Re: Shepard tone

[Per Boysen <perboysen@gmail.com>]

I'm afraid I don't know about that, Daryl. But when you have time,  
try it out with a looper set to overdub. Play slide guitar glissando  
and fade in each new start with a volume pedal/knob. Try all  
combinations of octaves and numbers of layers. After an hour you will  
know everything about Guitar Shepard Looping and tell the list about  
the tricks.

per

On 9 nov 2007, at 16.29, Daryl Shawn wrote:

> Per, thanks for this, I missed this on the Wiki page. I'm working  
> it out on guitar, but am not convinced it really creates the same  
> illusion, possibly because there are only so many octaves to work  
> with. In the example below, do you have any idea if the instruments  
> are spread so far apart that no instrument ever crosses into the  
> other's octave? I'm going to try to record my version this weekend.
>
> and Qua, thanks for the Exploratium link. I visited the museum a  
> number of years ago and vaguely remember the round  
> keyboards...super cool.
>
> Daryl Shawn
> www.swanwelder.com
> www.chinapaintingmusic.com
>>> Very interesting! At http://en.wikipedia.org/wiki/Shepard_tone I  
>>> found
>>>> consider a brass trio consisting of a trumpet, a horn, and a  
>>>> tuba. They all start to play a repeating C scale (C-D-E-F-G-A-B- 
>>>> C) in their respective ranges, i.e. they all start playing C's,  
>>>> but their notes are all in different octaves. When they reach  
>>>> the G of the scale, the trumpet drops down an octave, but the  
>>>> horn and tuba continue climbing. They're all still playing the  
>>>> same pitch class, but at different octaves. When they reach the  
>>>> B, the horn similarly drops down an octave, but the trumpet and  
>>>> tuba continue to climb, and when they get to what would be the  
>>>> second D of the scale, the tuba drops down to repeat the last  
>>>> seven notes of the scale. So no instrument ever exceeds an  
>>>> octave range, and essentially keeps playing the exact same seven  
>>>> notes over and over again. But because two of the instruments  
>>>> are always "covering" the one that drops down an octave, it  
>>>> seems that the scale never stops rising.
>