Syntonie - Isohélie

Syntonie's Isohélie is a posterization effect, with three channels for video synthesis in Eurorack. Posterization refers to the effect of tone separation and tone reduction.

The Isohélie module offers three channels that are based around a 3-bit ADC/DAC. These will quantize the input signal into 8 equal steps, resulting in 8 different color shades. Processing a full RGB signal with the 3 channels will constrain it to 512 possible colors.

The bitswap feature allows to swap the 3 bits together before they’re summed by the R2R DAC, which results in a colorization effect and can be controlled up to video rate.

All 3 signal inputs and CV inputs are normalized.

Where does the name come from? Isohélie is a term used in french versions of graphic editing softwares to describe posterization, it is formed on ancient Greek “iso” meaning equal and “hêlios” meaning sun/light.

Inputs:

• 0-1V IN, 499 ohm
• 0-1V CV, 499 ohm

Outputs:

• 0-1V Bitswap, 499 ohm
• 0-1V OUT, 499 ohm