Endless Series v3 - demo video 1: introduction to circular pitch illusions

First video in a three part set demonstrating the Endless Series version 3 VST/VST3/AudioUnit & RTAS Plugin. In this video the robot introduces the concept of the Shepard tone, and talks about where it has been used. He creates a shepard tone using midi and the operator synthesiser in ableton live, showing the laborious way to do it (not using Endless Series).

TEXT:

This is part one in a set of demonstration videos for endless series version three - a new Audiounit and VST plugin available on windows and mac os.
The plugin is based on the Shepard tone which is an auditory illusion that fools the ear into hearing a continuously ascending or descending scale, and is named after Roger Shepard who discovered it in thee 1960s.

The Shepard tone has been likened to the Penrose staircase visual illusion, used in the art of MC Escher, and more recently in the imagery of the blockbuster movie Inception. It's also sometimes likened to a barber pole, which is another visual illusion of continual motion in one direction. In music the Shephard tone has been used by many people - famously computer music pioneers James Tenney and Jean-Claude Risset, but also rock bands such as Pink Floyd and Queen, and modern electronic artists. Similar effects have also been noticed in classical music and even computer games.

The same principles have been used for sound effects in the Batman movie "The Dark Knight".

Traditionally in computer music Shepard tones are created using additive synthesis. On each step of a chromatic scale we generate a tone comprised of pure sine wave partials spaced at octave intervals. The amplitude of each sine wave partial is adjusted on each semitone step so that it fades in at the low end and fades out at the high end of the frequency spectrum. The listener hears a scale with twelve different pitches, but the octave of the pitch is ambiguous due to the shifting amplitudes of the partials. Usually five or more partials are required to produce a convincing illusion.

To demonstrate the Shepard tone concept and the basic principles behind how endless series works I have created a Shepard tone using midi in ableton live.
There are 8 instances of the operator synthesiser on separate channels and each one is set to the default sine wave sound. Each of these will produce the sound for one partial. On each track i have made a midi clip that contains an eight octave chromatic scale. If you look at the velocity of the midi notes, you will see that the amplitude follows a bell shaped curve as the scale traverses the 8 octaves.

Let's listen to one partial on it's own...

The difference between the midi clip on each of the eight operator tracks is that they are offset in phase, in such a way that each instance of operator is playing a note an octave above the previous instance. Notice that they are still following the same bell shape amplitude envelope as the scale is traversed.

Now let's listen to all the partials together...

When the speed of the scale is increased it is much easier to hear the pattern repeating, but at slower speeds, especially when heard with other sounds, the illusion can be quite effective.

Clearly the process of creating Shepard tones like this is very laborious! Fortunately Endless Series does all of this for you, and has a lot of options to produce much more interesting sounds. In part two I'll explain the main parameters of the plugin and introduce the tone generator section. In part three I'll show you the other effect modes, which open up even more possibilities, allowing you to process audio with a circular pitch ring mod, phaser, filter and flanger.

Category:

Music

Tags:

• shepard tone
• illusion
• paradox
• penrose
• stairs
• scale
• sheperd
• Endless Series
• risset tone
• endless stairs
• endless staircase
• ableton live
• vst
• audiounit
• circular pitch
• synthesizer

[olilarkin]

what's the problem? if you are not hearing any sound then probably you need to insert an audio file on that track or record enable the track. some hosts will mute the plugin when there is no audio (logic and dp i think).

[MarcPopeTV]

seriously, nice video but i really hate it when people use those annoying computer generated voices. a person clearly made this video, can that person not talk?

[metemi]

I just got the demo version, looking fwd. to the other 2 tutorial videos. I can't figure out what the point of the first 24 presets are for, are they meant to be used by themselves?

[whoddaya]

@MarcPopeTV The person probably wasn't too stupid with this level of expertise, then, to do the voice this way. Who are we to understand why he did it the way it is done? :)

[MarcPopeTV]

@whoddaya acceptable in most cases but not when the topic being discussed is "audio" and most especially not when it is something as complex as circular pitch illusions. i'm sure someone with the level of expertise required to explain this could have got his/her hands on a microphone :)

[whoddaya]

@MarcPopeTV That person probably doesn't have a mic.

[EnricoCosimi]

great fun, inspiring and fascinating video!!! I cannot wait for part 2 and 3!!!

[djsangeet]

thanks, will try your plug in today :)