Intonation and Flamenco guitars

[johnparchem]

or Intonation and capos

A flamenco player gave me a 650 scale Flamenco guitar that has really good flamenco tone, but with intonation problems. He had a luthier friend who worked on it and made it somewhat better, using the limited amount of saddle intonation available and removing some to all of the 1 mm nut compensation the luthier had. (filed back the leading edge of the nut).

I checked out the guitar and the main issue I found was that nut side of the saddle is exactly on 650 mm (325 mm from the 12th fret). I checked all of the frets and they were all on the 650 mm scale except the first fret was about 1 mm close to the nut.

When thinking about a plan to intonate with both a new nut and and wider saddle, it occurred to me that as flamenco player he often plays with a capo. The cantor calls out the cord voicing and the capo position; so playing open is just a few of many keys and voicing options. My thought is that nut compensation is removed when one capos. I understand that most of the fine intonation work is thrown off anyway once one puts on a capo. What I am having trouble understanding is when considering a guitar with a capo am I worse off with a combination of .6 mm of nut compensation and some saddle compensation, or taking the nut to the zero fret and doing either a open - 12th fret or possibly a 5th - 17th fret saddle only intonation.

Any thoughts?

[Alain Lambert]

I am no expert in compensation, but someone (don't remember who) mentioned something which I am still digesting.
If you compensate the nut and you put a capo on a fret, the total length of the string is still shorter compared to a non compensated. So the nut compensation will make a difference with a capo.

[johnparchem]

I am no expert in compensation, but someone (don't remember who) mentioned something which I am still digesting.
If you compensate the nut and you put a capo on a fret, the total length of the string is still shorter compared to a non compensated. So the nut compensation will make a difference with a capo.

Interesting, I can understand the capoed (the new open) notes being more in tune without retuning, but as soon as I fret a note up the neck I still have some of the same issues that cause intonation errors but now with a zero fret instead of a compensated nut.

[Trevor Gore]

This type of discussion can get very fraught very quickly. The outcome of the argument depends on what going-in assumptions you consciously and/or unconsciously make.

Consider a couple of things:

1) Nut compensation works because it means you have to change the string tension (re-tune) to get the open strings to play in tune, and the tension change affects all notes (all strings, all frets). Done right, nut compensation makes all strings play more in-tune on all frets. This tension change persists whether or not a capo is applied.

2) What is the difference between an F# barre chord and an open E chord played with a capo on fret 2?

[johnparchem]

Thanks Trevor,

I was overthinking it and missed the obvious. A simpler example for your point than either the capo or bar chord is fretting a string in two positions which is also normal. If I am fretting with my ring finger and place my index finger on the same string a couple of steps down the neck there is not a noticeable change.