Metropolix: Eight Steps, But Far From the End

At first, Intellijel demonstratively sticks to the repetitive motif. Metropolix controls Atlantix via pitch and gate; the occasional deviation gets its own control path. The pulser on Tangrams generates pulses at unsynchronized intervals, triggering an envelope. This lands at the X input of Metropolix, which is assigned the Octave function.

While experimenting, the presenter first lengthens the envelope so the octave jump is pronounced enough. Then, the event is linked to a second envelope for the drive control of the Sealegs delay. The higher note thus receives its own effect accent. This is a nice design decision: Not everything is moving all the time; a specific deviation is given weight. Intellijel’s guiding principle for this:

For the actual fill, Intellijel uses the Y input with the Pitch Pre assignment. A mod lane is set to gate toggle, slowed down with a divider of eight, and a trigger is placed on the last step. Via the expander, this impulse goes to a Quadrax channel. Its envelope leads back to the Y input: Metropolix thus organizes the timing of its own external intervention.

It is precisely the subsequent correction that makes the demonstration interesting. The modulation already works, but lasts too long. Intellijel shortens the envelope until only a few notes are changed. Here, the programmed basic pattern remains unchanged, not every output pitch. This distinction is important: After all, the fill should be audible, but not immediately take the lead role.

Melvin from Optoproductions, in his video from March 4, 2024, works with Detroit, a Metropolix-like sequencer in VCV Rack. It’s not the same hardware nor the same patch. Still, his view on the eight steps is insightful: With a set length of eleven steps, the pattern runs through once completely and then three more steps before resetting.

Melvin also demonstrates the pulse count: Individual steps can linger longer instead of immediately making way for the next. Together with slide, this changes the articulation of the figure. More musical length here requires neither additional pitch knobs nor a second melody. Melvin sums up the repeat option succinctly:

In the finished Detroit patch, Melvin even derives the bass voice from existing material. He taps gate and pitch CV from the main sequence and adds a clock divider and sample & hold. The bass thus only occasionally takes on a pitch value. It remains related to the melody but does not follow its every move.

While Intellijel deliberately works towards a quick return for the fill, what Melvin likes about this bass derivation is precisely the unpredictability due to the unusual clock rate. These are different musical decisions: there, a measured exception within the motif; here, an accompanying voice with its own temporal behavior.