Contralogic Productions has released Feldspar, a virtual analog synthesizer VSTi for Windows featuring a range of tempo-based modulation options.

Features:

• 16 LFO waveforms.
• Ring modulator with 18 algorithms.
• Tempo-synced delay with high and low pass filters in the feedback path.
• Drift function for controlling oscillator pitch instability.

Feldspar costs $16.95 which also includes FeldsparFX, a VST effect plug-in based on Feldspar's architecture. A demo version is available; it is fully functional except the output periodically drops to silence.