Why is the perfect fourth dissonant in some cases when it does not sound dissonant? When I play it in closed position, it does not sound dissonant at all. When I play it as a compound interval, I would kind of agree an extremely excessively tiny bit. Why is it considered a dissonance sometimes when it actually does not?

  • This might have the answer you want: music.stackexchange.com/questions/64984/… – Mirlan Mar 19 '19 at 5:39
  • Highly related: music.stackexchange.com/questions/67061/… – Dom Mar 19 '19 at 5:42
  • It will depend what instrument/tuning it gets played on. Give us a clue at least. – Tim Mar 19 '19 at 7:35
  • @Tim I think it's reasonable to assume 12-TET here, and I doubt the instrument would make a huge impact on its consonance. – user45266 Mar 20 '19 at 15:10
  • @Tim: It doesn't depend on the instrument except in artificial circumstances (no musical context) and with untrained listeners. What it really depends on is musical context. – Ben Crowell Mar 21 '19 at 1:52

Dissonance has no universal definition but depends on style and context.

For example, the perfect fourth is a dissonance in the context of species counterpoint. Whether it sounds pleasant, subjectively, is irrelevant: in that domain, it behaves as a dissonance, that must be resolved through falling by step. Again the everyday definition of dissonance is not involved here. In this context, the word dissonant indicates a tension function: the music cannot stop on this note, it must resolve according to the rules of the style.


The consonance of the Perfect Fourth, like all intervals, depends on context. In this video, there's a great example of perfect fourths sounding really dissonant.

Also, certain styles of music treat it different ways. Consonance and dissonance are largely context and culture related in nature, and though people have attempted to quantify them, they really can't be pinned down, other than the ubiquitous "it sounds like...".

  • The perceived dissonance of the fourth is, I believe, ultimately related to its nonexistence in the harmonic series upwards from the fundamental tone. It's first iteration is of course 3 to 4, and we naturally hear 4, the fundamental tone, as wanting to be at the bottom of the interval. But that's just my nerdy geometric opinion. – Scott Wallace Mar 20 '19 at 9:45
  • @ScottWallace Wow, I never considered that. I would upvote that as an answer! – user45266 Mar 20 '19 at 15:09
  • Nice answer, 45266! Compared to the tritone, m2, M2, m7, and M7, the P4 sounds very consonant to me. Also, that girl in the thumbnail looks nice. – user53472 Mar 22 '19 at 11:20

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