Tuning With Harmonics - It Doesn't Work. by Larry P. Schrof, Copyright 2003 As guitarists, we've all been there. You've just finished one of your songs at a gig, and a couple of your strings are noticeably out of tune. You've only got about 10 seconds of dead air before the crowd gets antsy. (Not to mention the drummer will probably start muttering obscenities normally reserved for practice sessions.) No problem! Just pluck the 5th fret harmonic of your lowest string and the 7th fret harmonic of the next string. Adjust the second string until its harmonic is in tune with the first, and move on to the next pair. It's quick and effective, right? WRONG. Tuning the guitar using harmonics is probably one of the most common mistakes guitarists today make. Yes, I know - everybody does it. You've probably been doing it for years, and it seems to work. Why, even books and web list it as one of the common methods of tuning a guitar. In this article, I'll explain why tuning with harmonics is not reliable. You'll need to put on your thinking cap for a bit. I'll try to keep the math to a minimum. It won't hurt too much, I promise. First, we need to start with some basic facts about string acoustics and the open-string notes. When you play a 5th-fret harmonic, it produces a frequency four times (exactly two octaves) higher than the open string note. When you play a 7th-fret harmonic, it produces a frequency exactly three times higher than the open string note. (Even though this harmonic SOUNDS like a perfect fifth, it is not, and THAT makes all the difference. More on this in a minute...) Next, we need a list of the frequencies that a perfectly tuned set of guitar strings will produce. Assuming equal temperament using A-440, we get: Open Note Frequency -------------------- Low E: 82.41 A 110.00 D 146.83 G 196.00 B 246.94 E 329.62 Using this information, you can now determine the frequencies produced by the 5th and 7th-fret harmonics on every string. For example, since the A string rings open at 110 Hz, its 7th-fret harmonic will be at 330 Hz, and its 5th-fret harmonic will be at 440 Hz. OK. Now that the groundwork is laid, let's see why tuning with harmonics doesn't work. We'll walk through an example. Assume that your low E and A strings are in perfect tune, but you want to double-check them. According to the chart above, your low E string will produce a tone at 82.41 Hz. Using the method you all know and love, you'll pluck its 5th-fret harmonic. This gives an E two octaves higher, at 329.64 Hz. Then, you pluck the 7th-fret A-string harmonic and get a 330 Hz tone! Ah hah... do you see the problem? The 330 Hz harmonic of the *PERFECTLY TUNED* A string will sound sharp to you, and you'll detune it to match the E-string harmonic. What you're actually doing, though, is tuning the A string flatter than it should be by about 0.12 Hz! Doesn't sound like much, does it? Well, the A string is now almost two cents flat. That's not good news, and the problem gets worse. You are now going to be tuning the next string off of a string that's already flat. Let's see what happens. Our now-flat A string is ringing open at 109.88 Hz. You pluck the A-string 5th fret harmonic, then adjust the D-string 7th fret harmonic to match. When the harmonics align, the D string will now ring open at 146.51 Hz. Take a look at the chart above. We're 0.32 Hz too low. The D string is now almost FOUR cents flat. Notice how the error becomes larger. Continuing in this manner, the G string will end up almost 6 cents flat. Now THAT'S a noticeable difference. Some people like to match the D-string's 9th fret harmonic to the B-string's 5th fret harmonic, but that won't work either. In general, tuning strings to any harmonics besides octaves of the open string notes will yield flawed results. Of course, this all begs the question - how should one tune? Ideally, you should use an electric tuner on each string. If using a tuner is not an option, tune your high E string to a known correct pitch such as another (already-tuned) instrument. Play the 5th fret of your B and match it up to the high E. Proceed the same way down all the strings, tuning your low E string last. If you're like me, you found all of this a bit surprising at first, but hopefully a little enlightening. (I personally had been using harmonics to tune for years.) Needless to say, playing an out-of-tune guitar not only sounds harsh, it sounds unprofessional and amateurish. So let's get the credit we deserve as players and stop using harmonics to tune! Practice hard, - Larold