So does this mean there were some Fourier transform involved? If some steps were raised or lower, made thinner or wider, would it produce a different sound? You could technically make any sound wave using Fourier transform like with music synthesizers. Is that what is happening here but with a clap sound? Could it be done with other sound instead of a clap? Could some sound be easier to transform than other into certain sound or some limitation to what the sound could be? If instead of 91 clap echoes but 1000 echoes and if you slow it down and change the pitch or frequency of those individual clap sounds, you can make it sound like some other sound wave. That is what I'm guessing you can do. The simulated sound in the video sound like a low quality version of a sound wave (bird chirp).
What physically happens here is a convolution of clap sound and the impulse response of the pyramid reflection. Then you can apply that knowledge however you'd like.
Hi! Very interesting video on a really surprising effect! I have a few questions related to this: 1) You are saying that wave diffraction is happening here : to what extent would this affect the phenomenon? 2) The 2D geometrical analysis you made was really convincing! I am surprised that the length of the steps doesn't influence the phenomenon : would a 3D-consideration change anything on the results? I mean, if you used a really small length of the steps, but the same height and depth as the pyramid, would it give the same results in situ ? 3) After watching your video, I noticed it was possible to produce the same effect on a large construction site fence (with small "steps" of 3 cm), but not on a small staircase of roughly 90 steps (1 cm for height and depth). Since both structures are really thin, would acoustic impedance have a role in this effect ? Thanks by advance if you can help me understand this !
Glad you found it useful! To answer your questions: 1) diffraction serves to disperse the reflected sound wave so that you can hear the echos from where you are standing. Without diffraction, the sound will reflect off the higher stairs and simply go up and away from you and you won't hear it. 2) Length of steps very much matters. For sake of simplicity I'm only talking about the case where step height = step length/depth. 3-D model WILL CHANGE things to a certain extent, mostly in the "color" of the sound, but the basic idea is the same. 3) This effect is akin to diffraction grating in optics, so with different step size you get different frequencies. at step size of 3cm, the frequency you hear is about 5.7kHz, that is VERY HIGH frequency! At 1cm step size, the frequency is now 17kHz! Most people cannot hear this frequency clearly. I know I totally cannot, proven with experiment. Hopefully this helps!
@@werewolfwu Thanks a lot for your really clear answers! I'm sorry for wasting you time, other questions are coming to my mind : 1) For example, would it be possible to emit other sounds, like a monofrequency signal ? Because based on the geometrical model, the gliding pitch effect would still occur... but I have a feeling such a thing wouldn't happen in situ (if so, why ?) 2) Does the duration of the signal have an importance ? Or do you think interferences would happen if it is too long ? 3) And are you planning to do a video to explain diffraction effects on this pyramid? The explanation you gave was really nice and I would be pleased to learn more about it applied to this context!
Glad you like the answers! 1) yes, it is totally possible, as long as you have the right geometrical shape. 2) the duration of the incident signal is important (short, ideally a pulse, hence clapping sound is ideal) for ease of analysis if you are trying to use echos to emulate something (like a bird). The duration of the echo signal is important for human perception, meaning if it is too short it cannot be perceived. 3) that seems to be a topic that is too esoteric to be made into a video at least for now. There are a lot of other interesting things to talk about in this world.
Thank you Werewolf, I have a question, if I wanted an echo with a constant frequency, could I just gradually change (slightly reduce) the length of the steps as I build higher ? Thank you and my best regards from France.
Interesting, but if it is like you say, a simple echo and because of the number of stairs, why can't it be heard the sound in the four sides? and you can say, maybe because the thing it has on the top... which is strange because it is heard the same sound on two sides ....
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Wow what an informative video, veeeery indepth. You are a great himan 😊
Glad you find it useful!
So interesting, thank you for explaining! 😊
My pleasure!
So does this mean there were some Fourier transform involved? If some steps were raised or lower, made thinner or wider, would it produce a different sound? You could technically make any sound wave using Fourier transform like with music synthesizers. Is that what is happening here but with a clap sound? Could it be done with other sound instead of a clap? Could some sound be easier to transform than other into certain sound or some limitation to what the sound could be?
If instead of 91 clap echoes but 1000 echoes and if you slow it down and change the pitch or frequency of those individual clap sounds, you can make it sound like some other sound wave. That is what I'm guessing you can do. The simulated sound in the video sound like a low quality version of a sound wave (bird chirp).
What physically happens here is a convolution of clap sound and the impulse response of the pyramid reflection. Then you can apply that knowledge however you'd like.
Great video!
Thank you! Glad you find it useful!
Thanks
You are very welcome!
Then why the pyramids in Egypt does not produce any sound ?🤔
For that we need to ask the Pharaohs.
Hi! Very interesting video on a really surprising effect!
I have a few questions related to this:
1) You are saying that wave diffraction is happening here : to what extent would this affect the phenomenon?
2) The 2D geometrical analysis you made was really convincing! I am surprised that the length of the steps doesn't influence the phenomenon : would a 3D-consideration change anything on the results? I mean, if you used a really small length of the steps, but the same height and depth as the pyramid, would it give the same results in situ ?
3) After watching your video, I noticed it was possible to produce the same effect on a large construction site fence (with small "steps" of 3 cm), but not on a small staircase of roughly 90 steps (1 cm for height and depth). Since both structures are really thin, would acoustic impedance have a role in this effect ?
Thanks by advance if you can help me understand this !
Glad you found it useful!
To answer your questions:
1) diffraction serves to disperse the reflected sound wave so that you can hear the echos from where you are standing. Without diffraction, the sound will reflect off the higher stairs and simply go up and away from you and you won't hear it.
2) Length of steps very much matters. For sake of simplicity I'm only talking about the case where step height = step length/depth. 3-D model WILL CHANGE things to a certain extent, mostly in the "color" of the sound, but the basic idea is the same.
3) This effect is akin to diffraction grating in optics, so with different step size you get different frequencies. at step size of 3cm, the frequency you hear is about 5.7kHz, that is VERY HIGH frequency! At 1cm step size, the frequency is now 17kHz! Most people cannot hear this frequency clearly. I know I totally cannot, proven with experiment. Hopefully this helps!
@@werewolfwu Thanks a lot for your really clear answers!
I'm sorry for wasting you time, other questions are coming to my mind :
1) For example, would it be possible to emit other sounds, like a monofrequency signal ? Because based on the geometrical model, the gliding pitch effect would still occur... but I have a feeling such a thing wouldn't happen in situ (if so, why ?)
2) Does the duration of the signal have an importance ? Or do you think interferences would happen if it is too long ?
3) And are you planning to do a video to explain diffraction effects on this pyramid? The explanation you gave was really nice and I would be pleased to learn more about it applied to this context!
Glad you like the answers!
1) yes, it is totally possible, as long as you have the right geometrical shape.
2) the duration of the incident signal is important (short, ideally a pulse, hence clapping sound is ideal) for ease of analysis if you are trying to use echos to emulate something (like a bird). The duration of the echo signal is important for human perception, meaning if it is too short it cannot be perceived.
3) that seems to be a topic that is too esoteric to be made into a video at least for now. There are a lot of other interesting things to talk about in this world.
Thank you Werewolf,
I have a question, if I wanted an echo with a constant frequency, could I just gradually change (slightly reduce) the length of the steps as I build higher ?
Thank you and my best regards from France.
That would be one way to do it. It'll be quite expensive though so better to keep it as a curious mental exercise.
@@werewolfwu Thank you.
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Werewolf Wu face reveal 😮
LOL! That is decidedly NOT what this video is about :-)
Our tour guide said it was to sound like a certain bird that Mayans thought looked like a feathered serpent, Kulkukan. He was of Mayan descent.
That's what I have heard too.
Interesting, but if it is like you say, a simple echo and because of the number of stairs, why can't it be heard the sound in the four sides? and you can say, maybe because the thing it has on the top... which is strange because it is heard the same sound on two sides ....
Anything is possible. This is just one theory. There are of course other theories too.