Steve’s MS-22 Eurorack Filter

The MS-22 is a dual voltage controlled filter, inspired by the classic Korg MS-20 filter, with an innovative modulation matrix and one of the highest function-to-hp ratios in the land of Eurorack. This module was inspired by many pleasant chats with tech journalist Steve O’Hear. 

What makes the MS-22 unique

The MS-22 contains two dedicated filter circuits, one low-pass and the other a high-pass. These are configured in series, the low-pass going into the high-pass. This configuration allows for a unique duophonic fighting resonance behaviour (see the demo video below). The cutoff frequencies of both filters can be CV’ed. Compared to most bread-and-butter MS-20 clones, the MS-22 is twice the amount of filter condensed down into half the package (4HP).

Furthermore, the MS-22 also possesses the following selling points :

• The MS-22 offers CV control over input gain, basically, this allows you to either CV the level of filter overdrive or use it as A VCA for the signal going into the filter
• The MS-22 offers CV control over resonance, the MS-22’s resonance can also be pushed way further compared to Korg’s MS-20
• The MS-22 has a link switch, which links the cutoff frequencies of the low-pass and high-pass filters in two different ratios. This creates two flavors of band-pass filters, of which the bandwidth can be tweaked and CV’ed. The switch itself also serves as an awesome performance effect as you can use it to create an instant drop. I demonstrate this near the end of this video.
• The MS-22 has a unique modulation matrix that allows configuring many internal patches without using cables. The modulation matrix is designed to encourage happy accidents!

The next batch of Steve’s MS-22 is planned to ship in April 2021. Pre-orders for this batch starting next week (barring zombie apocalypse happening). 

Freak Firmware v2.5

You may already know because most of the new features were requested by the Vult DSP customers. Vult DSP implemented almost all the requests; in one shape or other. The ones that didn’t implemented, are safely stored in the Vult DSP backlog and will work on them for a future release.

This release has a lot of UI improvements. Probably the most important is that now you can select filters backward! If you keep the filter button pressed for about 1 second it will go to the previous model.

A silent improvement that you may not notice is that now the filters change without producing audible clicks or pops. This was a bit tricky to get right.

More settings

In the previous release, Vult DSP introduced the possibility of using “integrated VCAs” to control the filter output. In this release there are a few extra things that you can configure in your module:

• Output signal range: lower the volume of the sound
• Modulations voltage range: accept either 5 or 10 V
• Stereo modulation: cutoff input inversely modulates the the filters
• Output mix: mix the L and R channels

New models

The first new model is Phonok: vowel resonator. Phonok consists of a pair of LP and BP filters tuned to the two main formant frequencies. This resonator changes the tone of the input signal and makes it sound like the corresponding vowel. Phonok can be use to add some nice harmonics to the sound or to make your filter scream in pain “ai-ai-ai”.

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Nurage gets some love in this release. Vult DSP has been obsessively experimenting with vactrols in order to improve my models. My new vactrol model is nicer more nonlinear. Since simulated vactrols can be modified at will, the Nurage filter includes now three types. Basically, each model changes in a way that makes it feel like it has a longer “decay”.

The last addition is Nurage-VCA. Low Pass Gates usually have a mode that, for lack of a better name, it is called “both”: a low pass filter and a VCA. Because this mode changes the gain, it also affects the resonance. In this case I have replaced the resonance control for a single parameter that morphs between the different vactrol models. The result is a kind of “decay” control, but with a nice and natural envelope.

Current Filters included:

• Tangents: Steiner-Parker filter (three variations, LP, HP, BP).
• Lateralus: Ladder filter (6, 12, 8 and 24dB options)
• Nurage: Low pass gate/Borg filter 
• Nurage-VCA: VCA+LPG variable vactrol
• Ferox: CMOS filter (LP, HP, BP, Notch)
• Vortex: Russian filter (LP, BP)
• Stabile: State-Variable filter (LP, HP, BP)
• Unstabile Circuit bent State-Variable filter (LP, HP, BP)
• Vorg: MS-20 style filter (LP, HP)
• Rescomb: Resonant Comb filter (Comb+ and Comb-)
• Boomstick: Sallen-Key filter (LP,HP)
• Disjoint: DJ-Style filter (48db, 96dB)
• Debriatus: Wave Destructor (Bit Crush, Wave Fold, Distortion)
• Nopskate: Flip-flop octaver
• Flame: Analog distortion (Rodent, Cylinder)
• Phonok: Vowel resonator

Stability

This new firmware also has a lot of small optimizations that should make the module more stable. If you ever experienced your module freezing, I apologize for that. Hopefully, all future releases will be rock-solid now that I have detected the root of the issue.

Pricing and Availability

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You can get the new firmware following the links in the main Freak page. The filter is available fully assembled or as DIY kit.

IKARIE Stereo/Dual Peak Eurorack Filter Module

Ikarie is a uniquely sculpted, flexible stereo or dual peak filter module. It can continuously transition between lowpass and highpass filtering with a single knob. It also packs in an envelope follower for the incoming audio signal, which comes in handy when you’re looking to increase your sound’s internal animation.

IKARIE Features

• two parallel filter cores (left and right)
• based on 12dB/oct state variable filter topology
• unique lowpass/highpass switching control scheme
• well balanced voltage controlled resonance circuit
• envelope follower with 3 decay settings
• input gain up to 5 times
• stereo modulation – either panning of filter detuning
• flexible patch programmable topology
• beyond output for difference spectrums (twin peak filter)
• modulation attenuverter
• v/oct input with scaling trimmer accessible from the front panel
• output stereo VCA

Two parallel filter cores can be modulated in sync for work in the stereo realm, set apart for unique stereo effects (with either mono or stereo signal at the base), or chained together to make a 24 dB filter.

With only the mono output of the filter used, Ikarie behaves as a dual peak filter, which evokes formant-type sounds and rich, at will piercing, throaty resonance. The Beyond output gives you the spectral difference of the two filters, effectively turning the unit into a so-called twin peak filter.

Add an internal VCA, CV control over panning and resonance, optional overdrive of the input, and you can explore a vast universe of sound design possibilities, from liquidy through pinged percussive to lush and eerie. All in a very compact form factor, with tons of space for precision and creativity.

This module results from a collaboration between Václav Peloušek of Bastl Instruments and Peter Edwards of Casperelectronics. While Edwards’ obsessive attention to detail gave this filter a uniquely balanced resonance and envelope response, the expertise of Peloušek delivered a one-hand user experience filter with a distinctive control scheme at a minimal footprint.

About Bastl

Bastl Instruments (est. 2013) is an indie company focusing on the development and production of a variety of electronic musical instruments: portable sound boxes, standalone analog synthesizers, granular samplers, studio instruments, and utilities, Eurorack modules, and fully-featured Eurorack modular synthesizer systems. Bastl is based in Brno, Czech Republic, but our products have gained a worldwide fanbase. The Bastl Instruments gear has received raving reviews, and it has been used by electronic music legends such as Depeche Mode, Nine Inch Nails, or Radiohead. Bastl organizes all sorts of projects for both local and global communities, such as parties, concerts, DIY workshops, courses, coffee roasting, record label, and even clothing production.

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