Ever have one of those guitars that sounds ok on
some chords, but sounds terrible when you try to
other chords? Chances are your intonation is out. Correct intonation is
what allows the guitar
to play in tune at different places on the neck. This is achieved by adjusting
the length of each
string, to compensate for the fact that the string stretches when you
push it down to play a note. And
every string stretches slightly different amounts. Most electric guitars
have individual bridge saddles
to allow for precise adjustments. Acoustic guitars have compensated bridges,
meaning they're pre-
angled to achieve approximate intonation. Not as accurate up high, but
most acoustic guitar is played
on the lower 5 frets, so it works. Some companies have even come out with
a staggered bridge, to
further raise the level of intonation on their acoustic guitars.
To set intonation, you move the bridge saddle of a string up or back until
the note at the 12th fret is the
same as the harmonic at the 12th fret. The object is to have the note
of the open string be exactly one
octave lower than the note on the 12th fret of the same string.
Before you set the intonation, you should make sure that the string height
is where you want it, the
truss rod is set the way you want it, and your pickups are set correctly.
All these things, when changed
can affect your intonation. Also, always check intonation with new strings,
and make sure that the
guitar is tuned up. Once you're ready, it's a fairly simple procedure.
First: with the guitar laying down, so no undue
pressure is being applied, play the 12th fret harmonic of
the 1st string. With a tuner or strobe(preferably), tune it. Then check
the fretted note at the 12th fret. Try
to just use enough pressure to sound the note, and be sure not to bend
it at all. If the fretted note is sharp,
then the string is too short. Move the saddle away from the neck a little,
and check it again. If it's flat
compared to the harmonic, then move the saddle towards the neck. When
the 2 notes are the same, move
to the next string. I usually check all 6 strings, and then repeat, just
to be sure. That's all there is to it!
A couple of things to consider: If the intonation
is bad at the bottom, and actually gets better as you go up
the neck, the nut could be off. That would make the whole scale be off.
You should have it checked by a
pro. Also, if even after adjusting the bridge saddles as much as they
allow, the intonation is still off, you
might have to move the bridge. I actually had a Les Paul with a misplaced
bridge from the factory! Never
could get it right! Finally had the bridge reset, and voila! So never
assume anything, and just take your
time. Good intonation will be worth it.
.................................That's it! Now go
play, or look at some other tunings, next page...............................................