I was recently contacted by Curtis Laur, a full-time guitar tech who has worked with such bands as Guns N' Roses, Elton John, Little Feat, and Ricki Lee Jones. His experience illustrates the headaches that guitar intonation can bring, even when the guitar is "correctly" intonated. Here is an exerpt from our e-mail conversation:
Been reading through your tuning article. Would like to get a copy of it emailed if I could. I tune guitars in the studio for various national acts and could always use more ideas and help. Thanks. Curtis.
I recommend three things to get most factory guitars in tune:
Then to tune the guitar, get it "in the ball park" by tuning to an electronic tuner, the 4th and 5th frets, harmonics, or whatever. Then play the two "thirdless" chords, E5 and A5, as shown in my Intonation V article, and adjust until they both sound equally in tune.
This will get you in tune with Equal Temperament. For rock and roll, it's sometimes better to fudge on this a bit. You can tune the guitar so the open E chord is perfectly consonant by tuning the A and B strings 2 cents sharp and the G string up to 22 cents flat, but then you can only play barre chords based on the E chord shape. If you play an open A or C chord, it will sound horrible. But for a song that you can play using only the E chord shape, moving it up and down the neck, you can sound REALLY in tune. That kind of trick works well in the studio, but can be limiting live.
With my current project we have spent a lot of time redoing guitar parts because they were out of tune. Tempered tuned guitars are not acceptable with the producer but I don't know of any easy options. We do put some tracks down one chord at a time so I can get the 3ds flat and the 5ths sharp.
I am about 5 articles in but something I would like to know is the cents displacement of every interval. I am using many tuners and I do have a Yamaha PT-100 so I can do adjustments of 2/10s of a cent. Mainly I have been tuning intervals at:
I would like to know the mathematical offsets for all the intervals. Do you have any ideas on this? Tuning the chords by ear does not work for long. We do 12 hour days and I get too fatigued.
Then there is the issue of trying to get a series of chords in tune. Like G to C to D at the nut with the thirds moving to different strings. Any advise on this that you already have not given? I have gone to the extremes of gluing toothpicks to the fretboard. I will entertain crazy ideas but will probably end up with trying to sell tempered tuning to my boss. Thanks,
I found a couple of sites with temperament info:
You should be able to find the offsets in cents for the intervals in there somewhere. The question of course is, what temperament sounds in tune to you and your producer. Sounds like you've arrived at one on your own, which is perfectly legitimate. The various "official" temperaments out there are merely systems people have come up with over the years, trying to compensate for a 12-tone system that doesn't quite fit with the overtone series.
The problem of getting different chord forms to all sound in tune (G to C to D) sums the problem with guitar temperament up nicely. The fretboard is equal tempered, so the best you can do with standard fret placement is to actually achieve equal temperament.
But it doesn't sound like that's really your goal anyway. If you're tweaking 3rds by 11 and 16 cents, you're definitely out of equal tempered territory. Gluing toothpicks to the fretboard is actually a pretty reasonable thing to do - you're making a staggered fret fretboard, as I describe in Intonation IV. You might try getting some fretwire and filing the tang off and gluing little bits of fret bead on instead. This will give you better tone and hold up longer as well. You could have a luthier make you a staggered fretboard guitar or two for a permanent solution. I think there are a few guys making them already, try searching for it on the web. Just understand that you'll need a different fretboard for each key! I remember there was once a company was making replaceable fretboards, so you could swap out for each key.
Good luck -
So you can see that just because the guitar strobes in correctly doesn't mean that it will sound in tune to all ears. Equal temperament is a practical compromise for performance, and is useable for most situations. But under the magnifying glass of the recording studio, desperate measures may be needed to achieve "perfect" intonation.