OT:Tuning a guitar using and Equal Temperament method

[Michael Spalding]

Steve,

I am an amateur (novice) luthier, currently playing both classical and
12-string of my own making.  I tune these two instruments diferently, just
as we tune every piano differently.  Different scale designs, condition of
strings, condition of frets, action height, intonation (the bridge and nut
adjustments your referred to).  For each of my 2 guitars, I have learned
what the E6 to E1 double octave should sound like.  Within those bounds,
ever-so slightly wide 4ths are set.  Then I check 3rds on the same string
pairs, fingering the lower string at the first fret and leaving the upper
string open.  Depending on the guitar, you might get evenly increasing 3rds
including the open G3-B2, or you may only get them "not too far out of
line".  I then do a variety of checks on fretted note pairs, because that
is the real world.  How compromised these intervals will be depends on the
quality/condition of the guitar and strings.   If the intonation is not
right, if the strings are old and false ( or just the wrong strings for the
guitar), the compromises will be pretty severe, but that's the best you can
do under the circumstances.

Intonation and other setup adjustments are critical.  Like regulation and
voicing, the attention they get from new guitar dealers ranges from total
attention to detail, to total negligence.  To learn more about it, visit
the Musical Instrument Maker's Forum:  http://www.mimf.com/
or pick up a copy of the Guitar Player Repair Guide by Dan Erlewine.

hope that helps

Mike


> (I posted the following to a Classical Guitar Forum)
>
> Any methods using fretted partials (harmonics) will introduce an  
> error due to the Pythagorean comma (http://en.wikipedia.org/wiki/ 
> Pythagorean_comma) if you are trying to produce an equal temperament.
>
> I tune pianos aurally and have found that I can use basically the  
> same method I use on pianos, on guitar. It is simply this:
>
> Tune your 5th string (A) to a fork or an electronic tuning device.
>
> Sound your 5th and 6th string together. Listen for the beats produced  
> what would be the 5th fret partial (harmonic) on E and 7th fret  
> partial on A. Make the E-A interval slightly wide, 1 or 2 beats per 5  
> seconds.
>
> Do the same for A(5th string) to D(4th string). Again listen for the  
> 5th-7th fret harmonic beats and make the interval slightly wide, 1-2  
> beats per 5 seconds. It shouldn't sound like "beats" really, just a  
> slow roll.
>
> Do the same for D(4th string) to G(3rd string), making the interval  
> slightly wide, but not as wide as the lower strings.
>
> Tune the E(1st string) to the E(6th string) as pure a double octave  
> as you can, or maybe just slightly wide.
>
> Then tune the B(2nd string) to E(1st string) at 1 beat (or less) per  
> 5 seconds.
>
> I then check intervals of a 5th on the open A(5th), D(4th), A (2nd  
> fret on G 3rd string), D(3rd fret on B 2nd string), A (5th fret on E  
> 1st string) and make sure they are slightly narrow.
>
> If you've nailed it, the G(3rd string) to E (1st string) interval  
> sounded together will produce a beat of about 8 beats per second.
>
> This sounds helluva cumbersome, but once you get used to it you can  
> tune a guitar in 30 seconds or less with it. :-)
>
> If the guitar was WAY out of tune to start with, do the process again  
> to balance string tension. Keep in mind that cruddy strings and a mal- 
> adjusted bridge/saddle/nut will affect tuning greatly. Bridge and nut  
> adjustments are best left to a luthier, IMHO. :-)
>
> It takes me between an hour to an hour and a half to tune a piano, so  
> I consider my self lucky I play guitar!
>
> I'd be interested to hear if anyone uses a similar technique or finds  
> this to be useful. If you are new to tuning guitars, this is NOT the  
> technique for you. It takes a while to train your brain to be able to  
> filter through what you are supposed to be listening to using this  
> method.
>
> Happy tuning!
>
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