How to Hear Harmonic Overtones

Sympathetic harmonic overtones, often referred to simply as "harmonics," are a high-pitched, ringing sounds that occur when an instrumental pitch is played with pure and rich enough overtones or when two instrumentalists play with perfect enough intonation. In some cases, it can be difficult to tell whether an overtone is sounding or the sound comes from an instrument. In order to tell the difference between played high notes and harmonics, listen to the quality of the sound and observe the conditions under which you hear it.

Before you start, try to discover the source of the sound. Most musical instruments produce a sound that's too distinctive to be mistaken for a harmonic frequency, but there are some that might be producing a sound you could mistake for harmonics; if no such instrument is playing, you are more likely hearing harmonics. Electronic instruments like electric guitars, synthesizers or a theremin are likely to produce sounds that could be mistaken, as are acoustic orchestral strings.

Note the volume of the sound. Harmonic tones are easy to hear because of their distinctive sound and because they are so high, but they are not very loud. If it's a harmonic sound, you'll have a little trouble noticing and keeping track of it. If it's louder or overpowering, it's not a harmonic overtone.

Listen to the relative pitch of the sound. Harmonic overtones are sympathetic and will occur at pitches relative to the note (played on an instrument) that produces them. The first overtone you will hear will occur at an interval of a perfect fifth; if the tone is pure enough and in tune with others around it, you may also hear an interval of a major third.

Pay attention to the character of the sound. Overtone harmonics have a pure, unwavering sound without any distinctive hitch to the articulation or release. If you don't know what this sounds like, try creating a pitch by rubbing the rim of a crystal wine glass filled with water; the sound produced by a sympathetic overtone is similar to this, though usually much softer in volume.