Wiisp Drone Synth is a free software synthesizer developed by Akunull. Available format(s): stand alone application for Android.
Wiisp is a simple drone synth. Oscillators are sine waves with adjustable pitch. The second oscillator has a higher pitch limit. Both are directed to a delay, with optional fm from oscillator A. LPF is a resonant lowpass filter that is bypassed whenever the slider is set to 0. The filter has fm input from each of the oscillators. Glide creates a smooth transition between changing any of the values. Higher glide, longer transition.
The audio engine is open source and the PureData patch is available at thiiird.com/wiisp