phasex. PHASEX is an experimental MIDI softsynth for Linux/ALSA/JACK with a synth engine built around flexible phase modulation and flexible oscillator/LFO sources. Modulations include AM, FM, offset PM, and wave select. PHASEX comes equipped with multiple filter types and modes, a stereo crossover delay and chorus with phaser, ADSR envelopes for amplifier and filter, realtime audio input processing capabilities, and more.