Did you know that it’s impossible to tune a guitar perfectly? I don’t mean impossible as in, “It’s impossible to play an entire gig without some joker yelling ‘Freebird!’” I’m sure that’s happened somewhere. I mean impossible as in, Swedish-physicists-in-lab-coats-standing-around-a-guitar-shaking-their-heads impossible.
To fully explain why, we’d need to talk about Greek philosophers experimenting with harps, and Bach’s contemporaries arguing about how to get an orchestra in tune, and there’d be lots of charts, graphs, and ratios involved. I’m unqualified to do any of this.
Here’s a brief explanation though, to the best of my knowledge
Looking at the fretboard of the guitar, you’d get the impression that our musical system is very orderly. Those perfect parallel frets line up so nicely, diminishing in width at an even rate as they move up the neck, like the world’s straightest sidewalk stretching into the distance. What if I told you that in order to get the guitar to play perfectly in tune, that sidewalk would look like a bomb landed on it? And even then, you could only play it in one key? This is what I’m talking about.
Time for an example. Most of you know the way of tuning your guitar by ear, where you tune pairs of strings by playing the 5th or 4th fret of the lower-pitched string. Those of you who are really sensitive to tuning have probably noticed that by the time you’re done, you compare your 1st string to your 6th (both E notes) and that 1st string is sharp! “Arrgh! I knew I should have bought that extended warranty!”
Actually, there’s nothing wrong with your guitar. Or rather, David Gilmore’s Strat has the same problem. The problem is, the note you play on the 5th fret of your guitar is ever-so-slightly sharp compared to the open string note. Every time you tune a string, you introduce a little bit more sharpness, so that by the time you get to the first string, you’ve drifted out of tune. It’s like the game of telephone—error on top of error on top of error.
The distance between an open-string note and a 5th fret note is called an interval of a fourth. Where things really start sounding out-of-tune is when you play the interval of a third. Try tuning your guitar with an electric tuner, and then play the open third and second strings—this is an interval of a third. That second string sounds a tiny bit sharp.
Why is this? Basically, nature handed us a spiral, and for the last 500 years we’ve been trying to figure out how to squish it into a circle. The best we’ve come up with so far is the system we use today, called “equal temperment”. Google this term and you can learn more. Be prepared for some math.
In the meantime, how should you tune your guitar? First of all, the electric tuner is superior to that fretting-the-fifth-fret method. It appalls me how often I hear about guitar teachers who force their students to always tune by ear using that method. Sure, it trains your ear, but shouldn’t the primary goal be to get the thing in tune?
There is a tuning-by-ear technique that does work great, described by Richard Lloyd (guitarist for the awesome 70’s punk band Television). It’s harder to memorize, but it’s worth it! You can find it on his website’s FAQ here, second question down.
But ultimately, you’re going to have to put up with your guitar being a bit out-of tune. If it’s any consolation, pianos and other fixed-pitch instruments have the same problem.
And if you just can’t stand it, you can always switch to an instrument like trombone, where you have full control of your pitch.
Of course, you can’t play a trombone behind your head or light it on fire….