Sallen-Key Multimode Filter

Black Noise Modular Sallen-Key

Sallen-Key from Black Noise Modular is a multimode, MS-20-style filter with several unique features for adding expressive timbral movement to your sounds. It's comprised of two filters, a two pole low-pass, and a single pole high-pass, which can both be used together simultaneously. Just set the base frequency with the Cutoff knob, and crossfade between the two filters with the Fade knob. This unique feature opens up a lot of possibilities for adding unique, evolving textures to your sounds. Sallen-Key is especially useful when paired with oscillators, providing both a 1V/Oct input and FM input, enabling multi-layered filter movements for your synth voices that can morph along with pitch CV. The In Level knob allows you to set input gain of the signal running into the Sallen-Key, which can control the gain of particularly hot signals, or add some warmth to your signal pre-filter.

Like the filter that inspired it, the Sallen-Key's resonance provides a non-linear feedback path, which prevents the filter from clipping when self-oscillating. Because of this design, the resonance is highly dependent on the input gain, making the In Level knob that much more useful. While the Sallen-Key is certainly a faithful tribute to the MS-20 filter, Black Noise Modular takes this classic design even further by adding more creative tools for pushing your patches deeper into uncharted territory.

Sallen-Key Features

• Faithful MS-20-style filter
• LP/HP crossfade control
• Input gain control
• 1V/Oct and FM inputs