Moog MF-101S Lowpass Filter — Free Download

Purpose

The MF-101S Lowpass Filter brings the sound of the classic Moog MF-101 pedal into the digital domain. It offers a warm, musical lowpass filter that can shape any audio source—guitar, voice, synthesizer, or field recordings—with a smooth, organic character. The plug-in is designed to be expressive, responding to dynamics as naturally as the hardware original.

As a software instrument, it expands on the vintage design by adding stereo processing, extensive CV connectivity, and preset management. This makes it suitable for both traditional filtering tasks and creative sound design, allowing producers to add movement and texture to their tracks in ways that were previously only possible with modular hardware.

Key Capabilities

At its core, the MF-101S features a four-pole lowpass filter with adjustable cutoff, resonance, envelope amount, and mix. The envelope follower is a standout element: in mono mode it replicates the original single-channel behavior, while in stereo mode it creates two independent followers for the left and right channels, enabling nuanced spatial effects.

The STEREO RESPONSE parameter changes how the envelope curve reacts to the input’s dynamics, giving you control over the filter’s response feel. Additionally, the plug-in provides CV inputs for key parameters, allowing external modulators (such as LFOs or sequencers) to shape the sound, and each modulation can be attenuated to fine-tune the effect.

Workflow

In a typical session, you insert the MF-101S on an audio track or bus. Begin by setting the cutoff and resonance to taste, then adjust the envelope amount to make the filter follow the performance’s dynamics. Use the mix control to blend the filtered signal with the dry input for parallel processing.

For more complex setups, route CV sources from other plug-ins or hardware to the filter’s inputs to automate cutoff or resonance over time. Running multiple instances allows layering different filter settings across tracks. Presets help you save and recall your favorite configurations, speeding up your workflow during creative sessions.

Practical Applications

The MF-101S is versatile for many musical tasks. On a vocal track, it can create a classic telephone effect or add subtle movement via the envelope follower. For synthesizers and basslines, it thins out harsh frequencies or adds a resonant, synth-wave character. Guitarists can use it for pedal-style filtering with wobble and sweep.

In sound design, the stereo envelope followers allow the filter to pan different frequencies based on the source’s dynamics, producing evolving textures. With its CV inputs, it integrates into modular-style patching environments, generating complex rhythmic patterns or filter sweeps that respond to your control signal. This makes it a flexible tool for both subtle sweetening and bold experimental effects.

Key features

• Classic four-pole analog lowpass filter
• Mono or dual stereo envelope followers
• Stereo response control for envelope shaping
• CV inputs for cutoff, resonance, envelope amount, and mix
• Adjustable attenuation for CV modulations
• Supports multiple instances and presets

Best for

Best for producers and sound designers who want an authentic Moog filter with modern flexibility—ideal for adding warmth, movement, and dynamic filtering to vocals, synths, guitars, or any audio, particularly in stereo setups and modular-inspired workflows.