MF-101S Lowpass Filter

Name: MF-101S Lowpass Filter
Price: 79 USD
Author: Moog

by Moog · Filter · Moog ladder filter with envelope follower

Not rated yet

MF-101S Lowpass Filter is Moog's software version of the MF-101 Moogerfooger pedal, a 4-pole ladder lowpass filter with an envelope follower.

It adds stereo operation and CV-style modulation inputs, and costs $79.

Best for: Keys & Synths, Guitars, Bass, Drums, Sound Design. Genres: Electronic & EDM, Rock & Indie, Hip-Hop & Trap.

Keywords: drums, bass, classic, heavy, synths, dark, electric guitar, thick, 90s, extreme, fat, built-in mix knob, mixing, sound design, subtle, thin, utility.

What it does

The MF-101S is Moog's own plugin version of the 1998 Moogerfooger MF-101 pedal, "a re-invention of the classic Moog MF-101 analog effects pedal." It pairs a 4-pole Moog ladder lowpass filter with an envelope follower, so the cutoff can sweep with the dynamics of what you play.

Ladder filter: a Moog ladder lowpass with Cutoff and Resonance, switchable between a 12dB/octave two-pole and the classic 24dB/octave four-pole mode, and able to self-oscillate.
Envelope follower: Envelope Amount lets the input level push the cutoff up or down (either polarity), for auto-wah and "quacky" envelope-filter sweeps; a Follow Rate knob sets how fast it responds, replacing the pedal's Smooth/Fast switch.
Mono or stereo envelope: the follower can track a summed mono signal or each channel separately, which the original pedal could not do.
Stereo Response: shapes the curve of the envelope follower's response across the stereo field.
Mix: a wet/dry control for blending the filtered signal with the original.
CV inputs: virtual CV inputs for Cutoff, Resonance, Envelope Amount and Mix, each with an attenuator, which can be driven from other Moogerfooger plugins in the same session.
Beyond the pedal: presets and multiple instances, and none of the hardware's self-noise.

KVR lists version 1.3.0. It is also part of Moog's bundle of seven Moogerfooger plugins.

Source: Moog product page

When to use it

MF-101S is the pick when you want the official Moog ladder sound with an envelope follower, in a simple pedal-style layout. Compared with Volcano 3 or FilterFreak, it offers only lowpass (in two- or four-pole form) and no multi-filter routing or complex modulation, but it is quicker to set up for envelope-driven sweeps. Filter M12 and Filter MS-20 from Arturia model other classic synth filters with more filter modes, while MF-101S is specifically the heavy Moog four-pole character. It is also darker than most of these, since its cutoff tops out at 12kHz, and its CV inputs let other Moogerfooger plugins in the session modulate it.

Best for: envelope-driven Moog filter sweeps and auto-wah on synths, bass, guitar and drums.
Genres: electronic, funk, rock and hip-hop.
Look elsewhere if: you need many filter types, deep modulation or a big self-oscillating low end; Volcano 3 or FilterFreak do more.
Tip: Sound On Sound found it ideal for auto-wah and for shaping transient-rich sources like drums; adjust Follow Rate to tighten the envelope response.

What producers say

Reviewers praised its heavy, thick Moog tone, with the low maximum cutoff and a thinner low end than the pedal as the main reservations.

Sound On Sound (Robin Bigwood, 2023, reviewing the Moogerfooger bundle) said the four-pole setting has "that inimitable heavy, thick Moog quality," but found the 12kHz top cutoff makes tracks darker "even when it's fully open."
MusicRadar (Robbie Stamp, 2022) praised the "squelchy, quacky" tones and the stereo envelope following, but noted some lost low-end fatness compared with the hardware and self-oscillation that cuts out at around 275Hz.
KVR user rated it 5 out of 5 (one review, 2024), saying it ranges "from subtle effects to wild, far-out sounds" while noting the premium price.
Criticisms: no MIDI Learn, tempo-synced LFO divisions not shown, and a window that can't be resized.

Where to buy

Tutorials and reviews

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