Approximately speaking, what is the smallest temporal difference, expressed in milliseconds, in note lengths (for consecutively sounded notes) that an average, untrained listener can still (semi)consciously perceive? What order of magnitude are we talking about here? 10 ms? Or more like 50 ms?

In order to make the question a bit easier to answer, let us confine our attention to the following situation: a diatonic scale of quarter notes, played slightly legato on a concert grand, in a slow adagio-like tempo (60 BPM), and in a room without any noticeable reverb.

I'm trying to quantify the "infinitesimal" lengthening and shortening of notes going from one phrase to the next, but I find it difficult to come up with realistic numbers.

Edit: I'm not asking for the shortest perceivable note duration, but for the smallest perceivable difference in length between two consecutive notes.

  • 1
    I think the OP is going after stuff that's more like "How much shorter can a note be than the one immediately before it before we notice that the notes sound rushed". The edit is definitely leaning in that direction.
    – Dekkadeci
    Jul 29, 2018 at 6:59
  • It's not the length of the notes I think you want to ask about, I think you want ask what the smallest perceivable change in tempo is, which is more about changing the spacing of when the notes start, not how long they are. If you're really asking about how much music can speed up or slow down before listeners notice, please edit or comment confirming that. Jul 31, 2018 at 18:21
  • If we are talking about a series of changes then a slow accelerando would fit the bill and might give us a fairly low answer. If we are talking about just two notes of different lengths then it might be harder to observe
    – JimM
    Aug 12, 2018 at 11:38

2 Answers 2


This article on auditory time-interval perception suggests that the differences in perceivable time suffer from misestimations depending on the length of the sounds, such that shorter sounds suffer from greater degrees of misperception than longer ones, so the number of ms difference shifts as the overall note duration shifts.


I would assume that it definitely depends on the tempo. I think if the tempo is 120 bpm, the noticeable time-difference would be somewhat close to 2 times higher than the noticeable time-difference of a 60 bpm tempo. For example, if the noticeable time-difference for a 60 bpm tempo was 12 ms, then something like 6 ms would be noticeable for a 120 bpm.

I don't know what the values are, in fact I am searching for an anwser too. I found some articles here and there on a google search, here's what I found so far.

This study (https://www.google.com/url?sa=t&source=web&rct=j&url=https://pdfs.semanticscholar.org/8a8f/80588a0e40cba56018e53827a14e9af0d3a7.pdf&ved=2ahUKEwjXpcuc_5bnAhVvrlkKHQ25AD8QFjAKegQICRAB&usg=AOvVaw3plk6ahr-pTabhIEuOezB1&cshid=1579690523482) seems to suggest that a difference of 8% in the initial tempo is, on average, what's considered a noticeable time-difference. However, in this study, the speed at which the tempo is changing was constant. It was not a single-beat change in tempo that was tested, but a gradualy changing tempo.

I would assume that a more abrupt change in tempo is easier to notice than a gradualy changing one, but I haven't found any intel on this yet.

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