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Y A M - Yet Another Mutation

This is a project for an alternative firmware for Ambika, a hybrid MIDI polysynth and voicecard host from Mutable Instruments. 

Here's a short summary of changes _compared_ to official Ambika firmware:

* PolyBlep implementations replace the original band-limited 'saw' and 'square' oscillators for higher fidelity and less memory footprint (Polyblep implementation inspired by, but less general than, Emilies prototype for STM). 

* 'square' is now a Polyblep oscillator with more proper sounding PWM, i.e. more edginess, and no loudness drop for PWM modulation parameter above 0. 

* 'saw' is now a Polyblep oscillator (without any high pass pre-filtering and the modulation is different). The parameter for saw now add mix of a 2nd saw edge, resulting in a saw with sub oscillator (actually super oscillator) sound. 

* 'triangle' is no longer band-limited (to reduce memory footprint) and is folded (instead of clipped) upon modulation. 

* Added a quad PWM oscillator ('qpwm') very similar to the quad saw ('pad'). The modulation parameter simultaneously affects both detuning of the four pwm oscillators and the pulse width.

* Added an alternative FM oscillator ('fmfb') with feedback modulation. Just as for the regular FM oscillator, the modulation parameter defines the FM amount, but for modulation values above 64 increasing amount of feedback is added. At moderate levels the feedback adds 'grit'. At higher settings it adds digital distortion (deliberately left in).

* Added a 'csaw' Polyblep oscillator rather similar to the CS-80 inspired saw oscillator for Braids. Without modulation it's a plain saw (identical to 'saw'). Modulation adds a 'notch' discontinuity before the ramp.

* Added a 'vowel 2' oscillator that is identical to the regular vowel oscillator but without the phase noise.

* Ported phase57 mods for velocity and keyboard tracking to filter page and CC & NRPN assignments (104 and 105 respectively). Also, the active editing parameter is displayed in all uppercase characters. (http://blog.phase57.com/index.php/ambika/code for more details.) 

NOTES ON PATCH (PROGRAM) COMPATIBILITY with official Ambika firmware: 
Due to qualitative differences of the 'saw' and 'square' oscillators etc, levels may have to be adjusted somewhat to mimic original patches. If you really miss the original saw oscillator from the official firmware, this one is still available as 'oldsaw' (it's high-pass sampled and have a different character). In order to maximize patch (actually program) backwards compatibility, the added oscillators are put at the end of the oscillator selection (even though this means fmfb is not next to fm etc).

This repository was originally a copy of the Mutable Instruments GitHub Ambika repository at https://github.com/pichenettes/ambika
 
Original developer: Emilie Gillet ([email protected])

The firmware is released under a GPL3.0 license. It includes a variant of the formant synthesis algorithm used in Peter Knight's Cantarino speech synthesizer.

The PCB layouts and schematics, documentation, analyses, simulations and 3D models are released under a Creative Commons cc-by-sa 3.0 license.