BlaknBlu - Foxtrot Duo

BlaknBlu's Foxtrot Duo — Multi-Mode Filter Processor Packed with Three Different Models.

Following its larger predecessor — Foxtrot, the Duo comes equiped with three classic filter designs. Through detailed virtual analog modeling, it captures Moog's ladder, Korg's Sallen-and-Key, and Oberheim's SEM filters - each analyzed from the original circuits down to their smallest quirks.

The differences between them are quite clear: the ladder filter delivers warm, squelchy resonance, the Sallen-and-Key circuit moves from clean to screaming, while the SEM provides that characteristically smooth response. The digital architecture allows these filters to morph between low-pass, band-pass, and high-pass modes, while still staying very precise and controlled — something much harder to do with traditional analog circuits!

Run Foxtrot Duo as two independent filters, or switch to mono where both inputs sum to a pair of outputs with voltage-controlled stereo movement. The auxiliary CV input handles filter morphing, resonance, or stereo positioning depending on your needs.

Like their hardware ancestors, these virtual circuits respond beautifully when pushed. The Boost switch drives them into satisfying saturation - especially evident in the Sallen-and-Key filter's aggressive resonant peaks. A soft clipper with LED indicator keeps the wildest moments under control.

Features:

• Three filter models: Moog-style ladder, Korg MS-20 inspired, Oberheim SEM
• Morphing between LP, BP, and HP modes
• Mono and stereo operation
• Two CV inputs for cutoff (1V/oct tracking on one)
• Aux CV for filter morphing, resonance, or stereo movement
• Boost switch for saturation
• Soft clipper with LED indicator
• Dual attenuated inputs