Overtones

What it is

An overtone is a frequency present in a sounding note above its fundamental pitch. A chromatic tuner makes this easier to work on alone. The acoustics section covers the rest of this group.

Every note a violin produces is not a single frequency but a stack of them: the fundamental, which the ear identifies as the pitch, plus a series of higher components sounding simultaneously.

These higher components are the overtones, also called partials or upper harmonics.

Why they exist

A vibrating string does not only vibrate along its whole length.

It also vibrates in halves, producing a frequency twice the fundamental. In thirds, producing three times. In quarters, four times. And so on, in principle indefinitely, though the higher components become progressively weaker.

All of these happen at once, superimposed on each other. The string's actual motion is the sum of them.

Why they matter

Overtones are what make a violin sound like a violin.

Two instruments playing the same pitch produce the same fundamental. What differs is the balance of overtones above it.

A violin, a flute, a clarinet and a human voice singing the same note all produce identical fundamentals. The ear distinguishes them entirely by which overtones are strong, which are weak, and how they behave over the duration of the note.

Remove the overtones and you have a sine wave, which sounds like nothing in particular.

How bowing changes them

This is the part directly under a player's control, and it is why contact point matters so much.

Near the bridge, the string is stiffer and under more tension. The bow excites a rich set of upper overtones. The sound is bright, edgy and complex.

Over the fingerboard, the string is most flexible. Fewer upper overtones are excited and the fundamental dominates. The sound is soft, hollow and pure.

Sul ponticello and sul tasto are the two extremes of this, and everything between is available continuously.

Bow pressure also affects the balance. More pressure generally brings out more upper overtones, up to the point where the string is choked.

Bow speed interacts with both.

A player controlling contact point, pressure and speed is controlling the overtone balance directly, which is to say controlling tone colour.

Overtones and harmonics

Related but not identical, and the terms are often used loosely.

An overtone is a component present in a normal sounding note, alongside all the others.

A harmonic, in violin technique, is a note produced by isolating one of those components, by touching the string lightly at a node point so that only that component sounds.

So harmonics are overtones made audible in isolation. Playing a natural harmonic at the string's midpoint isolates the first overtone, an octave above the fundamental.

Overtones and intonation

Two notes are in tune with each other when their overtones align.

An octave is in tune when the upper note's fundamental coincides exactly with the lower note's first overtone. A fifth is in tune when their overtones coincide at the appropriate points.

When they do not quite align, the near-coincident frequencies interfere and produce beating: a pulsing in the sound.

Listening for the elimination of beating is how string players tune fifths, and how double stops are tuned. It is more precise than comparing remembered pitches, because it is a physical phenomenon the ear detects readily.

Overtones and the temperament problem

Some overtones do not correspond to notes in equal temperament.

The seventh partial, for instance, is noticeably flatter than the equal-tempered minor seventh above the fundamental. The eleventh sits between two adjacent semitones.

This is why a chord tuned to pure intervals sounds different from the same chord on a piano, and why string players adjust intonation expressively rather than playing fixed equal-tempered pitches.

It is a real and audible phenomenon, not an academic point.

How it is taught

Rarely as a topic, frequently as an explanation.

When a student asks why bowing near the bridge sounds bright, the answer is overtones. When they ask why an in-tune note rings more, the answer is overtones. When they ask why two instruments sound different on the same note, the answer is overtones.

Teaching it once, with demonstration, makes several otherwise arbitrary-seeming techniques suddenly coherent.

The most convincing demonstration is playing a low open string and listening for the higher pitches within it, which most students have never noticed and can hear once told to listen.

Hearing them

Most students have never consciously heard an overtone, and the demonstration takes thirty seconds.

Play the open G string firmly and let it ring. Listen past the obvious pitch. With attention, higher tones become audible within it, particularly the octave and the twelfth.

Then play the harmonic at the midpoint of the same string. That pitch, isolated, is one of the components that was present in the full note.

Once a student has heard this, several other things stop being abstract: why bowing near the bridge sounds bright, why harmonics exist where they do, and why in-tune notes ring.

The temperament consequence

Some overtones do not match equal temperament, and this has a practical effect.

The seventh partial is noticeably flatter than the equal-tempered minor seventh. The fifth partial, a major third, is flatter than the equal-tempered major third by an audible amount.

This is why a string quartet playing a sustained chord will tune the third lower than a piano would, and why the chord sounds purer as a result.

Students notice this before anyone explains it, usually as confusion about why their teacher wants a note placed differently in a chord than in a scale.

Work on tone and sound production where somebody can hear the difference. We run private and group violin lessons in Alpharetta, Duluth, Berkeley Lake and Marietta. Call 470-789-2422 to talk it through, or book a no-commitment evaluation lesson.