GATESEQ

"Euclidean patterns" are generated from a fundamentally musical idea: given some number of possible positions in a sequence, distribute some number of events (say, 3 strikes of a drum) evenly across those positions. For a practical take on their derivation and theory, check out this artice from North Coast Synthesis. They are a common feature in eurorack rhythm generators, and for good reason: such patterns can be found in music across cultures. Once you start adding noise CV for probabilistic sequencing, combining patterns, and creatively patching to produce stepped modulation, you open up a vast space of generative rhythms. GATESEQ allows you to quickly implement these types of patching strategies, working in tandem with your other sequencers and sources to broaden your rhythmic palette.

Two euclidean sequencers (I and II) run in parallel. The sequences themselves are independent, creating two output channels from one step input. Sequencer I has an added layer of complexity: it can multiply and divide the input clock and offers an extra modulation parameter.

A logical operation between the sequences derives a third sequence. The output is distinct from main sequencer outputs but retains some of their "well balanced" nature. Some logical operations serve as reinforcement of the two main sequences, others provide more of a counterpoint.

In addition, sequence I controls the A channel of the main Via circuit and sequence II controls the B channel. Sequence events can be mapped to the sample and hold, and can gate the channel on and off as well, which resembles the behavior of a logical "and" (although these inputs can handle logic signals or continuous signals). This enables the module to "process" CV or gate sequences, serve as a simple audio gate, or even combine these process to create a complex 4th output.

If you haven't yet, take a glance at this introduction of Via's controls, IO, and user interface.

PTN I and the left knob are dedicated to controlling sequencer I. PTN I selects the playback pattern, and controls the sequence modulation operation given by the currently selected pattern set. For more on the control, check out the section on sequencer I.

PTN II selects the playback pattern for sequencer II.

For both of the PTN controls, a clockwise turn of the knob increases the density of gate on events in the sequence.

Each manual control is paired with a CV.

PTN I selects the pattern for sequencer I.

controls the sequencer I modulation operation. The right CV control is an attenuator for the modulation source at this input.

PTN II selects sequencer II's pattern. The right knob in the sequencer II section is an attenuator for the modulation source at this input.

STEP is the step input for the sequences. Think of it as the "master tempo" of the system. Sequencer II advances on a rising edge at the step input. Sequencer I can mimic this behavior, or it be driven with an internally generated clock timed by the step input depending on the mode of the I parameter.

RESET resets both the sequences to the first position. This can be used to impose repetition on the pattern outputs. The sequence lengths for I and II can be different, causing the outputs to phase against each other and repeat at odd numbers of steps. A sequence of length 5 against a sequence of length 7 will phase against each other and only repeat every 35 steps. A trigger at the reset input every 16 steps, for example, would bring this pattern in line with a more traditional 16-step sequence.

I is a direct output for sequencer I.

II is a direct output for sequencer II.

combines the two sequences according to the mode for the parameter.

A+B sums the A and B inputs according to the & and S+H parameters for each input.

When not showing menu information, the LEDs display information about the state of the module. The two LEDs connected to the analog inputs are illuminated whenever the sample and hold on that channel is holding a value. The LED connected to the sequencer I output is illuminated when the logic level is high, and similarly the LED connected to the sequencer II output shows the state of that sequencer.

The RGB display shows the state of the analog & gates and the logic output. The green LED is illuminated when the output is high. The red LED is illuminated when the gate on the A input is open. The blue LED is illuminated when the gate on the B input is open.

The red/green LED above it shows the state of the analog output. It is off at 0V and becomes brighter green with increasing positive voltages, and brighter red with increasing negative voltages.

The button graphics depict the flow of signals from the A and B inputs through the module. The top row corresponds to sequencer I / A input, the bottom to sequencer II / B input.

These select the set of euclidean patterns for each sequencer channel. There are 4 choices for each sequencer.

Each set for sequencer I specifies a clock multiplication option. (1) is 1/1, (2) is 3/2, (3) is 2/1, and (4) has a variable multiplier. controls the modulation parameter for a given sequencer mode. In modes 1 and 2, the modulation parameter is offset in steps of sequencer I against sequencer II. In mode 3, it is a shuffle/swing control, with shuffle on the left of the knob, straight-ahead timing at noon, and swing on the right. In mode 4, it controls the multiplier on the sequencer clock.

Holding the & button for sequencer II and tapping the & button for sequencer I toggles through one of 4 possible logical combinations of sequencers I and II and the output. The options are (1) and, (2) or, (3) xor, and (4) nor . The first three modes reinforce the main sequence patterns; the third provides a sort of "inverse pattern", a rhythmic counterpoint that fills the meter.

The clock driving sequencer I gates the logic signal, keeping the rising edges of the logic output aligned with the main sequencers.

The following tables show the patterns contained in each of the available sequencer banks. Turning the pattern selection control advances down through the rows. A green step represents a gate high event, and the number of boxes in each row represents the pattern lengths.