The Shepard Tone

**Sesquipedalian** · 10-26-2011 11:42 PM

This is a video demonstrating the "Shepard tone" a sound that seems to rise or fall endlessly, even though in reality it's not going anywhere. I think it could have uses in this community, or even for hypnosis. The tone can go on for as long as you want, but it will still seem to rise or fall in pitch. This one happens to sound like airplanes.

Discuss.

**tommo** · 10-27-2011 12:13 PM

It certainly does get deeper. Or one of the sounds gets made louder than the other sounds. The droning noise goes over the more motor-y noise toward the end. Plus the whole thing gets louder.
Just listen to the end and skip back to the beginning.

**Zhaylin** · 10-27-2011 02:24 PM

I'm going to have to listen to this several more times.
Does anyone else notice the extremely high pitched and sort of pulsating sound that rides on top of the whole thing? I didn't notice it the first time I listened. The first time I listened it seemed I could zone in on one tone while a second sort of weaved throughout to create the illusion (?).
I turned my speakers up just a little and tried to concentrate more on separating the sounds, but the high pitch pulse was too distracting.

**khh** · 10-27-2011 02:49 PM

Yeah, these tones are cool. I sat down in the wrong room once, and got a complete lecture on them. It was quite interesting, but I have of course forgotten what I learned by now.

**Ne-yo** · 10-27-2011 03:23 PM

Yea this sounds like a change in pitch due to a shift in frequency on the sound waves, pretty much exactly like the the Doppler Effect when you hear a siren approach you the pitch in frequency is high and once it moves away the pitch in frequency is lower.

**Sesquipedalian** · 10-27-2011 06:15 PM

Well, it's not exactly the doppler effect. The doppler effect applies to sounds coming from a moving source in a fluid. The Shepard tone can sound somewhat like it, but really its just a glissando (like bowing a violin and sliding your finger up or down the string.) This glissando is stacked and fades in and out so you have at least 2 tones at the same time that cover for the third that is jumping back to its starting pitch. Thus, it slips away undetected and the sound continues to 'fall'. This is one of the better ones out there, except for one tone that is different from the others. It makes it easier to figure out how it works.

**Ne-yo** · 10-27-2011 06:58 PM

Ah I see, yea they seemed similar to me in audio, however after further research it appears that pitch circularity(Shepherds tone) is an auditory illusion whereas the Doppler affect is a real phenomenon. Good stuff, I like learning new things, thanks.

**ThePreserver** · 10-29-2011 04:22 AM

I love Shepard Tones! They're like the Penrose Stairs of sound

Now imagine if you were on a two-story airplane, the staircase was Penrose, and the sound of the engines was a Shepard Tone? That's what I call a trippy dream.