User Manual
This manual will explain the basic functions and usage of the K4815 Pattern
Generator for VCV Rack. If you have any questions please ask on the VCV Rack
forum or contact us.
First Use
When you first start using the K4815 you can initialize the module to get
a reasonable set of default parameters to work with. The main things are to
use a short GATE TIME, INT clock mode, and CV/GATE mode. The module will have
reasonable settings when you first place it into your rack. Connect the CV
output to an oscillator pitch input, and the gate output to your envelope
generator. This gives the most basic type of use case for the K4815 generating
melodic and rhythmic patterns.
Pattern Generator Concept
The K4815 Pattern Generator can generate melodies, rhythms and other CV and gate
signals for a number of uses. The basic concept involes an 8x8 grid of LEDs and
a single playback ball that travels around the display according to the
currently selected motion type. When the ball lands on a space, if it's lit up
(by the selected pattern) a note or CV is output on the CV/gate jacks. The selected
note is chosen based on the tonality and range controls.
The pattern generator concept employed in the K4815 is one that can be thought
of as three separate layers of control:
- Scale - The scale is the very lowest layer. The notes mapped to each location on the 8x8 grid are set by the chosen scale. Where in most sequencers the notes are assigned by the user, the K4815 fixes the notes to the grid locations. You can choose either major or minor tonality, as well as large or small scale span. This may seem like a limitation, but it's not as you will soon see.
- Pattern Type - The pattern is set with the PATTERN TYPE control and is shown on the background of the LED grid at all times. It defines which notes on the grid will play as the playback ball moves around the display. If a note is lit, it will play. The pattern defines the overall sound of playback, and can also affect how sparse or dense the pattern is.
- Motion Type - The motion is set with the MOTION TYPE control. The motion type defines how the playback ball will move around the grid during playback. A motion contains up to 64 steps, each of which can move to any position on the 8x8 grid. If the ball lands on a grid location which is lit by the pattern, the underlying scale note will play, otherwise the previous note will keep playing. (depending on the GATE TIME setting) The combination of settings for the motion type and pattern type offers an incredible array of rhythmic and melodic sequences.
Controls and Jacks
GATE TIME
The GATE TIME control affects how long the gate will stay on when each note is played.
Start with a low setting and then increase to taste. Many positions on the knob will
produce a gate that is longer than one step. Depending on the pattern you choose the
gate may not turn off between notes. This is designed to allow both staccato as well
as legato playing.
CLOCK SPEED
The CLOCK SPEED control affects the speed of the internal clock generator, or the clock
divider setting of the external clock input. When using in INT mode, turning all the way
counter-clockwise will stop the clock completely.
When using with an external clock, the CLOCK SPEED control will affect how many clock
pulses must be received on the CLOCK IN jack to advance to the next step. Typical settings
are between 1 and 24 pulses. Please note that the GATE TIME control uses clock ticks and
not time to determine the length of the gate output. Please use an external clock with
more than 1 pulse per step if you want control over the gate length.
MOTION LENGTH
The MOTION LENGTH control adjusts how many steps from the motion will be played before
restarting. From 1-64 steps is possible. Not all motion types have a total of 64 steps.
Try using unusual lengths and multiple K4815s or other sequencers to create polyrhythms.
PATTERN TYPE
The PATTERN TYPE control selects which of 32 built-in patterns are used. Patterns are
essentially gate patterns. If the playback ball lands on a lit space a note will be
played, otherwise a rest will be played.
OUTPUT OFFSET
The OUTPUT OFFSET control adjusts the range of notes used when generating output voltages
on the CV jack. By default scales use either 2 or 4 octaves of range. The OUTPUT OFFSET
allows you to shift the notes up and down without retuning your oscillators.
MOTION TYPE
The MOTION TYPE control is the only rotary control on the K4815 which acts like an endless
encoder instead of a potentiometer. It is used to select one of 64 different built-in motion
types. The motions affect how the playback ball modes around on the display. A full list
of built-in motion types are shown below.
Motion types 1-48 are pre-programmed and can be changed using the K4815P Programmer module.
Motion types 49-64 are random and are generated in real-time based on filters which differ
for each type.
Clock - INT/EXT, CLOCK IN and RESET IN
The clock section drives the module and advances the playback ball, playing and stopping
notes. The internal clock allows the K4815 to run by itself. Alternately you can supply
your own clock to the CLOCK IN jack. The INT/EXT switch selects whether the internal or
external clock is used. The internally generated clock runs at 24PPQ (pulses per quarter)
and the ball moves every 1/16th note. (4 times per beat)
Direction - FWD/REV and DIR IN
The playback direction can be controlled using the FWD/REV switch or with an external
voltage. The DIR IN jack will flip whatever direction is currently set on the FWD/REV switch.
Tonality - MAJ/MIN and LARGE/SMALL
The MAJ/MIN switch selects which scale will be used. Scales are mapped left to right in
rows and always contain eight notes. Each row is the same as the previous one except for
octave transposing. The MAJ scale is a normal major scale. The MIN scale is a minor scale
with the 3rd and 7th degree lowered. (Dorian scale)
The LARGE/SMALL switch affects the number of octaves used by the scales. In small mode,
two octaves are used: every other row is an octave higher than the previous one. In large
mode four octaves are used. Each subsequent row is an octave higher than the previous one.
Outputs - CV/GATE, X/Y
The CV/GATE output jacks carry the output signals from the K4815. The CV/GATE / X/Y switch
selects one of two outputs modes:
- CV/GATE mode - The CV/X jack will output a pitch signal at 1V/octave.
The GATE/Y jack will output a gate signal for each note.
- X/Y mode - The CV/X jack will output the X position of the playback ball.
The GATE/Y jack will output the Y position of the playback ball. The outputs will only
change when a lit space is landed on by the playback ball.
Memory Slots
The VCV version of the K4815 can store multiple sets of patterns, motions and
scales to be used at any time. These memory slots are stored in the K4815 JSON
file in your Rack directory. All memory slots are global to VCV Rack and available
from any patch. If you edit any data from one patch, other patches using the same
memory slot will be able to see the changes.
Themes
The K4815 supports different themes. You can choose from the Classic
theme that resembles the hardware K4815, or the Dark theme that resembles
the new trend of black PCB panels with gold design details. Expander modules follow
the chosen theme of the K4815 so you only have to set it once.
Gate Time Mode
The K4815 hardware version determines its gate time solely from the internal or external
clocks. This allows smooth scaling of the tempo from any clock source. However when using
an external clock with a 1:1 clock to step ratio, it is not possible to generate clocks
shorter than 1 clock pulse. This means that in some setups the GATE output will never turn
off. To make the VCV Rack version more flexible a second mode has been added which operates
on a timer. In this mode the gate time will be independent of the clock speed.
To change the gate mode, right click on the K4815 module. The mode is stored in the patch.
- Classic Mode - Gate time is determined by the internal or external clock.
- Timer Mode - Gate time is controlled by a timer. The gate pulse length can be set from about 16ms to 1 second.
Factory Pattern Types
Factory Motion Types
- Sequential left to right and top to bottom.
- Sequential top to bottom and left to right.
- Sequential zig zag left/right from top to bottom.
- Sequential zig-zag up/down and from left to right.
- Jumping from the start.
- Crazier jumping from the start.
- Spiral
- Diagonal zig-zag from bottom left corner.
- Skipping zig-zag from bottom right corner.
- Up and down triads.
- Octave jumping 5ths.
- Octave jumping wiggly worm.
- Octave jumping rows of four.
- Wiggles in different directions.
- Preset scatter 1.
- Preset scatter 2.
- Preset scatter 3.
- Ping-pong horizontal mirror reflection.
- Cat.
- Hanon.
- Diagonal zig-zag from bottom right corner.
- Diagonal zig-zag ping-pong from bottom right corner.
- X circle
- Stars.
- Ropes and knots.
- Squares of different sizes.
- Hurricane shape.
- C-E-G Triad
- D-F-A Triad
- C-E-G-B Triad
- D-F-A-C Triad
- C-E-G-C Triads Up/Down
- E-C-C-G Triads
- F-D-A Triads
- The Sound of Five
- Slither
- Mini Slither
- Mini Slither 2
- Crossing Over
- Groove 1
- Groove 2
- Groove 3
- Groove 4
- Groove 5
- Groove 6
- Groove 7
- Groove 8
- Groove 9
- Random - Seconds
- Random - Thirds
- Random - Fifths
- Random - Row 1
- Random - Rows 1 and 2
- Random - 1, 2, 3 and 4
- Random - 1, 2, 5 and 6
- Random - All Notes
- Random - Seconds
- Random - Thirds
- Random - Fifths
- Random - Row 1
- Random - Rows 1 and 2
- Random - 1, 2, 3 and 4
- Random - 1, 2, 5 and 6
- Random - All Notes
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