Antkai has released a free virtual matrix synthesizer for Windows, Efta.High.

Features:

• Subtractive Synthesis.
• Voice: 8 (poly, legato, mono)
• OSC: 2 (4 wave types with mods)
• Filter: 2 (and 2 pitch mods)
• LFO: 4 (with mods, tempo sync and key sync)
• Matrix with “inverse” pins.
• + 64 presets.

You can preview the sound of Efta.High below: