.
This guitar is a cannon.i really love the tone.
But when i use a capo i have to retune it
Every time.even open i generally tune
The low e string by fretting the g on the 3 fret
And tuning to that g. I am assuming
The intonation is a bit dorked.
What can be done if anything to fix this.?
Are there adjustable saddles for acoustics.
Like on electric guitars.??

You need to replace your frets or level the existing ones.

You're barking up the wrong tree. Saddle location will only affect the intonation of the notes higher up the neck. The fact that the problem is at the first few frets indicates that the problem is either with the frets, or the nut slots aren't deep enough, or both. My guess is after 45 years of play, the frets are unlevel.

[Ned Milburn]

Originally Posted by varmonter

I have a 45 year old 12 fret martin d28s.
This guitar is a cannon.i really love the tone.
But when i use a capo i have to retune it
Every time.even open i generally tune
The low e string by fretting the g on the 3 fret
And tuning to that g. I am assuming
The intonation is a bit dorked.
What can be done if anything to fix this.?
Are there adjustable saddles for acoustics.
Like on electric guitars.??

First, any time you add a capo, you will need to do some fine tuning. Capos give differing amounts of tension on different strings. Tuning with a capo is also problematic since the tension is "held" by the capo, so you need sometimes to pull strings on either side of the capo to balance the string tension, otherwise, after a few strums, you'll be out of tune again.

This cannot be overstated!

Second, beware of advice saying you need to replace or level your frets. If indeed the intonation is out of tune on the lower frets (specifically sharp), this is usually an indicator that the nut slots are not cut low enough.

Check your nut slots. Lots of advice on this forum and elsewhere how to do so. If the nut slots are fine, then your issue is likely a capo tuning issue.

I'll repeat in a different fashion... Do not tune your guitar open and then expect it to be perfectly in tune with a capo on.

[Hot Vibrato]

Originally Posted by Ned Milburn

...beware of advice saying you need to replace or level your frets. If indeed the intonation is out of tune on the lower frets (specifically sharp), this is usually an indicator that the nut slots are not cut low enough.

Adding a capo can indeed be tricky when it comes to tuning, but I inferred from the OP (perhaps mistakenly) that the intonation on the open chords is wonky without the capo as well, which would lead me to look at the condition of the nut and the frets.

On early 70's Martins, what I usually see is worn and/or unlevel frets, which causes intonation problems at the first few frets. This is common on any guitar that has been played much, especially on 70's Martins, which had awful fretwork to begin with. However, the importance of having the nut slotted to the correct depth cannot be overstated, and this is a common cause of intonation problems near the nut, particularly on guitars that have never had a good setup.

[pops]

I never tune with the capo on, it will bind the strings and they will change as you play.. Proper placement of the capo will help. I put the capo right at the fret so as not to bend the strings, enough tension to seat to the fret, but not bend the strings. and the biggest concern is the placement of the capo on the back of the neck, it should be where it conforms to the neck so as not to pull the capo sideways when tightened up. I never have to retune when putting on a capo and like I said always tune without the capo on. Spending an extra 30 seconds carefully putting on the capo has it's rewards.

[rogthefrog]

Originally Posted by Ned Milburn

First, any time you add a capo, you will need to do some fine tuning. Capos give differing amounts of tension on different strings. Tuning with a capo is also problematic since the tension is "held" by the capo, so you need sometimes to pull strings on either side of the capo to balance the string tension, otherwise, after a few strums, you'll be out of tune again.

This cannot be overstated!

Second, beware of advice saying you need to replace or level your frets. If indeed the intonation is out of tune on the lower frets (specifically sharp), this is usually an indicator that the nut slots are not cut low enough.

Check your nut slots. Lots of advice on this forum and elsewhere how to do so. If the nut slots are fine, then your issue is likely a capo tuning issue.

I'll repeat in a different fashion... Do not tune your guitar open and then expect it to be perfectly in tune with a capo on.

Do the nut slots matter at all for intonation when a capo is in use? To me this seems like the usual capo fine tuning as opposed to a problem with the guitar.

[Bruce Sexauer]

Nut slot height is the most common problem effecting intonation, in my opinion. If they are not right the strings are stretched out of proportion both when fretting or when fitting a capo, also moving a capo from one position to another will then give inconsistent results. The average guitar that comes into my shop has easily criticized nut slots, so the problem appears to be endemic. An extra .01" makes an audible difference, and I often see .05".

[varmonter]

Thanks for the responses.let me try to clarify a bit.
If i tune the guitar perfectly.when i fret a g note
Perfectly without stretching it either way .it is
Sharp about 2 cents.if i hit an open e and fret
Or harmonic the 12th and fret its sharp about 3 cents.
I use an Elliot capo custom made for the guitar.
It has a wide neck.i Always have to re-tune
The low e and b string.. how do i tell if the nut slots is to high
Or if the frets are not level.??
The guitar doesn't seem to have been played
There are no scallops on the fret board.
Thanks again..

[murrmac123]

Originally Posted by varmonter

. how do i tell if the nut slots is to high
Or if the frets are not level.??

The levelness or otherwise of the frets is not causing your intonation problem, if, as you say, there is no fret wear.

If I understand you aright, you are saying that the fretted note at the 12th fret is 3 cents sharp compared to the harmonic ?

Still sounds like a misplaced bridge to me .... get a tech to have a look at it, and at least eliminate that as a possibility.

We could go on guessing all night ... have it checked out by an expert.

[varmonter]

oops no sorry.. the harmonic or fretted note at the 12th fret is 3 cents sharp
to the open e note. the open e or the harmonic is 3 cent flat of the fretted 12 fret note...sorry for the confusion.

[Bruce Sexauer]

One cent is considered very close in a guitar intonation perspective; much closer than "close enough for jazz".

[Bruce Sexauer]

Originally Posted by varmonter

oops no sorry.. the harmonic or fretted note at the 12th fret is 3 cents sharp
to the open e note.

I would have said that the 12th fret harmonic cannot be other than an octave of the fundamental. The fretted note is another thing. If the fretted note at the 12th and the harmonic are the same you are golden. If you are right, however, I suggest the first thing to do is put on new strings, because it really shouldn't be possible to have the discrepancy you describe between the open note and the 12th fret harmonic. Therefore I'd suspect a flawed resonance in the open note making it functionally unhearable (dead string).

Originally Posted by varmonter

oops no sorry.. the harmonic or fretted note at the 12th fret is 3 cents sharp to the open e note.

Like Bruce, I'm not quite following that. The indicator that you have an intonation problem is a difference between the harmonic and the fretted 12th fret note, not between the harmonic and the open note.

With this guitar it could be several things...

Someone could have dressed the frets, but not lowered the nut slots. High nut slots cause the guitar to be hard to play and bends the fretted notes sharp.

It has a square tube neck, which is prone to excessive relief. Like high nut slots, fretting is more difficult than it should be and the fretted notes can be sharp.

The bridge could be too far forward. This is not uncommon on Martins of the period.

There are other possibilities, but I'd start by looking at those things.

[varmonter]

I have read on the tusq website that if i fret the 3rd fret and measure the difference from the top of the fret wire to the string on the first fret
it should be .01 on the low e and .006 on the high e...this would tell be
that maybe the frets were dressed but the nut not lowered..??