Phasex, or Phase Harmonic Advanced Synthesis EXperiment, developed by William Weston, is a virtual realtime software synthesizer for the linux platform, based on the concept of "phase offset modulation." (Demos above are with version 1:0.12.0+m1-6kxstudio1, available in the KXstudio repositories.) The GUI above shows the entire panel, although it can be displayed as two pages, with the oscillator section on the second page. It has both polyphonic and monophonic capabilities, and can be used as a plug-in or standalone.
Phasex includes 4 oscillators, each with a series of waveforms including bandlimited saw and square waves, triangle wave, sine and others. External audio input (such as a second synth, or soundfont player, sampler, etc.) can also be routed as input, modulated through the envelopes, and reproduced as MIDI inputs are received. AM, FM and PM capabilties are provided for each oscillator.
All four oscillators, as well as four LFOs, can provide bipolar and unipolar output. Transposition, detuning and pitch bend can be set independently for each oscillator. A filter section includes a variety of filter arrangements, such as LP, BP, HP, LP+BP, LP+HP. A "retro" filter option is available for each type.
Both amplitude and filter sections include traditional ADSR envelopes.
Chorus, delay and phased chorus effects are located in the lower lefthand area of the interface. Pan and stereo width controls are located on the left side of the GUI.
Ken Restivo's collection of patches for Phasex HERE. NB: Depending on the version you are using, these patches may or may not work.
An initial preset bank of my own, for starters, HERE. These presets were made using the current KXstudio version.