Originally Posted by Elspode

So strange is this problem on a guitar, that differently fretted instruments are produced to make up for this inherent problem...

http://www.btinternet.com/~steve.sed...Pythagorus.htm

http://www.novaxguitars.com/Pages/fr...toGallery.html

I have a $2k Martin HD 28, the instrument I have desired my entire guitar playing life, and it still suffers from the inability to have any given note on the neck be exactly the same as the same note somewhere else on the neck. I even go to the extent of tuning my low E string differently for songs that use predominant Em themes (highly prevalent in Pagan and traditional music) and songs that use predominant G major themes. Basically, if you tune the low E so that it sounds right with an Em or E maj chord, it sounds out of tune when you play a G rooted chord, and vice-versa.

Nothing wrong with the instrument, it is just how they are made. The links above show a couple of different approaches to addressing this issue, with the most radical being the "fanned fret" approach of Mr. Novax. Fascinating.