Question 1

What is the harmonic series?

Accepted Answer

The harmonic series is the sequence of frequencies that vibrate together when a string, air column or other resonating body produces a sustained pitch. Each frequency in the sequence is an integer multiple of the lowest one (the fundamental). The trainer covers partials 1 to 16, with 1 to 12 as the core memorisation range used by composers and orchestrators.

Question 2

Why are partials 7, 11 and 13 not standard piano notes?

Accepted Answer

Equal temperament splits the octave into 12 equal semitones. The naturally-occurring partials 7, 11 and 13 fall between those steps: partial 7 is about 31 cents flat of the nearest tempered note, partial 11 sits roughly halfway between two semitones, and partial 13 is about 41 cents sharp. The trainer flags them as non-tempered or ambiguous and plays them at their exact ratio-based frequencies, never as ordinary piano notes.

Question 3

Why do composers and orchestrators learn the harmonic series?

Accepted Answer

Almost every acoustic instrument produces its pitches by exciting some form of the harmonic series — brass through lip vibration on a tube, strings through bowing or plucking, woodwinds through reeds and air columns. Understanding which partials sound easily, which are problematic and how they relate to the fundamental is essential for writing idiomatic brass parts, calling for natural harmonics on strings, designing spectra in electroacoustic work, and predicting how chords will ring in a hall.

Harmonic Series Trainer