In my blog “What happens when we make a sound” I state “When we produce sound, the airstream passes between the two vocal folds that have come together. These folds are soft and are set into vibration by the passing airstream, think of when you blew through grass as a child. They vibrate very fast from 100 to 3000 times per second, depending on the pitch of the sound we make. However many times per second the vocal cords vibrate is the pitch sung, e.g. 100 times per second is 100Hz.” but this isn’t the whole story.
The vocal folds and therefore the air actually vibrate at multiple frequencies at once. These faster vibrations are called Harmonics or Overtones and along with formants (blog to come) are part of what determines your tone. You may have come across the idea of overtone singing before with people like Avi Kaplan from the Pentatonix, in which a harmonic is boosted to produce the effect of two notes being sung at once. Listen to a fantastic example of overtone singing below.
Everything in nature has harmonics and vibrate at multiple pitches at once. The only way to produce a sound without harmonics is with a tuning fork or an electronic synthesiser.
WHAT DO WE MEAN BY THE FUNDAMENTAL PITCH?
When talking about harmonics, you will often hear the term fundamental pitch. This means the original, lowest and strongest vibration. The is the one that we name the pitch that we are singing.
HARMONICS VS FORMANTS
You may have come across the term formants and wondered how they differ from harmonics. Harmonics come from the vocal cords and formants are formed in the vocal tract. Therefore you change the harmonics by changing the shape the of vocal folds and the formants by changing the shape of the vocal tract.
HARMONIC SERIES
If the original vibration (fundamental pitch) and vocal folds vibrate in a periodic pattern, then the higher vibrations will be at predictable frequencies.
The 2nd harmonic will vibrate twice as fast as the fundamental pitch.
The 3rd harmonic will vibrate three times as fast as the fundamental pitch etc.…
If the fundamental pitch were 100 Hz, the vocal folds would create all the harmonics below as displayed on the staff.
Fundamental Pitch: C2 or 65 Hz.
Second Harmonic: An octave above the fundamental pitch. It vibrates twice as fast as the fundamental pitch. C3 or 130 Hz.
Third harmonic: An octave and a fifth above the fundamental pitch. It vibrates three times as fast as the fundamental pitch. G3 or 195 Hz.
Fourth harmonic: Two octaves above the fundamental pitch. It vibrates four times as fast as the fundamental pitch. C4 or 261 Hz.
And so on.
When a person sings a C2, they are actually creating all these notes at once. However the higher the harmonic, the quieter the volume. Alone without the resonating tract, the higher harmonics can barely be heard. This is where the resonating tracks and formants come in. But I’ll save that for another blog.
IF YOU HAVE ANY QUESTIONS PLEASE GET IN TOUCH OR BOOK A LESSON HERE.
SINGING LESSONS WITH BETH ARE AVAILABLE IN PLUMSTEAD, LONDON OR ONLINE VIA SKYPE.
References:
Voice Science Works: https://www.voicescienceworks.org/
Practical Vocal Acoustics: https://www.amazon.co.uk/Practical-Vocal-Acoustics-Pedagogic-Applications/dp/157647240X/ref=sr_1_1?ie=UTF8&qid=1538584105&sr=8-1&keywords=kenneth+bozeman
