What's the shortest that a note can be and still have a recognisable pitch?

Question

While talking about this question: What does it mean to play a note for half a second? I got to thinking - how short can a note actually be for us to perceive its fundamental pitch?

Obviously real world notes often fade in at the start or have initial attacks that are somewhat 'noisy' and aperiodic. But I'm less interested in that aspect; I'm just wondering, given a note of stable pitch at a clearly audible volume, how long it takes us to recognise that pitch.

I'm sure there are a number of possible variables - harmonic spectrum (timbre) of the note and frequency are two obvious ones, and it is probably listener-dependent as well.

I'm more interested in how fast people can recognise pitch than in what a computer might be able to do.

Answer 1

Here is a very nice demonstration that shows the relationship between pitch perception and duration. Very short sounds are perceived as clicks, and it takes a minimum number of cycles for a pitch perception to arise.

How long must a tone be heard in order to have an identifiable pitch? Early experiments by Savart (1830) indicated that a sense of pitch develops after only two cycles. Very brief tones are described as "clicks," but as the tones lengthen, the clicks take on a sense of pitch which increases upon further lengthening.

It has been suggested that the dependence of pitch salience on duration follows; sort of "acoustic uncertainty principle" ,

Δf Δt = K,

where Δf is the uncertainty in frequency and Δt is the duration of a tone burst. K which can be as short as 0.1 (Majernik and Kaluzny, 1979), appears to depend upon intensity and amplitude envelope (Ronken, 1971). The actual pitch appears to have little or no dependence upon duration (Doughty and Garner, 1948; Rossing and Houtsma 1986). In this demonstration, we present tones of 300, 1000, and 3000 Hz in bursts of 1, 2 4, 8, 16, 32, 64, and 128 periods. How many periods are necessary to establish a sens of pitch?

To my ear, fewer cycles are needed to perceive a pitch in the demo in the 300 Hz sample than in the 3000 Hz sample.

Answer 2

One can easily distinguish a full major scale played in less than a second on a principally monophonic instrument like recorder (guitars and pianos don't count because they arpeggiate, letting a note ring on while the next already has an onset) from a minor scale.

So 10 notes per second, at least at treble recorder pitch, are no problem whatsoever.

As the instrument becomes lower in pitch, the speed with which notes are recognized decreases. Overtones help, so pure sinoid low notes are hardest for speedy pitch detection.

Answer 3

The answer to this is not absolute; it will vary according to the difference limen of the individual. This is the smallest change in a stimulus that the human brain can detect, however establishing a theoretical datum point for this is always going to be problematic and, in reality, the only meaningful data can be derived from experimentation.