Forget optical illusions, here's an audio illusion!

[Steam]

Play this video once, then again and again. It seems to get higher in tone every time. But that's impossible because it's the same video!
Mad weird.

[fireball]

weird didnt work for me...

[Usarka]

out of it. worked for me. wheres my axe...

[jrandom]

The tone *is* in fact continually creeping up, inasmuch as each note contains a number of harmonics across the audible spectrum. With each step, the harmonics 'wrap around' back to the lower end, so at each point there's always a lower tone moving to a higher tone, even between the last note in the sequence and the first one.

If anyone's particularly interested, Google yourself some free spectrum analyser software that shows in real time what's playing on your computer's sound card, run it while listening, and you'll get a visual representation of what I describe.

[EJK]

I can't hear it....
oh, the speaker was in mute lol

[deanohit]

huh, thats pretty cool. Got it the 2nd time I played it and the tone went up, but when I played it a 3rd time, it just sounded the same again.

[Tank]

The tone *is* in fact continually creeping up, inasmuch as each note contains a number of harmonics across the audible spectrum. With each step, the harmonics 'wrap around' back to the lower end, so at each point there's always a lower tone moving to a higher tone, even between the last note in the sequence and the first one.

If anyone's particularly interested, Google yourself some free spectrum analyser software that shows in real time what's playing on your computer's sound card, run it while listening, and you'll get a visual representation of what I describe.

Wot he said

[xwhatsit]

The tone *is* in fact continually creeping up, inasmuch as each note contains a number of harmonics across the audible spectrum. With each step, the harmonics 'wrap around' back to the lower end, so at each point there's always a lower tone moving to a higher tone, even between the last note in the sequence and the first one.

If anyone's particularly interested, Google yourself some free spectrum analyser software that shows in real time what's playing on your computer's sound card, run it while listening, and you'll get a visual representation of what I describe.

Spot on. That's in fact how those electric organs work -- it's not a single tone or waveform, but many (relatively) pure waveforms at different pitches combined. Think of each organ note, just one note pressed on the keyboard, as actually playing a chord. It's sort of a clumsy approximation of real instruments, which are highly complicated waveforms with lots of harmonics (I play French Horn, which has a very rich set of harmonics and overtones, it confuses those electronic tuners to no end), except it's done so primitively you can get effects like this.

In this case, part of the organ tone-set is a harmonic one, two octaves up from the root note. In addition, there's a few others -- can't tell much from these shitty laptop speakers, but it sounds like a tone one fifth from the root is there as well.

A spectrum analyser is one way, or you can have a play yourself -- plenty of audio software on the net that lets you simulate organs and stuff. Most emulate the same interface you get on the old organs -- a series of `stops' that you can turn on and off to add more tones to the root. A single organ tone on it's own won't actually sound like an organ, you'll think it sounds very bland.

[Mikkel]

The tone *is* in fact continually creeping up, inasmuch as each note contains a number of harmonics across the audible spectrum. With each step, the harmonics 'wrap around' back to the lower end, so at each point there's always a lower tone moving to a higher tone, even between the last note in the sequence and the first one.

If anyone's particularly interested, Google yourself some free spectrum analyser software that shows in real time what's playing on your computer's sound card, run it while listening, and you'll get a visual representation of what I describe.

*nodnod*

First thing I noticed was that it wasn't a single sinus note but a harmonic construction. Providing such an indepth description though... good job

[Maha]

weird didnt work for me...

But kept you busy tho aye?.....

[fireball]

But kept you busy tho aye?.....

for all of hmm 2 cycles of that music that hurt my ears