Sketch Audio has released Series 9000, a low-pass filter and distortion plug-in based on the sixth-order filter design found in a rackmount sampler from the late 1980s. The new release recreates the original 36 dB per octave rolloff characteristic while introducing additional controls designed for contemporary production workflows.
At the core of Series 9000 is a steep low-pass filter with a 36 dB per octave slope. According to Sketch Audio, the filter mirrors the behaviour of the original hardware unit, including the detail that it does not fully close at minimum cutoff, allowing part of the source signal to remain audible. This design maintains the underlying character of the sound even at lower cutoff settings.
The plug-in combines this filter architecture with integrated distortion and modulation features, presented through four primary controls:
- Cutoff – Adjusts the filter cutoff frequency.
- Drive – Introduces custom saturation stages embedded within each filter stage, remaining fully clean at 0 dB.
- Q – Controls filter resonance.
- Env – Applies envelope follower modulation to the cutoff frequency, with an adaptive release characteristic.
The inclusion of per-stage saturation allows users to introduce harmonic content directly within the filtering process. The envelope follower enables dynamic modulation of the cutoff based on incoming signal amplitude, supporting expressive filtering effects that respond to performance or program material.
Series 9000 is available in AAX, AUv2, AUv3, CLAP, and VST3 formats. It supports macOS, Windows, and iOS platforms. Desktop installers require a free Sketch Audio account, while the iOS version is distributed via the App Store.
The release is part of Sketch Audio’s ongoing Nugget Basket series, a collection of free plug-ins with new additions introduced on a monthly basis. For users seeking expanded functionality, Sketch Audio also offers Scissor Hands, which builds on the Series 9000 concept by adding a high-pass filter, additional filter orders, and extended modulation options.
Series 9000 is free to download from Sketch Audio’s website. Desktop versions require a free Sketch Audio account. The iOS version is available via the App Store.
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