AI Synthesis - AI250 BXR

Vintage nuclear test equipment is not the most obvious starting point for a Eurorack module, which already makes the AI250 BXR rather unusual. Boxcar averagers were laboratory instruments used to extract useful information from fast, repeating signals buried in noise, and Abraham Ingle of AI Synthesis has taken the real-time mathematical section of these systems and given it a musical purpose. His main reference was the Stanford Research Systems SR-235 Analog Processor. And while we're clearing up names, the AI in AI Synthesis solely stands for Abraham Ingle, so there's no artificial intelligence involved here…!

In practice, the BXR takes two signals, combines them mathematically and then passes the result through a second set of functions. Addition, subtraction, multiplication and division are among the options, with further processing covering things like squaring, square roots, logarithmic functions and differentiation. Ordinary waveforms come out harmonically coloured, rectified, spiky or pleasantly unhinged. Input B can also be handed over to the built-in 1V/oct oscillator, which offers 11 voltage-selectable wave shapes and both audio and LFO ranges. The module can therefore act as an audio mangler, a CV processor or a complete sound source in its own right.

There are two controls which sit at the centre of this process. Argument determines the relationship between A and B, Function decides what happens next, and both can be CV-controlled. The formulas printed around the knobs may look like something rescued from a physicist's notebook, but don't fret — sweep them, sequence them and listen. Oscillator shape, distortion and dry/wet mix are also under CV control, while two aptly named Geiger Gates derive stochastic gates from activity inside the processor. The guts of the BXR are digital in nature, built around 24-bit processing on the Daisy platform, but it's void of any display and menu diving. It behaves much more like a peculiar piece of old analog laboratory equipment: patch something in, turn a control and see what survives the experiment.

That specificity is probably what makes BXR so appealing. It is not simply another multifunction digital processor wearing a retro panel; the whole module grows out of one obscure piece of measurement technology and explores what happens when you treat its maths as a musical process. Judging by the demos, the answer can be surprisingly rich and rounded as well as crunchy, unstable and broken. A very intriguing and strange module — and considerably more musical than its nuclear-test ancestry might suggest.

Features:

• Digital audio/CV processor inspired by vintage boxcar averager systems, particularly the Stanford Research Systems SR-235 Analog Processor
• Works as audio mangler, CV processor/generator and VCO
• Two audio/CV inputs with individual level controls
• Input B can be replaced by the internal oscillator
• Input B level doubles as oscillator pitch control when the internal oscillator is active
• Argument section combines A and B using addition, subtraction, multiplication, division and other mathematical relationships
• Function section applies operations including square, square root, logarithmic and differential processing
• CV control over Argument and Function
• Built-in 1V/oct oscillator
• 11 voltage-selectable oscillator wave shapes
• Audio-rate and LFO oscillator ranges
• CV control over oscillator wave shape
• Built-in distortion
• Voltage-controlled dry/wet mix
• Two stochastic Geiger Gate outputs
• Main processed output
• Dedicated oscillator output
• Direct panel operation with seven knobs, three toggle switches and 12 jacks
• No display or menus
• 24-bit processing on the Electrosmith Daisy platform
• Firmware updatable
• Available with silver aluminium or black panel