High and Low Pitches

The mechanism of human pitch perception is different at low and high pitches:

• Fletcher's observations on pitch do not apply at very low frequencies and above 1000 Hz;
• Terhardt defines the crossover from virtual to spectral pitch to be at 800 Hz.

At very low frequencies, we may hear successive features of a waveform, so that it is not heard as having just one pitch.

• try pitchpartials.m at low 27.5

For frequencies above 1000 Hz, the pitch frequency is heard only when the fundamental is present.

• try pitchpartials.m

Fletcher proposed place theory for high pitches and a time mechanism for low frequencies.

There is no apparent discontinuity in the sensation as we play notes from lowest to highest pitches--two mechanisms overlap in frequency range.