Bastl Instruments NEO TRINITY: Envelopes and Rhythmic Alchemy in Eurorack

The video opens with Václav introducing the NEO TRINITY as a modulation hub that rethinks how rhythm and envelope generation interact in Eurorack. Traditionally, rhythm in modular setups is built from triggers and gates, which are then routed to envelopes for shaping sound. Bastl’s NEO TRINITY, however, fuses these concepts, allowing users to generate rhythms and envelopes from a single interface.

This integration means you’re not just firing off envelopes with external triggers—you’re sculpting both the timing and the contour of your modulation in one go. The rate knob becomes central, letting you adjust envelope lengths on the fly, while the system’s architecture encourages experimentation with rhythmic complexity and envelope automation. It’s a design that invites patchers to think beyond the usual trigger-to-envelope workflow.

Automation in the NEO TRINITY is split between trigger recording and rate knob modulation, giving users hands-on control over rhythmic patterns. Recording triggers is as simple as holding the rec button and pressing shift, instantly looping your input. If you need to tidy up, selectively erasing or clearing entire sequences is just a button combo away.

Quantization can be toggled, allowing sequences to lock tightly to the clock or drift into more human, groovy territory. There’s also a trigger generator with multiple algorithms—Euclidean, Divider, and preset banks for kicks, snares, and hi-hats—plus a random mode for unpredictable results. The rate knob determines the density of triggers, making it easy to dial in anything from sparse pulses to frantic bursts.

Envelope shaping on the NEO TRINITY is both flexible and immediate. Four main shapes are available: simple decay, variable shape (with attack and decay), attack-only, and a pulse mode. Each can be selected via shift and the channel buttons, with the rate knob adjusting decay, attack, or pulse width depending on the mode. The variable shape stands out, offering everything from short pulses to reversed envelopes, and all shapes can be automated for evolving modulation.

Re-triggering can be enabled or disabled, affecting whether envelopes complete their cycle before restarting—ideal for creating rhythm variations by simply lengthening or shortening the envelope. The slew mode (attack-hold-release) responds to gate durations, holding the envelope as long as the gate is high, which is perfect for durational tones or slides. This mode also doubles as a slew limiter, letting you process external voltages and introduce glide or lag into your modulation paths.

Input modes further expand the envelope’s behaviour. Feeding external CV into the envelope channel and adjusting the input mode allows for envelope inversion, logarithmic or exponential shaping, and even using the envelope as a trigger-to-gate converter. The video demonstrates how patching the envelope output back into its input can morph the contour from exponential to logarithmic, while attenuated and inverted modes offer even more nuanced control for percussive or evolving sounds.

The NEO TRINITY’s versatility shines in the patch examples, where polyrhythms and external CV sources are brought into play. Václav demonstrates how to set different sequence lengths on separate channels, creating interlocking patterns and shifting downbeats. Sequences can be rotated, muted, and layered, making it easy to build complex, performative rhythms on the fly.

External CV inputs are used to modulate envelope behaviour, with meta inputs allowing for randomisation and probability effects. By patching random voltages into the meta input and adjusting its mode, the rate knob can be influenced for evolving gate lengths and skipped triggers. This opens up a world of generative possibilities, from subtle groove variations to wild, unpredictable modulation.