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Just like Optical illusion happens to our eyes, can this happen to our ears?

Consider a well tuned piano. Can we make hearing illusion with music? I show an example with steps:

  1. Play a note (or specially chord) on high octaves
  2. Play a note or chord on lower octaves than previous one (in general)
  3. A second chord be heard like it have more pitch than previous chord. (but in general first chord was on higher octaves.)

When I said "in general", it means not all notes have to be lower or higher than other chord. Also two chords should not be too far from each other. I think only 1 or 2 octaves at most.

I feel like I heard it before like in Rachmaninoff Prelude Number 5 or Beethoven piano sonata no 32, first movement but I'm not sure if that's true or not.

Note that this kind of illusion happens to me not because of just playing two chords. I think the music makes the meaning and changes everything and it depends on sentences that were played moments ago. I think that's how it feels.

Looking at this line from Prelude Number 5 of Rachmaninoff.

enter image description here

As you can see the red parts have generally higher notes but when you play it, it seems that blue parts have higher pitch.

Also another kind of illusion (I wrote this part just to show the case):

enter image description here

I don't know what the word is to describe those blocks so I highlighted them in box.

After hearing blue boxes, the last note in red box (G3 I think) is like G4. Not a problem with pitch but because you heard G4 just a moment ago then G3 feels have the same meaning. But I think that's different from Rachmaninoff example.

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    Sorry, I don't what you are trying to describe in your question, but this site has good demonstrations of several audio illusions. deutsch.ucsd.edu/psychology/pages.php?i=201 – user19146 Aug 27 '15 at 21:29
  • Hi, I answered, but looking back I don't think it's what you're after. I don't think the other answer is either. – Some_Guy Aug 28 '15 at 8:37
  • Could you provide a snapshot of sheet music with an example of the notes played please, I'm interested to see what you mean :) – Some_Guy Aug 28 '15 at 8:37
  • @Some_Guy Thanks for the answers. it was interesting and ill do more research about it. anyways i updated my question with some example. sorry i couldn't find more. im sure ive heard more cases like this which was kind of weird for me. – M.kazem Akhgary Aug 28 '15 at 10:49
  • Every time I listen to the Lugansky version of that Rachmaninoff piece, I always hear the red- and blue-labelled with the proper relative pitches (i.e. red always sounds higher than blue). The few times I've tried it on the piano, the experience has been the same for me. – Dekkadeci Sep 12 '17 at 13:49
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Communicating in a language that is not your own can be very frustrating!

The answer is yes, and they are called combination tones

Some examples here

when certain pitches are tuned to just intonation (simple integer rations) they can interact and produce other simple ratio notes, ending up with chords that sound like they have more notes in than you are playing. I think this interaction is one of the reasons tambura and other drone instruments can sound so full

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    Not to mention that dastardly progression (which of course I can't find right now) where it sounds like the pitches are continuously going down, even tho' they aren't. – Carl Witthoft Aug 27 '15 at 23:44
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    do you mean descending shepard tones ? – Some_Guy Aug 28 '15 at 8:24
  • yep, that's it . en.wikipedia.org/wiki/Shepard_tone – Carl Witthoft Aug 28 '15 at 14:16
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Absolutely! Shepard-Risset tones sound as if they are continuously rising or falling; this is done by continously changing the overtone content of the sounds such that when the central perceived pitch has gone up or down an octave, the same tone an octave below (for ascending) or above (for descending)has faded in, and the same tone an octave above has faded out (for ascending) or in (for descending).

It is a very peculiar sensation to listen to a sound appear to descend for several minutes and still "feel" to be in the same octave. (I believe this is what Carl Witthoft was thinking of.)

  • Wonder if this works because of the interval between the notes, or just because as the higher tone fades out, one an octave lower fades in. Or did I miss something? – Tim Aug 28 '15 at 6:31
  • @tim It's sort of both. The second one is indeed how it's done, but I'm not sure the trick would work with any interval other than an octave. Definitely going to try in in audacity and see what happens though! – Some_Guy Aug 28 '15 at 8:24
  • Sounds like a b5 interval. – Tim Aug 28 '15 at 8:46
  • i think thats the reason. thanks for the answer. but i have to do more research. but can you look at the edit in question. maybe its something else – M.kazem Akhgary Aug 28 '15 at 10:56
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    I believe it's related. Note that there's octave doubling going on here as well, just like the Shepard-Risset tones use octave doubling, so you're going to have higher overtones reinforcing each other, and therefore a higher-sounding note. I am not an acoustician other than from messing around with synthesis, so I can't conclusively say this is why, but I'd bet it is. – Joe McMahon Aug 30 '15 at 1:05

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