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CYCLE INSTRUMENTS TETRACHORDS Manual

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CYC LE I NST R UM E N TS
TETRACHORDS
M A NUA L
WO R K I N PR O G R E SS
5 DE C 20 23

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  • Page 1 CYC LE I NST R UM E N TS TETRACHORDS M A NUA L WO R K I N PR O G R E SS 5 DE C 20 23...

  • Page 2: Table Of Contents

    Triggering with CV Triggering with MIDI Tracks Triggering Outputs Input response Trig In response graph MIDI In response graph Shift Button Overview RGB Buttons Keyboard Mode Overview Path Overview Description Random Path Configuration TETRACHORDS | USER GUIDE PAGE | 2...
  • Page 3 Overview Detail Inversions Overview Cascading encoder inversions Inversion knob Reverse Button Overview Arp / Chord Button Overview Chromatic Button Overview Two active notes Three active notes Four active notes Step Sequencer Overview Description TETRACHORDS | USER GUIDE PAGE | 3...
  • Page 4 Edit all CV LFOs Overview Physical Connection Tetrachords Configuration Disting Ex Overview & Setup #14 Quad Envelope #19 Macro Oscillator #20 Resonator #21 Macro Oscillator 2 #23 Poly FM Just Friends Overview & Setup TETRACHORDS | USER GUIDE PAGE | 4...
  • Page 5 Select Mod Target Fine Tune Mod Response Invert Mod Response Disabling Mods Unmod Remove Cable Examples (i) Musical Mode (ii) Midi Out (iii) Rev 1 (iv) Vel Level (v) Next Pattern(Mod 6 Default) TETRACHORDS | USER GUIDE PAGE | 5...
  • Page 6 LED display settings Overview LED DISPLAY EDITOR Overview Editing White single colour LEDs Editing Generic Colour LEDs Editing TRACK Colour LEDs RGB editing quick quide Link Overview Details Appendices 1 - CONFIG.TXT Acknowledgements TETRACHORDS | USER GUIDE PAGE | 6...
  • Page 7 TETRACHORDS | USER GUIDE PAGE | 7...

  • Page 8: Index

    Controls Index TODO TETRACHORDS | USER GUIDE PAGE | 8...

  • Page 9: Reading This Guide

    The hope is that the overview sections will be sufficient for players who prefer to learn with minimal guidance whilst extra detail is available for those who want it. TETRACHORDS | USER GUIDE PAGE | 9...

  • Page 10: Before You Start

    It requires a standard Eurorack power supply, takes 36hp of rack space and requires instruments to connect to. The Tetrachords outputs MIDI notes and 4 channels of CV but on its own does not generate sounds. TETRACHORDS | USER GUIDE...

  • Page 11: Installation

    Installation TODO TETRACHORDS | USER GUIDE PAGE | 11...

  • Page 12: Initialise Patch

    Initialise patch Pressing and holding the SONG button and then pressing the RESET or SHIFT buttons initialises the Tetrachords. What initialising the Tetrachords means is detailed in the Musical Structures section of this guide. (cont.) TETRACHORDS | USER GUIDE PAGE | 12...

  • Page 13: First Patch

    Tetrachords TRIG IN jack. Connect a MIDI sequencer via either the MIDI IN jack or the USB C connector. The Tetrachords will respond to any F notes received on MIDI channel 5. Activate notes by pressing any of the 8 RGB NOTE BUTTONS.
  • Page 14 • The ARP/CHORD button has a dramatic effect when connected to MIDI OUT but doesn’t do anything interesting (in this patch) when the Tetrachords is connected to CV OUT only. • The SPREAD knob doesn’t do anything when the AMOUNT knob is at 12 o’clock.

  • Page 15: Tracks

    Tracks The Tetrachords features 4 polyphonic tracks with fixed CV inputs, assignable MIDI inputs and assignable CV and MIDI outputs. TRIG INS Assigned to tracks 1-4 CV OUTS respectively. Assigned by default to TRACK BUTTONS Select the active track. tracks 1-4 respectively MIDI INPUTS &...

  • Page 16: Triggering

    See the INTERNAL RHYTHM SEQUENCER section Tracks Triggering of this guide. Notes on the Tetrachords can be triggered by an external CV or MIDI connection. MIDI input connections are made Trig In connections 1 - 4 are used by USB or by the MIDI IN jack.

  • Page 17: Outputs

    Tracks Outputs The Tetrachords sends note information via its CV or MIDI outputs. By default, tracks 1 - 4 send one- volt per octave CV signals to CV OUTs 1 - 4 respectively. TODO - reference i2c MIDI output connections are made by USB or by the MIDI OUT jack.

  • Page 18: Input Response

    TODO does this belong here? Somehow indicate when a section is more informative than practical. When the Tetrachords receives a MIDI NOTE ON message or detects the rising edge of a CV GATE, up to three things happen. 1 or more MIDI NOTE ON messages are transmitted via any active MIDI OUTPUTS.

  • Page 19: Trig In Response Graph

    This symbol represents a Inputs are blue MIDI note on message This symbol represents a Outputs are black MIDI note off message. TRIG IN RESPONSE TRIG IN CV OUT PITCH CV OUT VELOCITY MIDI Time (cont.) TETRACHORDS | USER GUIDE PAGE | 19...

  • Page 20: Midi In Response Graph

    CV OUT PITCH CV OUT VELOCITY MIDI Time Note that the CV OUT pitch does not respond to a MIDI note off message or to the falling edge of a CV TRIG IN signal. TETRACHORDS | USER GUIDE PAGE | 20...

  • Page 21: Shift Button

    Shift Button Many of the Tetrachords controls have primary and secondary functions. Secondary functions are accessed using the SHIFT button. For example, pressing and holding the SHIFT button, then turning the PATH knob sets the amount of slew applied to the CV output.

  • Page 22: Rgb Buttons

    Pressing an RGB note button, results in a note being added to, or removed from, the current pattern. RGB note buttons are white when inactive. When active, they assume the colour associated with the current track. TETRACHORDS | USER GUIDE PAGE | 22...

  • Page 23: Keyboard Mode

    Keyboard Mode has been engaged. In Keyboard Mode, the RGB buttons can be triggered manually by pressing them. To exit Keyboard Mode, press the STEP SEQ button again (with or without the SHIFT button). TETRACHORDS | USER GUIDE PAGE | 23...

  • Page 24: Overview

    Pressing an RGB note button, results in a note being added to, or removed from, the current pattern. The order in which a pattern’s notes play is determined by the position of the PATH knob. TETRACHORDS | USER GUIDE PAGE | 24...

  • Page 25: Path

    There various path settings are described on the following pages. In the descriptions, note order refers to order in which the RGB note buttons are triggered. The buttons are referred to by number as illustrated below. (cont.) TETRACHORDS | USER GUIDE PAGE | 25...
  • Page 26 1 - 3 - 2 - 4 PATH 4 5 - 7 - 6 - 8 PATH 5 1 - 5 - 2 - 7 4 - 8 - 3 - 6 (cont.) TETRACHORDS | USER GUIDE PAGE | 26...
  • Page 27 5-note loop, consisting of some random combination of the currently active notes. In the default loop, active notes may be repeated or omitted. Press the random button once to re-randomise the pattern. (cont.) TETRACHORDS | USER GUIDE PAGE | 27...

  • Page 28: Random Path Configuration

    In this case, the length of the loop is equal to the number of active notes. TETRACHORDS | USER GUIDE PAGE | 28...

  • Page 29: Overview

    Sets the root note of the Sets the pattern for scale scale. notes 1 to 4 BUTTON Sets the interval TETRACHORD 2 KNOB between Tetrachord 1 & Sets the pattern for scale Tetrachord 2 notes 5 to 8 TETRACHORDS | USER GUIDE PAGE | 29...

  • Page 30: Display

    Notes active in the current scale are illuminated and notes outside the current scale are not. Here the LED ring displays a major scale, with notes 1, 2, 3, 4, 5, 6 & 7 active. TETRACHORDS | USER GUIDE PAGE | 30...

  • Page 31: Root Note

    B and second name minor. The technical term for a scale’s first name is root note. To adjust the root note on the Tetrachords, press and, whilst still pressing, turn the ROTARY ENCODER. There are 12 root note options, visually represented by the 12 LEDs surrounding the ROTARY ENCODER.

  • Page 32: Tetrachords

    A musical scale can be divided into two, four note halves, called tetrachords. This idea inspired the layout of the Tetrachords with the centre of the module being divided into two sections. The TETRACHORD 1 section, for controlling scale notes 1 - 4...

  • Page 33: Note Patterns

    Their second name is derived from the characteristic pattern of intervals, aka musical distances, between each note. Three of the panel controls on the Tetrachords module define the pattern of intervals for a scale. The first half of the scale is set by the TETRACHORD 1 KNOB.
  • Page 34 Observe that in some of the above examples, note 1 follows note 7. This is a feature of musical scales, after their final note, they begin again on their first note (though one octave higher). (cont.) TETRACHORDS | USER GUIDE PAGE | 34...
  • Page 35 Note: The Tetrachord 1 Lydian setting has no effect when 5 5 4 is set to 4. The Tetrachord 2 Lydian setting has no effect when 5 5 4 is set to 5. TETRACHORDS | USER GUIDE PAGE | 35...

  • Page 36: Rotary Encoder /Scale Rotation

    If the Rotary Encoder is turned one step clock-wise, note 2 of the LED ring turns red, indicating that RGB button 1 now corresponds to scale note 2. Again, subsequent RGB buttons correspond to subsequent scale notes. (cont.) TETRACHORDS | USER GUIDE PAGE | 36...
  • Page 37 As an example, the seven possible encoder settings for the natural minor scale are illustrated below. Theoretical note: these settings correspond to what are known as the 7 modes of the natural minor scale. (cont.) TETRACHORDS | USER GUIDE PAGE | 37...
  • Page 38 (cont.) TETRACHORDS | USER GUIDE PAGE | 38...
  • Page 39 Turning the encoder clock-wise after the 7th setting results in a return to the original setting, though with all notes shifted 1 octave higher. TETRACHORDS | USER GUIDE PAGE | 39...

  • Page 40: Scale Recipes

    Scales 6 - Scale recipes SCALE TETRACHORD 1 TETRACHORD 2 Major Natural Minor Harmonic Minor Half-Whole Diminished Blues (ish) Phrygian Dominant (cont.) TETRACHORDS | USER GUIDE PAGE | 40...
  • Page 41 SCALE TETRACHORD 1 TETRACHORD 2 Dorian Mode Phrygian mode Lydian Mode Myxolydian Mode Locrian Mode Whole Tone TETRACHORDS | USER GUIDE PAGE | 41...

  • Page 42: Overview

    Minor 3rd down Minor 3rd up Major 3rd up RGB BUTTONS 5-8 Modulate the tonal center up or down a third whilst changing the scale according to which of RGB buttons 1-4 is active. (cont.) TETRACHORDS | USER GUIDE PAGE | 42...
  • Page 43 3. Press an RGB button, listen to how things change, press an RGB button, listen to the change, press an RGB button, listen... For the curious, below is an example accompanied by a description of the mechanism behind PIVOT MODULATIONS. TETRACHORDS | USER GUIDE PAGE | 43...

  • Page 44: Overview

    Turning the rotary encoder, whilst the octave button is pressed, also changes the track octave setting. A clockwise turn increments the octave setting, an anti-clockwise setting decrements it. TETRACHORDS | USER GUIDE PAGE | 44...

  • Page 45: Overview

    The AMOUNT knob has no effect at the 12 o’clock position. When turned clockwise, the AMOUNT knob shifts selected notes up by 1 to 3 octaves. When turned counter-clockwise, the AMOUNT knob shifts selected notes down by 1 to 3 octaves. TETRACHORDS | USER GUIDE PAGE | 45...

  • Page 46: Detail

    Turning the AMOUNT knob counter- clockwise lowers notes by 1 to 3 octaves. In this setting, notes at the beginning of the SETTING 2 tetrachord will always be higher than those at the end. (cont.) TETRACHORDS | USER GUIDE PAGE | 46...
  • Page 47 In this setting, the amount knob affects SETTING 3 only the 1st and 3rd notes of the tetrachord. In this setting, the amount knob affects SETTING 4 only the 2nd and 4th notes of the tetrachord. (cont.) TETRACHORDS | USER GUIDE PAGE | 47...
  • Page 48 In this setting, the amount knob affects SETTING 5 only the middle notes of the tetrachord. In this section, the amount knob affects SETTING 6 only the outer notes of the tetrachord. TETRACHORDS | USER GUIDE PAGE | 48...

  • Page 49: Overview

    Similarly, pressing shift and turning the encoder counter-clockwise causes the highest active notes to be lowered one octave. Continuously turning the encoder counter- clockwise results in notes cascading downwards until they reach their lower limit TETRACHORDS | USER GUIDE PAGE | 49...

  • Page 50: Inversion Knob

    DROP 3 Notes 3 and 4 are lowered by 1 octave. DROP 2 Notes 5 and 6 are lowered by 1 octave. DROP 1 Notes 7 and 8 are lowered by 1 octave. (cont.) TETRACHORDS | USER GUIDE PAGE | 50...
  • Page 51 Notes 1 and 2 are raised by 1 octave. Notes 1, 2, 3 and 4 are raised by 1 octave. Notes 1, 2, 3, 4, 5 and 6 are raised by 1 octave. TETRACHORDS | USER GUIDE PAGE | 51...
  • Page 52 THEORETICAL DISCLAIMER (safe to ignore for everyone - possibly interesting to those familiar with inversions and associated terminology) The Tetrachords implementation of inversions does not align 100% with established practice. This is for pragmatic reasons, to make the INVERSION knob more useful and fun.

  • Page 53: Reverse Button

    Each tetrachord section features a reverse button, labelled REV. The reverse button reverses the order in which any active notes in the corresponding tetrachord are played. The LED above the button illuminates when reverse is engaged. TETRACHORDS | USER GUIDE PAGE | 53...

  • Page 54: Arp / Chord Button

    13 notes. The Tetrachords module can easily transmit 13 note chords via MIDI, however it is limited to a maximum of 4 simultaneous notes via CV.

  • Page 55: Overview

    The chromatic button affects a pattern differently depending on the how many notes are active in the corresponding tetrachord. The way this works is detailed on the following pages. TETRACHORDS | USER GUIDE PAGE | 55...

  • Page 56: Chromatic Button

    Scale notes 1 & 2 are now part of the current sequence. Press the chromatic button The 2 note i.e. the note between scale notes 1 & 2, is now part of the sequence also. (cont.) TETRACHORDS | USER GUIDE PAGE | 56...

  • Page 57: Three Active Notes

    Scale notes 1, 2 & 5 are now part of the current sequence. Press the chromatic button The 2 note i.e. the note between scale notes 1 & 2, is now part of the sequence also. (cont.) TETRACHORDS | USER GUIDE PAGE | 57...

  • Page 58: Four Active Notes

    The 2 note i.e. the note between scale notes 1 & 2, is now part of the sequence. The 4 note i.e. the note between scale notes 3 & 5, is now part of the sequence. TETRACHORDS | USER GUIDE PAGE | 58...

  • Page 59: Step Sequencer

    STEP SEQ button is held the point at which notes will be clears the current sequence added to or removed from the and starts a new one. sequence. TETRACHORDS | USER GUIDE PAGE | 59...

  • Page 60: Description

    32 notes. It works similarly to classic step-time sequencers such as found on the Roland SH-101. In regular Tetrachords operation, the order of notes is determined by the PATH knob, which selects one of the 6 pre-defined note patterns, or a randomised pattern.
  • Page 61 RGB button to clear the current sequence and start a new one. DELETE THE MOST RECENT NOTE Press and hold the STEP SEQ button then press the BACK button to clear a single note from the custom path. (cont.) TETRACHORDS | USER GUIDE PAGE | 61...
  • Page 62 STEP SEQUENCER LED RING DISPLAY When the STEP SEQ button is pressed, the RGB LED ring and the white LED PILLS display the seqeunce length (cont.) TETRACHORDS | USER GUIDE PAGE | 62...
  • Page 63 Connection The Tetrachords accepts MIDI input via 3.5mm stereo jack and USB C. The Tetrachords is configured as a class compliant USB C device. This means there is no need to install drivers but it will only pair with a USB host.

  • Page 64: Tracks

    Track 1 QUANTISE CV OUT 1 QUANTISATION To turn off quantisation, so the Tetrachords functions as a MIDI through and MIDI to CV/I2C box: Press and hold the SHIFT button then press and hold OCTAVE/MIDI IN. SHIFT can be released at this stage.

  • Page 65: Midi To Cv - Multiple Notes

    Assign CV OUTS 1 to 4 to TRACK 1 (page 92.) Connect a MIDI keyboard to the Tetrachords and set it to output on MIDI channel 1. Press and release a single note on the MIDI keyboard. All 4 CV OUTS will transmit a pitch corresponding to that single note.
  • Page 66 SIMPLE TRIGGER MODE (cont.) TETRACHORDS | USER GUIDE PAGE | 66...

  • Page 67: Channel Configuration

    Enabled channels are illuminated with the current track colour. Up to 16 channels can be set as input for each track. To access channels 9-16, press the RIGHT button. (cont.) TETRACHORDS | USER GUIDE PAGE | 67...
  • Page 68 8 channels. The brighter pill indicates the active page: 1st page 2nd page The LEFT and RIGHT buttons navigate between pages. (cont.) TETRACHORDS | USER GUIDE PAGE | 68...
  • Page 69 TETRACHORDS | USER GUIDE PAGE | 69...
  • Page 70 TRACKS 1, 2, 3 & 4 respectively. In-between notes trigger multiple TRACKS as illustrated above. Additionally, notes C# and D# cause TRACK 1, and any linked TRACKS, to progress to the previous or next PATTERN. (cont.) TETRACHORDS | USER GUIDE PAGE | 70...

  • Page 71: Channel Configuration

    The selected channel is illuminated with the current track colour. A single channel 1 - 16 can be selected. To select channels 9-16, turn the encoder clockwise, past the 8th setting. (cont.) TETRACHORDS | USER GUIDE PAGE | 71...
  • Page 72 Note that the RGB button display the LED RING display always agree i.e. they are always both on the same page. Channel 1 - 8 Channel 1 Channel 9 - 16 Channel 9 TETRACHORDS | USER GUIDE PAGE | 72...

  • Page 73: Midi Output

    1 to 4 respectively. MIDI is output via the 3.5mm stereo jack and USB C. The Tetrachords is configured as a class compliant USB C device. This means there is no need to install drivers however, it will only pair with a USB host.

  • Page 74: Channel Configuration

    Enabled channels are illuminated with the current track colour. Notes generated by the current track will output to every enabled MIDI channel. Up to 16 channels output channels can be set per track. (cont.) TETRACHORDS | USER GUIDE PAGE | 74...
  • Page 75 8 channels. The brighter pill indicates the active page: 1st page 2nd page The LEFT and RIGHT buttons navigate between pages. TETRACHORDS | USER GUIDE PAGE | 75...

  • Page 76: Midi Velocity Overview

    MIDI Velocity Overview When the SHIFT button is pressed and held, the five knobs below manipulate MIDI velocity values of sequenced notes. TETRACHORDS | USER GUIDE PAGE | 76...

  • Page 77: Arp Velocity

    Press SHIFT and turn the INVERSION / CHORD VEL knob. This sets the MIDI velocity for notes played when the ARP CHORD button is set to CHORD. CHORD VEL is set to 75 by default. (cont.) TETRACHORDS | USER GUIDE PAGE | 77...

  • Page 78: Random Velocity

    This adds a random component to the MIDI velocity of notes in the current pattern. The VEL RANDOM setting effects all notes, regardless of the ARP CHORD button setting. VEL RANDOM is set to 15% by default. (cont.) TETRACHORDS | USER GUIDE PAGE | 78...

  • Page 79: Midi Velocity Spread

    The VEL AMOUNT knob has no effect at the 12 o’clock position. When turned clockwise, the VEL AMOUNT knob increases the velocity of selected notes. When turned counter-clockwise, the VEL AMOUNT knob decreases the velocity of selected notes. TETRACHORDS | USER GUIDE PAGE | 79...
  • Page 80 (Buttons 1 - 4) (Buttons 5 - 8) In this setting, notes at the beginning of the SETTING 2 pattern will always be louder than those at the end. (cont.) TETRACHORDS | USER GUIDE PAGE | 80...
  • Page 81 In this setting, the amount knob affects SETTING 3 only the odd notes of the pattern. In this setting, the amount knob affects SETTING 4 only the even notes of the pattern. (cont.) TETRACHORDS | USER GUIDE PAGE | 81...
  • Page 82 In this setting, the amount knob affects SETTING 5 only the middle notes of the pattern. In this section, the amount knob affects SETTING 6 only the outer notes of the pattern. TETRACHORDS | USER GUIDE PAGE | 82...

  • Page 83: Midi Cc

    MIDI CC Pressing and holding SHIFT, then pressing the PROG/MIDI CC button puts the Tetrachords in MIDI CC MODE. Turning any of the 8 knobs generates MIDI CC messages. Each knob has a dedicated MIDI CC number and transmits values from 0-127.

  • Page 84: Example Patch

    1, MIDI CC 22. Initialise the Tetrachords (see page 12). Press SHIFT then press and hold PROG/MIDI CC to put the Tetrachords in MIDI CC MODE. SHIFT can be released at this point. Turn the PATH KNOB. As the PATH KNOB is turned, the Tetrachords streams MIDI CC messsages on MIDI CC 22.
  • Page 85 Turn the PATH KNOB fully counter- clockwise. The MIDI CC setting is stored in the current Tetrachords PATTERN, number 1. Release PROG/MIDI CC Hold PATTERN then press the RIGHT button to copy the current PATTERN to the next PATTERN slot.
  • Page 86 The 4th white LED pill goes dark indicating that MIDI CC on the 4th knob i.e. PATH, is inactive. Release PROG/MIDI CC MIDI CC messages will no longer be generated as patterns change. TETRACHORDS | USER GUIDE PAGE | 86...

  • Page 87: Encoder Overview

    CC MODE. Initialise the Tetrachords (see page 12). Press SHIFT then press and hold PROG/MIDI CC to put the Tetrachords in MIDI CC MODE. SHIFT can be released at this point. Press the ENCODER BUTTON. When the BUTTON is pressed, the Tetrachords transmits a value of 1 on MIDI CC 32.
  • Page 88 Turn the ENCODER As the ENCODER is turned, the Tetrachords streams MIDI CC messsages corresponding to the selected NOTE LEDS E.g. here the ENCODER will send a value sending a value of 8 over MIDI CC 32. Release PROG/MIDI CC...
  • Page 89 TETRACHORDS | USER GUIDE PAGE | 89...
  • Page 90 TETRACHORDS | USER GUIDE PAGE | 90...

  • Page 91: Cv Out

    Buttons 5 to 8 assign CV OUT 1 to 4, in gate mode, to the selected track. The assigned outputs send a gate signal, scaled according to the MIDI velocity value of the current note. TETRACHORDS | USER GUIDE PAGE | 91...

  • Page 92: Polyphonic Example

    When TRACK 1 is playing and the ARP CHORD button is set to CHORD, the 4 CV OUTS can transmit up to 4 different notes/ voltages. The way it works depends on how many notes are active. (cont.) TETRACHORDS | USER GUIDE PAGE | 92...
  • Page 93 When 3 notes are active, CV OUTS 1, 2 & 3 transmit the active notes/ voltages. CV OUT 4 duplicates note 1. RGB Button 1 note RGB Button 5 note RGB Button 7 note RGB Button 1 note (cont.) TETRACHORDS | USER GUIDE PAGE | 93...
  • Page 94 RGB Button 5 note E.g. when all notes are active, notes 5, 6, 7 & 8 are omitted. RGB Button 1 note RGB Button 2 note RGB Button 3 note RGB Button 4 note TETRACHORDS | USER GUIDE PAGE | 94...

  • Page 95: Gate Out Example

    For details of how to manipulate note velocity, refer to MIDI Velocity section of this guide. For details of how the gate output responds to the CV input, refer to the Trig Input Response section of this guide. TETRACHORDS | USER GUIDE PAGE | 95...

  • Page 96: Slew

    CV notes. When turned fully clockwise, the transition between CV notes is as slow as possible, approximately 5.5 seconds. Note that the transition time is independent of the distance between sequenced notes. TETRACHORDS | USER GUIDE PAGE | 96...

  • Page 97: Current Track Lfo

    Sets the LFO depth for all CV OUTS assigned to the current track. Note: the controls described above can be used to synchronize the LFOS of all CV outputs assigned to a track. TETRACHORDS | USER GUIDE PAGE | 97...

  • Page 98: Edit All Cv Lfos

    KNOBS 5 to 8 Set the LFO amount for CV OUTS 1 to 4 respectively. The controls described above can be used to independently set the LFOS of all CV outputs assigned to a track. TETRACHORDS | USER GUIDE PAGE | 98...

  • Page 99: Overview

    In a Eurorack system, i2c connections are typically made on the under side of modules. Currently, the Tetrachords is i2c compatible with the Expert Sleepers Disting EX, and the Mannequins Just Friends. More integrations are planned. Contact us with any requests or suggestions.

  • Page 100: Physical Connection

    SCL and SDA lines connectered to a power source via what are known as ‘pull-up resistors’. On the Tetrachords, pull-up resistors can be enabled or disabled via a switch located beside the 3-pin i2c connector. It is possible to daisy chain i2c connections. Some modules, such as the Just Friends have double connectors to facilitate this.

  • Page 101: Tetrachords Configuration

    Disting Ex Press the ENCODER BUTTON to activate/de-activate the connection for the selected track. When i2c is activated, the LED corresponding to the connected device will assume the colour of the selected TRACK. TETRACHORDS | USER GUIDE PAGE | 101...
  • Page 102 With the power to both modules off, physically connect the Tetrachords and Disting Ex i2c headers. The Tetrachords and Disting Ex both have i2c pull-up resistor enable switches. Ensure that one, and only one of these is enabled. With the Disting Ex powered on, enter the top level settings menu and then select MIDI/I2C page 1.
  • Page 103 This is because a handshake occurs between the Disting Ex and the Tetrachords when an i2c connection is activated. During this handshake, the Tetrachords learns what algorithm the Disting Ex is running and adjusts it’s settings accordingly. (cont.)

  • Page 104: #14 Quad Envelope

    #14 QUAD ENVELOPE Starter settings for a Quad Envelope with Envelopes 1 - 4 paired to Tetrachords CV outs 1 - 4. Each time a Tetrachords CV OUT is updated, the corresponding envelope is triggered. With this setup, Shape 1 is the shape for all 4 envelopes.

  • Page 105: #19 Macro Oscillator

    Starter settings for a single* voice routed to Disting Ex outputs 1 & 2. * Technically there are 4 voices but the Tetrachords’s chord feature isn’t currently compatible with the Resonator algorithm. Resonator → Parameter 26: Audio input → 0 0 None.

  • Page 106: Macro Oscillator

    Poly FM → Parameter 16 : Output 2 → 4 Outputs 1/2 Poly FM → Parameter 23 : Output 3 → 4 Outputs 1/2 Poly FM → Parameter 30 : Output 4 → 4 Outputs 1/2 TETRACHORDS | USER GUIDE PAGE | 106...

  • Page 107: Just Friends

    - Just Friends When Connected to the Tetrachords via i2c Just Friends operates in its Synthesis Mode, operating as a six voice polysynth with voices dynamically assigned. CONNECTION With the power to both modules off, physically connect the Tetrachords and Just Friends i2c headers.

  • Page 108: Tuning Mode

    RESET Abort calibration RGB BUTTONS LED RING Load/Select Tuner display/ LEFT (OR RIGHT) BUTTON calibration calibration progress Begin calibration setting. indicator Pressing SHIFT + LINK / places the Tetrachords in TUNING MODE. TETRACHORDS | USER GUIDE PAGE | 108...

  • Page 109: Tuning

    CV controlled oscillators in tune with MIDI instruments and with each other. To use the tuner, first connect any of the Tetrachords CV OUTS to an oscillator’s v/octave input. Then connect an oscillator output to TRIG IN 1.
  • Page 110 MIDI note 60. The LED ring indicates the tuning of the oscillator connected to TRIG IN 1. The LED ring tuning display mimics common instrument tuners. See details on the following page. (cont.) TETRACHORDS | USER GUIDE PAGE | 110...
  • Page 111 LED RING TUNER DISPLAY (less than 261.6Hz) Slightly low (slightly less than 261.6Hz) ‘In Tune’ 261.6Hz Slightly high (slightly greater than 261.6Hz) High (greater than 261.6Hz) (cont.) TETRACHORDS | USER GUIDE PAGE | 111...

  • Page 112: Troubleshooting Tuning

    Troubleshooting tuning The Tetrachords tuner works best with simple waveforms. Where possible use a square wave. Otherwise basic waveforms such as saw, triangle and sine waves can work well. The tuner may not work with more complex waveforms, though by all means try.

  • Page 113: Calibration

    Calibration The Tetrachords is capable of calibrating its CV OUTS to individual oscillators. This can significantly improve how in-tune oscillators will play when sequenced by the Tetrachords, especially for sequences with a wide pitch range. The calibration process currently takes between 1 to 2 minutes.

  • Page 114: Loading Calibrations

    Here LED pills 1 - 5 are illuminated, indicating that calibrations have been saved in slots 1 - 5. Pressing buttons 1 - 5 will load the corresponding saved calibration setting. (cont.) TETRACHORDS | USER GUIDE PAGE | 114...

  • Page 115: Saving Calibrations

    CV OUT you wish to use for the calibration e.g. press TRACK 1 if calibrating CV OUT 1 Connect the selected CV OUT to an oscillator’s v/octave input. Connect the oscillator’s output to TRIG IN 1. (cont.) TETRACHORDS | USER GUIDE PAGE | 115...
  • Page 116 Press one of RGB buttons 1 - 8 to select where the calibration is to be saved. The LED pill above the button will flash, indicating the slot where the calibration is to be saved. (cont.) TETRACHORDS | USER GUIDE PAGE | 116...
  • Page 117 No changes to calibration files or settings will be made if calibration is aborted. When calibration is complete, the Tetrachords exits TUNING MODE and can be operated as normal. TETRACHORDS | USER GUIDE PAGE | 117...

  • Page 118: Quick Start

    PATTERN to the previous PATTERN slot. Use the LEFT and RIGHT buttons to navigate between active patterns. Sending a trigger to MOD 6 advances to the next active PATTERN. This is equivalent to pressing the RIGHT button. TETRACHORDS | USER GUIDE PAGE | 118...

  • Page 119: Musical Structures

    Musical Structures Concept A SONG is the highest-level Tetrachords structure. A SONG consists of 8 PROGRESSIONS, labelled PROG on the faceplate. Each PROGRESSION can contain up to 8 PATTERNS TETRACHORDS | USER GUIDE PAGE | 119...

  • Page 120: Songs

    NOTE - to see which SONG slot is currently selected, press and hold SONG/SAVE. The white LED pills will indicate the current SONG slot. INITIALISING A SONG Hold SONG then press the RESET to clear/initialise the current SONG and all PROGRESSIONS within it. TETRACHORDS | USER GUIDE PAGE | 120...

  • Page 121: Progressions

    Hold PROGRESSION then press the RIGHT button to copy the current PROGRESSION to the next PROGRESSION slot. Hold PROGRESSION then press the LEFT button to copy the current PROGRESSION to the previous PROGRESSION slot. (cont.) TETRACHORDS | USER GUIDE PAGE | 121...
  • Page 122 INITIALISING PROGRESSIONS Hold PROGRESSION then press the RESET to initialise the current PROGRESSION and all PATTERNS within it. TETRACHORDS | USER GUIDE PAGE | 122...
  • Page 123 PATTERN to the next PATTERN slot. The LEFT and RIGHT buttons to navigate between active patterns. Sending a trigger to MOD 6 switches to the next active PATTERN. This is equivalent to pressing the RIGHT button. TETRACHORDS | USER GUIDE PAGE | 123...

  • Page 124: Display

    A dark pill indicates an inactive PATTERN. By default, PATTERN 1 playing and is the only active PATTERN. In the example below, PATTERN 1 is playing and PATTERNS 2 & 4 are active. TETRACHORDS | USER GUIDE PAGE | 124...

  • Page 125: Copying

    RIGHT button copies PATTERN 1 to PATTERN 2. Note that PATTERN 2 is now playing. Press and hold the PATTERN button and then press the LEFT ARROW button to copy the playing PATTERN to the previous PATTERN. TETRACHORDS | USER GUIDE PAGE | 125...

  • Page 126: Arrow Button Switching

    ... the first active PATTERN becomes the playing PATTERN. Conversely, if the first active PATTERN is the control PATTERN and the LEFT ARROW button is pressed..the last active PATTERN becomes the playing PATTERN. (cont.) TETRACHORDS | USER GUIDE PAGE | 126...

  • Page 127: Cv Switching

    PATTERN SWITCHING METHOD 2 - CV By default, sending a trigger to MOD 6 makes the next active PATTERN the control PATTERN. This is equivalent to pressing the RIGHT ARROW button. TETRACHORDS | USER GUIDE PAGE | 127...
  • Page 128 Scale settings Octave settings Spread settings Inversion settings Arp/Chord settings Chromatic settings Reverse settings Active note settings i.e. which notes play Custom pattern settings MIDI CC settings MIDI velocity settings LFO settings (cont.) TETRACHORDS | USER GUIDE PAGE | 128...

  • Page 129: Overview

    CV Modulation Overview Almost any of the Tetrachords’ settings may be precisely controlled via CV. Below is a quick example. The pages that follow explain the process in full and provide further examples. Plug a CV source into MOD 1.

  • Page 130: Cv Modulation

    CV Modulation The 6 MOD inputs can be used to control any (almost) of the Tetrachords’ settings via CV. Each input can be assigned to modulate multiple settings. Set up works as follows: Press and hold the MOD button. NOTE...

  • Page 131: Select Mod Input

    LEDs flash to indicate any parameter assigned to the newly selected MOD. The LED RING displays the value of any CV signal received by the selected mod. Positive CV Negative CV Max CV +5V (cont.) TETRACHORDS | USER GUIDE PAGE | 131...

  • Page 132: Select Mod Response

    In trigger mode, an incoming trigger causes the targeted control to cycle through its possible settings. By default, MOD 1 - MOD 5 are set to bi-polar response and MOD 6 is set to trigger. (cont.) TETRACHORDS | USER GUIDE PAGE | 132...

  • Page 133: Select Mod Target

    Use MOD 5 & MOD 6 for Triggers All mods can respond to trigger inputs, however, MOD 5 & MOD 6 have been designed to be more responsive and so are the best choice for time-sensitive trigger modulations. (cont.) TETRACHORDS | USER GUIDE PAGE | 133...

  • Page 134: Fine Tune Mod Response

    As do all 6 LEDs surrounding the TETRACHORD 1 KNOB. In this way the display indicates that the incoming CV may set the TETRACHORD 1 control to any of its 6 possible values. (cont.) TETRACHORDS | USER GUIDE PAGE | 134...
  • Page 135 At this point, de-selecting all of the RGB buttons TODO - reference UNMOD and link to disables modulation of the selected control. the diabling MODS section The RESET button works as a short cut for this. (cont.) TETRACHORDS | USER GUIDE PAGE | 135...

  • Page 136: Invert Mod Response

    When the MOD button is held, the LINK and JAM/READ/WRITE LEDs strobe in parallel to indicate this. With the MOD button held, pressing LINK or JAM/READ/WRITE, inverts the LED display and mod response.. BIPOLAR UNIPOLAR LYDIAN HARMONIC PHRYGIAN LYDIAN TRIGGER TETRACHORDS | USER GUIDE PAGE | 136...

  • Page 137: Disabling Mods

    Removing the cable temporarily disables any modulations associated with that MOD input. The MOD settings aren’t deleted when the cable is removed. Modulation resumes if the TODO - finish this cable is plugged back in. TETRACHORDS | USER GUIDE PAGE | 137...

  • Page 138: (I) Musical Mode

    Press RGB BUTTON 3 to select MOD 3 as the physical input Use RGB BUTTON 8 to select unipolar (0 to 5v) input. UNIPOLAR (0v to 5v) The AMOUNT 2 LED pulses right to indicate the unipolar setting. (cont.) TETRACHORDS | USER GUIDE PAGE | 138...
  • Page 139 MODE value to modes 1, 2, 4 or 6. Note that the buttons act as a toggle. For example, pressing RGB BUTTON 5 again will make mode 5 accessible to CV modulation. Release the MOD button. TETRACHORDS | USER GUIDE PAGE | 139...

  • Page 140: (Ii) Midi Out

    MOD button. Press RGB BUTTON 5 to select MOD 5 as the physical input Use RGB BUTTON 8 to select trigger input. TRIGGER The AMOUNT 2 LED blinks to indicate the trigger setting. (cont.) TETRACHORDS | USER GUIDE PAGE | 140...
  • Page 141 LEFT and active. RIGHT buttons. Press RGB button 2 to enable CV control of MIDI channel 2. Incoming triggers now cycle the active MIDI OUT channel between MIDI channel 1 and 2. (cont.) TETRACHORDS | USER GUIDE PAGE | 141...
  • Page 142 Press RGB button 1 to enable CV control of MIDI channel 9. Release the MOD button. Incoming triggers now cycle the active MIDI OUT channel. MIDI CHANNEL 1 MIDI CHANNEL 2 MIDI CHANNEL 9 MIDI CHANNEL 1 TRIGGER TETRACHORDS | USER GUIDE PAGE | 142...

  • Page 143: (Iii) Rev

    Press RGB BUTTON 2 to select MOD 2 as the physical input Use RGB BUTTON 8 to select unipolar (0 to 5v) input. UNIPOLAR (0v to 5v) The AMOUNT 2 LED pulses right to indicate the unipolar setting. (cont.) TETRACHORDS | USER GUIDE PAGE | 143...
  • Page 144 Press the REV 1 BUTTON At this point, RGB button 1 illuminates, indicating the incoming CV can set REV 1 on or off. Release the MOD button. TETRACHORDS | USER GUIDE PAGE | 144...

  • Page 145: (Iv) Vel Level

    Use RGB BUTTON 8 to select bipolar (-5v to 5v) input. BIPOLAR (-5v to 5v) The AMOUNT 2 LED oscillates to indicate the bipolar setting. Press and hold SHIFT then turn the AMOUNT/VEL AMOUNT knob (cont.) TETRACHORDS | USER GUIDE PAGE | 145...
  • Page 146 50% and highest 12.5% of values from CV control. Incoming CV can now set the MIDI velocity level to between 50% and 87.5% of the MIDI velocity range. Release the MOD button. TETRACHORDS | USER GUIDE PAGE | 146...

  • Page 147: (V) Next Pattern(Mod 6 Default)

    Type of input: Next Pattern Targeted Settings: Next PATTERN modulation is enabled by default. When a CV trigger is received on MOD 6, the next PATTERN, if there is one, will play. (cont.) TETRACHORDS | USER GUIDE PAGE | 147...
  • Page 148 LATCH also works as a utility to make button combinations less cumbersome. UI LOCK Lock the UI by tapping LATCH when the Tetrachords’ interface is in one of its non-standard modes. E.g. press SHIFT + PROG/MIDI CC for MIDI CC mode, then tap LATCH to lock the UI.
  • Page 149 This feature makes it possible to synchronize the timing of multiple simultaneous changes. EXAMPLE Initialise the Tetrachords then press and hold the LATCH button. Turn the TETRACHORD 1 knob to MIN. Press RGB buttons 1 & 3. Release the LATCH button.
  • Page 150 Press PATTERN plus the RIGHT button to By default, the LATCH LED is illuminated, indicating that the UI is latched to playback. Tap the LATCH/MIDI OUT button. Press the RIGHT button to navigate to the next pattern. TETRACHORDS | USER GUIDE PAGE | 150...
  • Page 151 Latch UI Lock Lock the UI by tapping LATCH when the Tetrachords is in one of its non- standard modes. E.g. press SHIFT + PROG/MIDI CC for MIDI CC mode, then tap LATCH to lock the UI. It’s now possible to release the LATCH button and edit MIDI CC parameters;...
  • Page 152 Link Overview Details TETRACHORDS | USER GUIDE PAGE | 152...
  • Page 153 Disting Ex Press the ENCODER BUTTON to activate/de-activate the connection for the selected track. When i2c is activated, the LED corresponding to the connected device will assume the colour of the selected TRACK. TETRACHORDS | USER GUIDE PAGE | 153...
  • Page 154 Appendix 1 - CONFIG.TXT TETRACHORDS | USER GUIDE PAGE | 154...
  • Page 155 Acknowledgements TETRACHORDS | USER GUIDE PAGE | 155...
  • Page 156 (cont.) TETRACHORDS | USER GUIDE PAGE | 156...
  • Page 157 A bright blue pill indicates the control PATTERN i.e. Bright red on the prototype. the PATTERN linked to the controls on the Tetrachords faceplate. Note: the CTRL text has been added to this guide for clarity. It does not appear on the faceplate.
  • Page 158 TETRACHORDS | USER GUIDE PAGE | 158...
  • Page 159 TETRACHORDS | USER GUIDE PAGE | 159...
  • Page 160 CYC LE I NST RUME N TS ADDRESS 3/26 Venning St Everton Park QLD 4053 Australia CONTACT info@circleinstruments.com www.circleinstruments.com...
  • Page 161 TETRACHORDS | USER GUIDE PAGE | 161...

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