What temperament is a guitar tuned?

[Keith McGavern]

You did a terrific job, Tim, of describing the uniqueness of tuning guitars
and the particular characteristics of the instrument in your post (below).
I can't imagine anyone doing better!  All of your subsequent posts further
support your explanations as well.

Owner of over 25 guitars (electric, classical, & acoustic) during my guitar
experience.

Thank you,

Keith A. McGavern
kam544@ionet.net
Registered Piano Technician
Oklahoma Chapter 731
Piano Technicians Guild
USA

>John, Bill & List:
>
>
>Billbrpt@aol.com wrote:
>
>> The guitar's frets are laid out in a manner that would imply ET.  All
>>  electronic guitar tuner's frequencies are based on ET. However, many players
>>  will tell you that once they have tuned  according to the elctronic tuner,
>>  they play some chords and "tweak" the tuning a bit to suit their own
>>  preferences.  Many who do this are essentially converting the ET to a WT.
>>
>
>Guitar frets on all modern guitars that i know of are laid out at a
>factor of 2^-12, just like an equal tempered piano scale. Because the
>guitar interface is a 2-dimensional matrix rather than linear and because
>the intervals are fixed in the dimension along the neck, you can
>only alter the intervals between the open strings. Any attempt at using
>other temperaments results in different harmonic results depending upon
>how you voice any given chord and which form (or "shape") of the chord
>you use.  Very few guitars I have played have perfect intonation,
>although inharmonicity is low compared to that of pianos because the
>tension is so much lower and the strings thinner and less stiff.  The
>intonation of any guitar is affected by the choice of strings (why most
>electrics have compensating bridges), the age of the strings (older
>strings are less elastic and go sharper when pushed to the fret than
>do new ones, and have higher inharmonicity) the action height (the higher
>the string is above the fretboard, the sharper it goes when it it pressed
>down to the fret) the height of the frets and the technique of the
>guitarist (how close the finger is to the fret, how far the string is
>depressed below the crown of the fret, and the amplitude of the vibration
>(if you watch with a visual aid, you can see that a loud note is sharper
>than a quiet one, especially in the bass).
>
>Any time you tune a guitar, you try to make the best compromise for the
>piece you are playing, so that as many as possible of the actual
>intervals to be used will sound tolerable.  I have never seen an
>electronic tuner that will do a satisfactory job on a guitar. I don't
>know any accomplished guitarists that use them, although I know of some
>roadies that use them to put stage guitars "in the park" before a
>performer picks them up, and I know luthiers who keep one on the bench
>for analytical purposes. I am sure you could store a good average aural
>tuning for a given performer on a given guitar with a given set of
>strings of a given age on a SAT.
>
>When I tune, I set my open fourths to about 1 beat per second wide, the
>third between G and B to roughly 8 beats (no, I don't count) make sure my
>fifth-fret unisons (and 1 fourth fret) are tolerable, check the
>coincident 3rd and 4th partials of adjacent strings(7th and 5th frets),
>and the 4th partial of E against open e, and then play a bunch of chords
>to find any intolerable intervals.  And of course, all of this only
>applies to standard tuning (EADGBe)  There are many guitarists using
>non-standard tunings, a lot of which are tuned to an open chord, or
>something approaching one (such as DADGad) and in which it is possible to
>push the tuning (of the open chord) towards "just intonation", since most
>of the compositions played this way are strongly tied to the home key,
>and the occasional crunchy excursion is soon satisfyingly resolved.
>
>Tim Keenan
>Terrace, BC