-Experience the "illusion"-
There are many visual "optical illusion" works, but it is hard to experience the "auditory illusion".
"INFINITE SWEEP SYNTHESIZER" (hereinafter "INFINITE SWEEP") is an application that can easily reproduce "Infinite Continuous Scale" which is one of "illusions" and create various sounds.
Recommended for live music, recording, meditation, etc.
[What is "Infinite Continuous Scale" ?]
The frequency of sound that can be recognized by humans is said to be approximately 20Hz to 20,000Hz (20kHz).
Also, the sound that a person recognizes is recognized as "the same sound one octave above the original sound" when the frequency doubles.
For example, when the 440Hz sound (A) becomes 880Hz, it becomes "1 octave higher sound (A)".
The Infinite Continuous Scale was discovered by US cognitive scientist Dr. Roger Shepard as an “acoustic illusion” that utilizes these properties.
The Infinite Continuous Scale was named by him as "Shepard tone".
After that, various researchers and artists announced variations of Infinite Continuous Scale.
However, they all needed to be made in a recording studio, or have a special music production environment and equipment.
[Easy infinite scale and new experience]
There are many things that you can experience a mysterious sensation by visual illusion, but We developed this "INFINITE SWEEP" because We wanted to experience the Infinite Continuous Scale,
more easily.
[function]
"INFINITE SWEEP" has preset tones, so you can immediately enjoy various infinite scales.
"PLAY / STOP button"
It is a big button that stands out most. If you press this, the infinite scale starts immediately.
"FREEZE button"
This is a "freeze" button that cannot be reproduced with sampled or recorded infinite scale sounds.
You can freeze it at any position, or you can freeze it at a specified pitch.
"Speed volume"
The speed of the infinite scale can be changed.
If its too early, it may sound like a siren.
The numerical value that can be set with the speed volume sets the time for which the pitch rises one octave.
It is recommended that you set it slowly and change it over 20 to 30 seconds.
"Step Volume"
It has a continuous and smooth pitch change, but you can also listen to it in a staircase scale.
The pitch changes with the step set by the speed volume divided by the number set by this step volume.
You can also try other strange scales (eg 21 scale, etc.) other than the familiar "12 scale".
"UP / DOWN button"
You can switch between rising and falling of the infinite scale.
"Accelerometer mode"
You can switch to "accelerometer mode" from the "red-blue-green" arrow button at the top right of the screen.
By tilting your device, you can control the speed of an infinite scale, and if you hold it upside down, you can descend.
It is to be usable even for a bitly performance.
[Pursuit of Infinite Continuous Scale]
If you are familiar with synthesizers, you can dig deeper to create finer sounds.
INFINITE SWEEP uses 32 oscillators.
Main oscillator group (16 oscillators) called "main sweep generator",
It consists of a "reverse sweep generator" (16 oscillators) that operates in the opposite direction.
The main sweep generator is
・ Basic oscillator waveform change (BASIC / FM)
・ Subharmonic setting (0 to 11 semitones)
・ Low-pass filter
・ Flanger
・ Delay
・ Auto pan
・ Reverb
It is possible to make sounds and adjust effects.
(The basic waveform of the reverse sweep generator is fixed to a sine wave)
[Control via Bluetooth MIDI]
If you have a Bluetooth MIDI compatible keyboard or adapter, an application that can output MIDI via smartphone Bluetooth,
You can control "INFINITE SWEEP" from them.
It is also possible to specify the "start note" that was difficult to capture on the main unit due to the user interface.
It can be used for live performances and recordings.