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.

  • Is this a duplicate: sound.stackexchange.com/q/28163/7016 – Doktor Mayhem Apr 27 '15 at 7:10
  • @DrMayhem Not really - that's about the shortest perceptible sound, and not about perception of pitch (as the demo linked to in Alan Munn's answer below shows, you need longer to perceive a pitch than to just perceive a sound). Some of the answers may have relevant info though. – topo Reinstate Monica Apr 27 '15 at 7:32
  • OK - it just rang bells so I thought I should mention it – Doktor Mayhem Apr 27 '15 at 7:38

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.

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    Using small laptop speakers, to me 4 cycles seems to be the threshold, with 8 cycles being much more clearer. – Von Huffman Apr 26 '15 at 16:33
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    Seems to be 8 for me at 300 and 3000, and 4 at 1000. I'm going to get drunk and then try it again... – topo Reinstate Monica Apr 26 '15 at 18:31
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    For me it was 4/4/8 for the threshold and 16 all around before it stopped sounding significantly clearer. – Dan Is Fiddling By Firelight Apr 26 '15 at 22:12
  • I wonder if the reason why the 3000Hz sound tends to need more cycles to be recognized is because it overlaps with the "click" frequency. In other words, they mask each other. The click is there for all sustain times, because of the fast attack of the sound. Maybe the cycles would be somewhat constant if we reduce the click by increasing the attack (a little, by 2 to 10 milliseconds) and/or apply a low pass filter? – Von Huffman Apr 27 '15 at 1:28
  • @AlanMunn it seems clear that fewer cycles are needed to reveal the tone at lower frequency because cycles last longer at lower frequency. Makes me suspect the cited papers (1948, 1986) defined "duration" in seconds rather than cycles. – commonhare Apr 27 '15 at 13:05

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.

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  • Guitars and pianos are not the same as harps - the duration of their notes can be easily controlled. Regarding your last statement, I would say the same thing also occurs as you approach the other end of the spectrum; a piccolo or xylophone in the highest registers would be difficult to differentiate pitch. – jjmusicnotes Apr 26 '15 at 13:46

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.

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    Sure, as stated in the question clearly there will be variables; I'm not looking for a single number! Data from experimentation may be exactly what I'm looking for, if you have any... – topo Reinstate Monica Apr 26 '15 at 13:39
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    The downvotes are most likely because you ought to provide links to experiment reports rather than just saying experiments need to be done. – Carl Witthoft Apr 26 '15 at 19:12
  • I used to be involved in psychology but I'm not any more. The only experimental data I'm aware of involves studies in inharmonicity. However it's possible that Bernard Richardson of Cardiff University will have done some work on this, although his focus is on acoustic physics rather than perceptual psychology. Perhaps this would be worth you pursuing as a doctorate? – Octave Doctor Apr 27 '15 at 14:34

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