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JUST FRIENDS: A Technical Map

JUST FRIENDS generates six correlated slopes with a shared set of parameters. Slopes may be configured to be AR/ASR/ARSR envelopes with related durations, quadrature & tempo-synced LFOs, polyrhythmic clocks or LFOs, PWM gates and VCOs, a staircase waveform generator, a slew limiter, overtone/undertone/justly intoned waveshaped VCOs, an additive synthesis harmonic oscillator, a subharmonics generator, tuned but timbrally distinct impulse-train VCOs, internal-LPG-processed oscillators, an internal FM synthesizer, a noise generator, and more!

Mode Maps

Standard Modes

sound shape
transient Impulse-Train VCOs, Pitch Division and Subharmonics Generator Triggered AR Envelopes, Trigger Skipping, Clock Division, Rhythm Modulator and Accent Generator
sustain Trapezoid VCOs and PWM Tracking Gated ASR Envelopes, Gate Delay, Vactrol Memory, Gate-to-CV-Sequence Converter
cycle Waveshaped VCOs, Sync Sounds, Additive Synthesis and Harmonic Oscillator, Chord Generator Looping Envelopes & Temporally-related LFOs, Quadrature LFOs, Phasing Patterns, Polyrhythm Generator, Clock Division/Multiplication Generator, Staircase Sequences and Chaotic Waveform Generator

RUN Modes

sound shape
transient Impulse-Trains, Subharmonics, and Sync Chaos (SPILL) AR Envelopes w/ Retrigger Control (SHIFT)
sustain Lowpass-Gated VCOs & Polyphonic Synthesis (PLUME) ARSR Envelopes w/ Sustain Level Control, Slew Limiting (STRATA)
cycle 2-Operator FM Synthesis & Noise Generator (FLOOM) Envelope and Gate Burst Generator (VOLLEY)

Table of Contents

  1. Specifications
  2. Overview and Block Diagram
  3. Slope Timing
  4. Slope Shaping
  5. range switch
  6. mode switch and TRIGGER Inputs
  7. Frequency Modulation
  8. Making Modulation: Control-rate Techniques
  9. Making Sound: Audio-rate Techniques
  10. RUN Modes
  11. Firmware Update
  12. Calibration & Factory Reset
  13. Warranty

Specifications

  • 14HP
  • 30mm depth
  • 96mA @ +12V
  • 30mA @ -12V

Overview and Block Diagram

JUST FRIENDS is made up of 6 slope generators with shared parameters. The generators are named IDENTITY (a.k.a. 1N), 2N, 3N, 4N, 5N, and 6N. The name "slope generator" is used here instead of "envelope generator" or "impulse generator" in order to remain agnostic as to the use-case: the slopes' use in a modular synthesis context is determined by the rate at which the slopes are excited, whether they are triggered, gated, or looping, and the speed of each slope.

The mode switch determines how the slopes are excited via the TRIGGER (IDENTITY,...,6N) inputs:

The range switch determines the range of speeds (a.k.a. timebase) for the slopes:

  • shape range: minutes to milliseconds (control voltage rate)
  • sound range: milliseconds to microseconds (audio-rate, aka Hz to kHz)

The various combinations of these two switches enable distinct use-cases. The mode maps at the start of this document outline some of the possibilities.

All 6 slope generators share the same interface:

query 'slope's index'

  • TRIGGER inputs (IDENTITY,...,6N) excite slopes according to the mode switch.

  • TIME & INTONE together determine each slope's speed according to the slope's index and the range switch.

  • [RAMP] sets the balance of rise-time and fall-time (like BARREL on MANGROVE) for each slope while leaving the total speed of the slope unaffected.

  • [CURVE] applies waveshaping to bend the linear slopes into various curvatures.

All slopes share the same RAMP & CURVE settings, while the speeds of the slopes are linked proportionally via TIME & INTONE. This combination of TIME & INTONE is central to JF's architecture as it ties the 6 slope generators together: TIME determines the speed of the IDENTITY slope generator, and INTONE determines the ratio of each subsequent slope generator's speed to IDENTITY's speed.

The next sections explain these controls in more detail, but you can jump to the mode maps to explore specific synthesis techniques instead!

JUST FRIENDS Block Diagram

Slope Timing

The speed of each slope generator is determined by a combination of TIME & INTONE. FM provides an additional layer of control, discussed separately.

TIME & IDENTITY

TIME determines the speed of the IDENTITY slope. With TIME fully counterclockwise (CCW), the speed of IDENTITY is at its slowest. Turning TIME clockwise (CW) increases the speed of the IDENTITY slope.

The range switch sets the minimum and maximum speeds on either end of the TIME knob:

  • shape: minutes to milliseconds, from CCW to CW
  • sound: milliseconds to microseconds (a.k.a. Hz to kHz), from CCW to CW

The value of the TIME CV input is added to the TIME knob. The CV input is a highly accurate, exponential input: a 1V increase at the TIME input results in the speed (or frequency) of IDENTITY doubling. As such, the TIME CV input is labeled "v/8," short for "1V/8ve" or "one-volt-per-octave." In shape range, this input is useful for accurately changing note durations (e.g. transforming a quarter-note envelope into a dotted eighth note) and precise timing shifts in LFO rates. In sound range, this input is used for (micro)tonal VCO sequencing or timbral control, depending on the position of the mode switch.

INTONE & the 'N's

INTONE sets the ratio of each of the 2N-6N slope speeds to the IDENTITY speed, where each slope is affected proportionally to its index (2,3,...,6). INTONE is so named due to its relationship to just intonation: setting pitches based off of small-integer ratios.

With INTONE at noon, all speeds are identical.

  • As INTONE turns CW, the speed of each slope besides IDENTITY increases, with the size of the change proportional to the index of the output. This means that 6N will increases its speed the most, while 2N will speed up the least. Once INTONE is fully CW, the 2N slope speed will be double IDENTITY's speed, 3N will be three times IDENTITY's speed, and so on.
  • As INTONE turns CCW from noon, the speed of each slope will instead decrease proportionally to its index, meaning 6N will decrease its speed the most and 2N decreases its speed the least. IDENTITY remains unaffected. Once INTONE is fully CCW, 2N will be precisely 1/2 the speed of IDENITY, 3N will be 1/3 the speed of IDENITY, and so on.

When the INTONE knob is at noon, sweeping the INTONE CV input from -5V to +5V sweeps the speeds from 1/N x IDENTITY to N x IDENTITY. INTONE CV is added to the position of the knob. The knob has a special shaping to enable finer control around noon.

Slope Shaping

RAMP & CURVE set the shape of envelopes and LFOs or the waveform & timbre of VCOs. When first experimenting with either RAMP or CURVE, keep the other at noon to gain better aural intuition for the effect of each control independently.

RAMP sets the balance between rise-time and fall-time in proportion to the duration of each slope without affecting the slope duration. CURVE applies curvature to the rise and fall portions of each slope without affecting their durations.

In shape range, these two parameters control the shape of generated modulation. In sound range, they control the timbre of sound generated by JUST FRIENDS.

RAMP

RAMP controls the balance of rise-time to fall-time as proportions of the total slope duration. As RAMP increases, the ratio of rise-to-fall increases (rise becomes longer, fall becomes shorter). Sweeping the knob from fully CCW to fully CW sweeps the slope shapes from instant attack/long release sawtooths to equal attack/release triangles to long attack/instant release ramps.

When the RAMP knob is at noon, sweeping the RAMP CV input from -5V to +5V is equivalent to sweeping the knob from fully CCW to fully CW. RAMP CV is added to the RAMP knob.

CURVE vs. RAMP{ width=75% }

CURVE

CURVE affects the shape of slopes as they rise and fall without affecting the durations of either stage. It takes the linear slopes determined by TIME, INTONE and RAMP and applies a lookup table to bend them into other shapes without affecting the timing. Fine shapes are available with continuous blending between them.

CURVE waveshaping

  • With CURVE at noon, the slopes are perfectly linear. This position is ideal for creating ramps, sawtooths, and triangles according to the position of the RAMP knob.
  • Turning CURVE CW from noon deforms the slopes into exponential curves. Exponential curves change slowly at the start of each phase and increase their rate of change as the phase progresses.
  • When CURVE reaches fully CW, the slopes become sinusoidal (i.e. sine waves).
  • Turning CURVE CCW from noon deforms the slopes the other way into logarithmic curves, which change quickly at the start of the rise or fall stage, and then decrease their rate of change as the phase progresses.
  • Eventually, once CURVE reaches fully CCW, it makes rectangular shapes. The slope goes to its maximum immediately at the start of its rise phase and stays there until the end of its rise phase. Once the fall phase begins, the slope falls to its minimum immediately and stays there for the duration of its fall phase. The pulse-width is determined by the RAMP control. As a result, in cycle mode, with CURVE fully CCW, RAMP becomes an audio-rate pulse-width modulation input.

When the CURVE knob is at noon, sweeping the CURVE CV input from -5V to +5V is equivalent to sweeping the knob from fully CCW to fully CW. CURVE CV is added to the CURVE knob.

RAMP sweeps at different CURVE settings

The range switch: Timebase, Levels, MIX, FM

The range switch significantly affect the synthesis use cases by affecting the following parameters:

  • Slope generator timebase (range of TIME knob)
  • Unipolar/bipolar slope generator output
  • MIX jack functionality
  • FM AC/DC-coupling

The most important action of the range switch is setting the timebase of the slope generators, as this radically alters how each mode is used. The other changes set by the range switch are implemented in order to reflect the different use-cases for JUST FRIENDS as an audio-rate sound source vs. a control-rate modulation source.

The range switch does not change any of the functionality determined by the mode switch (transient, sustain, cycle), however it can be helpful to think of each pairing individually as the meaning of mode changes from control rate to audio rate.

shape

  • Slope generator timebase: minutes to milliseconds (control-rate)
  • Slope generator output levels: 0-8V, ideal for envelopes and modulation capable of sweeping parameters over wide ranges, as well as generating triggers/gates capable of exciting any trigger/gate input, plucking lowpass gates, and pinging filters.
  • MIX jack behavior: Each slope's output value is divided by its index. The MIX jack then outputs the largest of the resulting values (analog max or "OR"). IDENTITY is divided by 1 (unaffected), 2N is divided by 2, 3N divided by 3, and so on. This provides a unique modulation source otherwise requiring a large patch.
  • FM INPUT jack is DC-coupled, allowing for static linear shifts in speed.

Individual scaled slopes{ width=50% }Analog max slope sent to MIX jack{ width=50% }

sound

  • Slope generator timebase: milliseconds to microseconds, a.k.a. Hz to kHz (audio-rate)
  • Slope generator output levels: -5V to +5V, creating typical Eurorack 10V peak-to-peak audio signals.
  • MIX jack behavior: The MIX jack creates an equal mix of all the current slopes, limiting the final amplitude to ~15V peak-to-peak w/ tanh shaping.
  • FM INPUT jack is AC-coupled so frequency modulation won't affect underlying pitch.

The mode switch and TRIGGER Inputs

The mode switch determines how the TRIGGER inputs excite the corresponding slopes. Each mode has very different synthesis use-cases depending on the timebase of the slopes determined by the range switch.

The TRIGGER inputs for the IDENTITY-6N slopes are located directly above their corresponding output jacks. Depending on the position of the mode switch, the TRIGGER inputs may be gate-sensitive.

The threshold for the inputs is around 1V. LFOs, audio rate oscillators, and other modulation sources can be used as trigger/gate inputs as well as traditional trigger/gate sources.

Trigger and gate responses for the modes

transient mode: Triggered AR Slopes

Each slope generator becomes an attack-release (AR) generator. A trigger to a receptive slope will initiate the attack phase, in which the slope slews to its maximum. This is immediately followed by the release phase.

This mode is not gate-sensitive. Gates are converted to triggers on their rising edge.

Incoming triggers are ignored while a slope generator is active. Once the slope generator reaches the end of the release phase, it becomes receptive to triggers again (finer retrigger control is available in SHIFT).

  • In transient/shape, the slopes become AR envelope generators excited by their corresponding TRIGGER inputs.
  • In transient/sound, the slopes become impulse-train VCOs. An external audio-rate clock source (eg a MANGROVE VCO) must be patched to the TRIGGER inputs to drive the impulse-train VCOs.

sustain mode: Gated ASR Slopes

Each slope generator becomes a gated attack-sustain-release (ASR) generator. This mode is gate-sensitive; triggers are interpreted as short gates.

When a gate input goes high, the corresponding slope slews upward towards its maximum value. If the gate is long enough, the slope will reach its maximum and sustain there until the gate goes low.

When the gate goes low, the slope will begin slewing towards its minimum value. If the slope has not yet reached its maximum when the gate goes low, the slope will still start slewing towards its minimum regardless.

If a new gate arrives before a slope reaches its minimum, the slope will immediately resume rising from its current value.

  • In sustain/shape, the slopes become ASR envelopes. Gates patched to the TRIGGER inputs excite the slopes.
  • In sustain/sound, the slopes become trapezoid impulse-train VCOs. An external audio-rate clock source (like another VCO) must be patched to the TRIGGER inputs to drive the trapezoid impulse-trains. These impulse-trains are "trapezoids" because they will track the pulse-width of the clock source for an additional method of timbral control.

cycle mode: Looping Slopes w/ Phase Reset

Each slope generator becomes an oscillator by effectively using an end-of-cycle pulse to retrigger itself. This forces the slopes to loop endlessly.

Each TRIGGER input will reset the oscillator to the start of its cycle (hard-sync).

This mode is not gate-sensitive. Gates are converted to triggers on their rising edge.

  • In cycle/shape, the endlessly looping slopes are LFOs! CURVE & RAMP control wave shape. The TRIGGER inputs are useful for syncing LFOs to the same phase, spreading LFOs into quadrature structures, and creating polyrhythmic/phasing patterns.
  • In cycle/sound, the endlessly looping slopes become waveshaped VCOs. The TRIGGER inputs are used to sync the VCOs to other oscillators for spectral effects.

TRIGGER Input Normalling

Each trigger input is normalled into the trigger gate input to its left. This means that a trigger patched to an input will cascade to the other unpatched inputs to its left until it reaches a patched trigger input. Inserting another trigger/gate source (or dummy cable) into a trigger input will break the corresponding normal.

Examples:

  • A trigger patched to 6N (while no other trigger inputs are patched) will excite all 6 inputs.
  • With one trigger patched to 6N and another patched to 2N, the 6N trigger will cascade to 5N, 4N, and 3N. The 2N trigger will excite 2N and IDENTITY.

Frequency Modulation

There are 3 primary methods of FM:

  • Exponential FM, via the TIME(v/8) jack
  • INTONE FM, via the INTONE jack
  • Combo INTONE & linear through-zero FM, via the FM INPUT jack.

For the purposes of this discussion, it will be assumed that the slope generators are in cycle/sound in order to facilitate discussion of frequencies, rather than durations. FM effects in all other modes should also be explored for their unique spectral and temporal effects.

TIME(v/8) jack

Any signal applied to this jack, AC or DC, audio-rate or control-rate, will affect the frequency (or equivalently, duration) of all slopes exponentially: a +1V increase at this jack will result in the frequency of all slope generators doubling. The oscillators maintain their harmonic relationships.

The range of the TIME jack is roughly -2V to +5v. Voltages outside this range will be clamped at the limits.

INTONE jack

Any signal applied to this jack, AC or DC, audio-rate or control-rate, will affect the frequency (or, equivalently, duration) of each slope generator according to its index: IDENTITY is unaffected, 2N is affected the least, and 6N is affected the most. This signal is added to the INTONE knob.

FM knob & FM INPUT jack

The FM INPUT jack is the input for a frequency modulation source. The FM knob controls depth (a.k.a. index) of modulation by the FM INPUT signal for each slope generator.

With the knob at noon, no FM is applied to any of the slopes (the FM INPUT jack is ignored).

Turning the FM knob clockwise increases the depth of the modulation linearly applied to all slopes equally.

Turning the knob counterclockwise from noon increases the depth of the modulation applied to each slope generator in the INTONE style, i.e. in proportion to each channel's index (IDENTITY is unaffected, 2N the least affected, 6N the most affected).

The FM knob thus controls whether the FM INPUT jack is linearly applied to the INTONE parameter (CCW) or linearly applied to the TIME parameter (CW), as well as the depth of the FM INPUT applied to either parameter.

When using audiorate FM and the MIX output jack, turning the FM knob towards TIME results in 'deeper' and more traditional sounding FM, while the INTONE direction will have more bass as the fundamental (IDENTITY) remains unaffected. This can be useful for FM bass sounds which can often lack low-end.

FM INPUT jack: shape range

The linear FM INPUT jack is DC-coupled in shape range. It can be used with constant DC offsets for linear speed and duration shifts. To ensure the accuracy of the INTONE knob, keep the gray FM knob set to noon when no FM input is being applied.

FM INPUT jack: sound range

The FM INPUT jack is AC-coupled (i.e. a DC-blocker is applied to the input) in order to achieve high-quality, linear, through-zero frequency modulation. The knob has no effect when the FM INPUT jack is disconnected.

Making Modulation: Control-Rate Techniques

Use this map to find a control-rate technique that interests you!

mode technique
transient Triggered AR Envelopes
Trigger Skipping
Clock Division
Rhythm Modulator and Accent Generator
Precise Duration Sequencing
sustain Gated ASR Envelopes
Gate Delay
Vactrol Memory
Gate-to-CV-Sequence Converter
cycle Temporally Related LFOs
Synchronizing LFOs
Quadrature/Phase-Shifted LFOs
Phasing LFOs and Polyrhythmic Patterns
Staircase Sequences and Chaotic Waveforms

transient/shape: Triggered AR Envelopes

JUST FRIENDS turns the slopes into 6 attack-release (AR) envelope generators. CURVE & RAMP control envelope shape, while TIME & INTONE control envelope duration. Capable of extremely fast, percussive envelopes, subtle modulations that take minutes to complete, and everything in between, this mode allows for animating your patches across the micro- (individual events and hits), meso- (gestural and phrase) or macro- (movement and composition) time-scales.

  • With all knobs at noon, patch a trigger (or gate) into 6N to begin. When a trigger arrives, all 6 envelope generators will start since each trigger input is normalled to the trigger input to its right.
  • Now patch a second trigger source into 3N, breaking the normalling of the 4N trigger into the 3N trigger input. When the 6N trigger goes high, slopes 6N, 5N, and 4N will start, but not the others. When the 3N trigger goes high, the 3N, 2N and IDENTITY envelopes will rise. This makes two sets of three identical AR envelope generators. Now turn INTONE to create variation within each set of three envelopes.

transient/shape: Trigger Skipping

When a slope generator is active, all incoming triggers will be ignored until after it completes its entire cycle (for specific control over the retrigger point, see SHIFT). This behavior can be utilized to create complex rhythmic modulations and clock divisions as well as generate accent patterns from a single trigger stream:

  • Send a trigger stream that is faster than the envelope time.
  • Use INTONE to set the receptive AR envelope generators to different durations.
  • Now, some envelope generators will still be in progress when a new trigger arrives, while others will have completed. The envelopes that have completed will retrigger, while the envelopes that are still in progress will skip triggers.

transient/shape: Clock Division, Rhythm Modulator and Accent Generator

Because INTONE determines the length of envelopes, it also determines which envelopes will retrigger versus which envelopes will skip triggers. If the input trigger stream is at a constant rate, adjusting INTONE will set different clock divisions for the associated outputs.

  • Start by patching a steady 16th-note trigger stream (aka 4 p.p.q.n.) to 6N with nothing patched to the other TRIGGERs. Set TIME so that the IDENTITY envelope is just shorter than the trigger stream period.
  • Now, turn INTONE fully CCW, so that 2N is twice as long as IDENTITY, 3N is three times as long as IDENTITY, and so on.
  • If the trigger stream is considered to be 16th-notes, then 2N will output an envelope on the 8th-notes (every other input pulse), 3N will output a trigger every dotted 8th note (every third input pulse), 4N will output a trigger every quarter note (every fourth input pulse), 5N will output a trigger every quarter note+16th note (every 5th trigger pulse), and 6N will output a trigger every dotted quarter note (every 6th input pulse).

INTONE can also be used to derive triplet trigger streams from a faster clock.

  • Send in a very fast trigger stream to 6N.
  • Set TIME so that IDENTITY takes just under 13 trigger pulses to complete.
  • Set INTONE fully CW, so that 2N is twice as fast, 3N is three times as fast, and so on.
  • If IDENTITY is considered to be a half note, then 2N is quarter note, 3N is a triplet quarter note, 4N is an 8th-note, and 6N is a triplet 8th-note.

Modulating INTONE becomes a way of changing the clock divisions for each output with CV. This can be used to great effect to generate irregular rhythms from a single, periodic clock stream. If CURVE is fully CCW, the output slopes will be rectangular, resulting in simple clock pulses derived from the input clock.

The trigger-skipping behavior can also be paired with a rhythmic, non-uniform input trigger pattern to create interesting, unexpected accent patterns. The output rhythm or accent pattern will depend on the position of INTONE and the spacing of the input triggers. Modulating INTONE transforms how each output rhythm is derived from the input rhythm.

If TIME and INTONE are set so that IDENTITY is a quarter note, 2N is an eighth note, and 4N is a 16th note, then IDENTITY will output a slope whenever two triggers are separated by at least a quarter note, 2N will output an envelope whenever two triggers are separated by at least an eighth note, and 3N will output a trigger whenever two triggers are separated by at least a 16th note. INTONE will change the spacing between triggers needed for each envelope to become retriggerable. This can be used especially effectively to create an accenting envelope at the start of a burst of triggers.

transient/shape: Precise Duration Sequencing

Typically, "one-volt-per-octave" inputs are used to sequence oscillator pitch. However, in shape range, even though the TIME CV input does not control pitch, it still is one-volt-per-octave! This means that a 1V increase at the input will result in the IDENTITY envelope becoming exactly twice as fast.

In transient/shape, this can be utilized to create rhythmically accurate transformations of note durations:

  • Send 0V into TIME CV.
  • Use the TIME knob to set IDENTITY's duration to a whole note.
  • +1V into TIME will set IDENTITY to a half note, +2V sets it to a quarter note, +3 to an 8th, +4 to a 16th, and so on.
  • This will have a knock-on effect on the other slope durations. For instance, if INTONE is set so that an output is a dotted 8th note, a +1V increase at TIME will transform it into dotted 16th. Similarly, if INTONE is set so that a slope is a triplet 8th, then a +1V increase will transform it into a triplet 16th.

sustain/shape: Gated ASR Envelopes

JUST FRIENDS turns into 6 attack-sustain-release (ASR) envelope generators. RAMP and CURVE control the shape of the envelopes' A/R phases, while TIME and INTONE control the speed of the A/R phases.

Patching gates to the TRIGGER inputs will cause the envelope generators to slew to their maximum and hold there while the gates are high, and then slew to the minimum when the gates go low. If a gate changes state before the envelope reaches its minimum or maximum, it will simply change direction from its current location. The envelopes can be thought of as slew-limiters that go between two states: high and low.

Although the six ASRs can be used independently, using them together can allow for interesting macroscopic control of an entire patch. For instance, patching a single gate to 6N with no other TRIGGER inputs patched enables creating transitions across an entire patch that start simultaneously but take varying amounts of time to complete according to INTONE.

sustain/shape: Gate Delay

If RAMP is set to fully CW and CURVE is set to about 3 o'clock, JUST FRIENDS can be used as a gate delay. When an input gate goes high, the receptive slope will begin changing slowly at first since the CURVE is exponential and the rise-time is the entire duration of the slope. When the slope does finally ramp up, it will do so quickly, and then hold at the maximum level, resulting in a delayed version of the input gate (though it will go low as soon as the input gate goes low).

TIME will set the base delay-time for IDENTITY, while INTONE will set the delay times for 2N-6N.

With a single gate connected to consecutive TRIGGER inputs via normalling, this can be an effective tool for strumming multiple envelope generators or striking multiple LPGs in quick succession.

sustain/shape: Vactrol Memory

In sustain/shape, envelope speed can interact with RAMP to create a form of "memory" similar to the vactrol memory effect: this memory adjusts how long each gate interacts with the subsequent gates. Changing RAMP, envelope speed, input gate lengths, and the rate of input gates will affect the form of gate memory. If envelopes don't have enough time to reach their minimum between gates, or the maximum during a short gate, then the "memory" is the level of the slope when the input gate changes states.

The effect is most notable with RAMP set CCW and using bursts of short gates arriving faster than the envelope time to excite a slope. When this happens, the envelopes don't have time to reach their minimum before a new gate arrives, resulting in each subsequent envelope initiating from a higher and higher level. Gates must be spread out in order for the envelope to fall back to its low state.

Turning RAMP CW will increase the rise-time so that it takes longer to get into the high state. If the input gates have relatively short pulse-widths, a slope may not reach its sustain phase before the first trigger/gate goes low. When a dense stream of gates occur though, each short gate or trigger will push the slope further toward its maximum.

This is very useful for creating a crescendo effect from a simple stream of triggers or short gates. The denser the stream of gates, the greater the level of the envelope! Rarefying the gate stream will result in the envelope settling back down to a lower level each time.

Turning RAMP further and further CW requires a denser - or longer - trigger stream to complete the crescendo. Adjusting gate-width will also change how long it takes to complete the crescendo; longer gates will allow the slope generator to reach a higher level each trigger.

The longer the duration of the rise phase, the longer a slope generator will remember being in the low state. Similarly, the longer the duration of the fall-phase, the longer the slope generator will remember being in the low state. RAMP can be thought of as controlling the balance between which state is remembered: high when RAMP is CCW, versus low when RAMP is CW.

sustain/shape: Gate-to-Sequence Converter

When CURVE is set fully CCW to square curvature, the TRIGGER inputs can be used to turn the MIX output into a "priority CV sequencer." This can be used to derive a single CV sequence from a set of rhythmic gate patterns.

"Priority" means that each TRIGGER input has a different priority: the lowest-index TRIGGER input that is held high will determine the CV value sent out of the MIX jack. This is because the MIX output in shape range is created by dividing the current level of each slope by its index, and then outputting the maximum of the resulting 6 values. When CURVE is fully CCW, the MIX output will be a staircase sequence since there will be no slew time whenever the gate with highest priority (lowest index) changes states.

  • If the IDENTITY slope is held high, then the output will be 8V, regardless of the other slopes are doing.
  • If the IDENTITY slope is low and 2N is held high, then the output will be 8V/2 = 4V, regardless of what 3N-6N are doing.
  • If the IDENTITY and 2N slopes are low, and the 3N slope is high, then the output will be 8V/3 = 2.66V, regardless of what 4N-6N are doing... and so on.

As such, sending gates into the TRIGGER inputs will select one CV value out of 6 possibilities depending on the lowest-index TRIGGER that is held high!

If the MIX sequence is attenuated and sent through a quantizer, independent rhythms can be used to select different notes from a chord. Try using sparser gate streams for the lower TRIGGER inputs and denser streams for the upper TRIGGER inputs. If the rhythmic patterns have different lengths or are changing over time, the resulting quantized-MIX output will be an ever-evolving generative sequence! Patching the sequence through attenuators/mixers/VCAs for further shaping will allow for another level of modulation and evolution of the CV sequence.

Playing with gate-widths can also change the sequence as some gates go low before other lower priority (higher-index) gates go low, resulting in note changes between clock pulses.

Pairing a steady clock with a clock divider, linear-feedback shift register, or other clock modulator can be a great way of deriving multiple gate streams from a single input.

Adjusting CURVE away from fully CCW will add some slew to the voltage transitions at the MIX output when the lowest-index slope is released or activated. Rise and fall slew times are controlled by TIME, INTONE and RAMP.

Driving the gate inputs with fast, periodic gate streams will turn the MIX out into a staircase waveform. Try patching various outputs of a clock divider or multiplier with gate outputs into all 6 JF gate inputs. Swapping clock streams from one input to another will change the wave shape. Try using logic modules to combine gate streams for some of the inputs into new gate streams for other inputs - COLD MAC can achieve all standard logic operations like OR, AND, XOR, NOR and NAND. Other bit generation and bit processing techniques are ripe for exploration!

cycle/shape: Temporally-related LFOs

In cycle/shape, JF becomes six LFOs with controllable temporal relationships.

TIME determines the frequency of the IDENTITY LFO: low frequencies occur with TIME fully CCW, and high frequencies with TIME fully CW.

INTONE defines the frequency relationships of LFOs 2N-6N to IDENTITY, allowing the LFOs to spread from 1/N times the frequency of IDENTITY to N times the frequency of IDENTITY (where N is the INDEX of a given LFO). INTONE can be used to create extended phasing patterns or precise temporal divisions.

The slowest possible LFO will come from 6N when INTONE and TIME are both fully CCW, accompanied by sending -2V into the TIME jack. Also, FM can STOP the oscillator all together for infinite duration!

cycle/shape: Synchronizing LFOs

To re-synchronize the start point of all 6 LFOs, send a trigger to the 6N trigger input with nothing patched to the other trigger inputs. When INTONE is at noon, this results in all LFOs becoming perfectly in sync with each other, rising and falling identically. With INTONE away from noon, the trigger into 6N resets the phasing pattern to its start. Flicking the MODE switch out of cycle and then back into cycle will also quickly reset the phase of all LFOs.

cycle/shape: Quadrature/Phase-Shifted LFOs

With INTONE at noon, all LFOs will have identical frequency, but not necessarily the same phase - they may be shifted in time, but oscillating at the same rate.

Adjusting INTONE away from noon and then back to noon will result in the 6 LFOs becoming out of phase. As INTONE moves away from noon, the LFOs speed up and slow down at different rates (defined by their INDEX). As INTONE returns to noon, the oscillators return to the same frequency, but will not necessarily be at the same point in their cycles. Because the frequencies are now identical, the oscillators will remain out of phase with each other by the same amount.

Sending triggers to the different inputs will allow you to adjust the phase-shift of the LFOs by directly restarting them in time.

cycle/shape: Phasing LFOs and Polyrhythmic Patterns

When INTONE is away from noon, the LFOs will create phasing patterns due to the different frequencies of each LFO. When CURVE is fully counterclockwise (square waveshape), these LFOs become polyrhythmic trigger/gate/clock streams. Gate/pulse-width is controlled via the RAMP knob.

When INTONE is fully clockwise, the phasing pattern will perfectly repeat every time IDENTITY completes one cycle, since the duration of each LFO evenly divides IDENTITY's duration (their frequencies are integer multiples of IDENTITY's). This results in a typical "clock multiplier" pattern, where IDENTITY is the leader LFO: each other LFO repeats N times for every 1 cycle of IDENTITY.

If IDENTITY's duration is considered to be a quarter note, then 2N is an 8th note, 3N is a triplet 8th note, 4N is a 16th note, and 6N is a triplet 16th note.

If the LFOs are out of phase when INTONE reaches fully clockwise, the 2N-6N LFOs will not be at the start of their cycles when IDENTITY reaches its start. They will be shifted in time in relationship to IDENTITY. This shift will remain identical for each repetition of IDENTITY. The start points can be resynchronized via the trigger inputs.

When INTONE is fully counterclockwise, the phasing pattern will perfectly repeat every 60 cycles of IDENTITY, since 60 is the least common multiple of 1,2,3,4,5,6. Think of this as a "clock divider", where IDENTITY is the leader clock. Unlike most clock dividers though, JUST FRIENDS is capable of phased modulation, not just clocks! Furthermore, the LFOs can be shifted in time by adjusting INTONE away from CCW and then quickly back, or by sending triggers to a subset of the TRIGGER inputs. Sending a trigger to 6N with nothing patched to the other inputs will reset all LFOs' phasing modulation into a traditional clock division timing.

When INTONE is away from noon but not at either extreme, much more drawn out phasing patterns will occur due to the non-integer timing ratios. These can be made more rhythmic by sending in regular but slow pulses into 6N (or into a combination of multiple trigger inputs), resetting the pattern on each pulse.

One useful technique is to patch the output of one of the slower LFOs/clock streams into the trigger inputs of the faster ones (taking advantage of normalization). This will create a pattern that resets all the connected LFOs every time the slower LFO crosses the triggering threshold. Note the CURVE control will have a dramatic effect on the time taken to reach that threshold.

The TIME CV jack can be used to create tempo-accurate shifts in the phasing patterns (e.g. doubling or halving the period of repetition for the entire pattern). A +1V increase at the TIME jack will double the frequency of the entire pattern.

cycle/shape: Staircase Sequences and Chaotic Waveforms

When CURVE is set fully CCW, (square waveshape) the MIX output becomes a stepped sequence. This is because the MIX output in shape range is is created by dividing the current level of each slope by its index, and then outputting the maximum of the resulting 6 values. With CURVE fully CCW, there will be no slew time whenever an LFO goes high or low, so the resulting MIX output is a staircase sequence. The level of the sequence is always determined by the active LFO with lowest index.

  • If the IDENTITY slope is high, then the output will be 8V, regardless what the other slopes are doing.

  • If the IDENTITY slope is low and 2N is high, then the output will be 8V/2 = 4V, regardless of what 3N-6N are doing.

  • If the IDENTITY and 2N slopes are low, and the 3N slope is high, then the output will be 8V/3 = 2.66V, regardless of what 4N-6N are doing.

  • And so on...

When INTONE is set to noon, the LFOs have the same frequency but may be slightly out of phase, resulting in a staircase waveform at the same frequency as IDENTITY.

When INTONE is in an intermediate position, the phasing relationships between LFOs will create a constantly evolving staircase sequence. Try patching this sequence to a pitch input (possibly through offsets/mixers/VCAs and a quantizer first) for generative sequences - or try using it as CV for another parameter on your synthesizer! Resetting the faster LFOs with the gate from one of the slower LFOs will create a more clearly repeating pattern. A periodic external clock source can also be used to reset LFOs and create a discernible pattern.

When TIME is relatively fast, this sequence becomes a staircase waveform generator. Resetting a subset of the slope generators with a trigger will change the waveform. The frequency of the waveform is determined by the repetition period of the whole pattern, so INTONE at fully CW will produce waveforms with the same frequency as IDENTITY.

RAMP will affect the duration of level shifts and overlap between each step. RAMP near CCW means variable height, narrow pulses, while further CW makes IDENTITY dominate the output.

Turning CURVE slightly away from fully CCW will add some slewing. INTONE and TIME will also affect the rate of slewing.

When CURVE is adjusted further away from CCW, the output begins to become a more and more chaotic waveform with slewing, rather than hard transitions between levels.

Making Sound: Audio-rate Techniques

Use this map to find a synthesis technique that interests you:

mode technique
transient Impulse-Train VCOs
Pitch Division and Subharmonics Generator
sustain Trapezoid VCOs and PWM Tracking
cycle Waveshaped VCOs
Sync Sounds
Additive Synthesis and Harmonic Oscillator
Chord Generator

transient/sound: Impulse-Train VCOs

JUST FRIENDS turns into 6 impulse-train VCOs requiring an external VCO to drive the TRIGGER inputs.

  • Every time the input clock source (any oscillator will work) goes high, it excites the slope, which goes from min to max to min.
  • Once the slope reaches its minimum, it rests until the clock source goes high again.
  • The slope generator ignores incoming clock pulses while in the rising and falling state.
  • Since the slope generator is excited at the same frequency as the input oscillator, the output is a repetitive waveform at the same frequency as the input!
  • The shape of the waveform is the shape of the slope followed by a resting phase.

Adjusting the slope speed with TIME & INTONE will adjust the impulse train's timbre rather than its pitch. The pitch is determined by the external oscillator because it sets the rate at which the impulses are repeated.

The duration of each impulse, set by TIME & INTONE determines how much of the period of oscillation is taken up by the impulse, affecting the waveshape that is repeated when driven by an audio-rate signal. This is equivalent to the FORMANT control on MANGROVE, though the sonic result with JUST FRIENDS will have its own unique character due to the CURVE knob and the digital versus analog implementation of the two modules.

RAMP & CURVE provide additional timbral controls including pulse-width modulation via the RAMP control when CURVE is fully counterclockwise.

transient/sound: Pitch Division and Subharmonics Generator

If the duration of an impulse exceeds the clock period, then the first retrigger will be ignored, resulting in two clock periods completing before the impulse gets retriggered. This means that the impulse will only be excited once for every two input clocks pulses: this creates a pitch division down to 1/2 the input clock frequency (dropping an octave).

Similarly, if the impulse duration exceeds two clock periods, than the pitch will divide down to 1/3rd the input clock frequency (three clock cycles must complete before the slope generator can be retriggered).

This series of pitch divisions defines an undertone series. As such, when patching an audio-rate signal to 6N and leaving the other triggers unpatched, INTONE can be used to dial in different subharmonics of the source audio signal for each JF output.

Note that these divisions are possible with all settings of RAMP & CURVE, unlike on MANGROVE (which requires RAMP - aka BARREL be near its minimum). This provides more direct timbral control, but makes multiphonics inaccessible.

Impulse Train TIME Sweep

sustain/sound: Trapezoid VCOs and PWM Tracking

Similar to transient/sound, JUST FRIENDS turns into 6 VCOs driven by external audiorate clock sources. However, because the inputs are now gate sensitive, new timbral possibilities open.

These impulse-trains are "trapezoids" because they will track the pulse-width of the clock source. The slopes will stay high as long as the input VCO remains above the threshold. As such, the input VCO and output trapezoid VCO will have the same pulse-width. Varying the pulse-width of the input VCO will also vary the timbre of JUST FRIENDS. The response is highly interactive between TIME, INTONE, & the source PWM.

MANGROVE is a great clock source for this purpose, with the FORMANT control modulating the width of the JUST FRIENDS trapezoid VCOs.

cycle/sound: Waveshaped VCOs

In cycle/sound, JF becomes a set of 6 audiorate VCOs with sync inputs and waveshaping.

RAMP & CURVE affect timbre, while TIME & INTONE control pitch.

This mode is great for polyphonic patches; additive synthesis with rich timbre; creating justly intoned chord structures; detuned beating patterns and supersaws; self-patched feedback FM & timbral modulation!

TIME & INTONE

TIME sets the fundamental frequency of IDENTITY. The TIME CV jack can be used to (micro)tonally sequence IDENTITY with standard volt-per-octave (v/8) voltage sources, or it can be used at audio rate for exponential frequency modulation.

INTONE determines the frequency/pitch ratio of the other oscillators in relationship to IDENTITY. At noon, all oscillators are at unison (equal frequency). On either side of noon, oscillators become slightly detuned, allowing for supersaws and super-all-the-other-waveforms. Fully clockwise results in a harmonic overtone series of frequencies: 2x, 3x, 4x, 5x, 6x, or, in terms of intervals, up an octave, up an octave and a fifth, up two octaves, up two octaves and a major third, up two octaves and a fifth. INTONE fully clockwise results in an undertone series of frequencies: 1/2x, 1/3x, ..., 1/6x.

Other intervals and frequency ratios are achievable at various intermediate positions of INTONE.

INTONE Sweep

RAMP & CURVE

With RAMP at noon, the CURVE knob interpolates between squares, log-curves, triangles, exponential-curves and sine waves. With CURVE fully counterclockwise, all oscillators are square waves, and the RAMP control becomes a pulse-width control. With CURVE at noon, RAMP interpolates between saws, triangles, and ramps.

CURVE Sweep

RAMP Sweep

RAMP Audio-rate Modulation 1:4 Ratio, Depth Sweep

cycle/sound: Sync Sounds

The trigger inputs act as oscillator reset inputs, creating classic hard-sync sounds you might get from a saw-core VCO. Patch an oscillator into one of these inputs and monitor the corresponding output: sweep TIME to hear the timbral sync effect occurring. Sweeping the pitch of the external sync source oscillator will interact with the TIME control to set pitch & timbre.

Try patching 4N's output to IDENTITY's TRIGGER input; sweep INTONE while listening to IDENTITY. Next, try patching IDENTITY's output to 4N's TRIGGER input (use a dummy cable into 3N o block the triggers from cascading back down to IDENTITY). Sweep INTONE, but listen to 4N this time.

cycle/sound: Additive Synthesis and Harmonic Oscillator

When INTONE is fully CW, CURVE is fully CW, and RAMP is at noon, all the outputs will be sine waves in a harmonic series. Try sending several outputs to different channels of a mixer; adjust the level of each input to create complex waveshapes beyond the typical sine/saw/expo/log waveshapes available via RAMP and CURVE. Adjusting RAMP and CURVE away from their respective positions will brighten the sound and make the individual tones in the series more audible as distinct pitches, rather than a single blended waveform.

When INTONE is turned CCW, the frequencies of the 2N-6N outputs follow an undertone series for the IDENTITY oscillator. With CURVE and RAMP set away from CW/noon respectively, mix these outputs with IDENTITY at low amplitudes to create thick sub-sounds that are spectrally richer than the typical square wave subharmonics available on many synthesizers.

cycle/sound: Chord Generator

When INTONE is fully CW or fully CCW, the outputs can be selectively mixed to create chords.

Here are some common frequency ratios which are helpful (but not necessary!) to know:

Ratio Interval
2:1 (2x) Octave
3:2 (1.5x) Perfect Fifth
4:3 (1.33x) Perfect Fourth
5:4 (1.25x) Major Third
6:5 (1.2x) Minor Third

When using this table, it is useful to remember that dividing or multiplying the numerator or denominator of a ratio by two simply shifts an interval up or down by an octave: 5:4 is a major third, so 10:4 is an octave and major third, while 10:8 is identical to 5:4.

The following tables outline how INTONE can be used to generate triads across JUST FRIENDS' 6 voices. Note that in both tables, 3N, 4N, and 5N always contain all three notes of the triad. Carefully sequencing of TIME in conjunction with INTONE can thus allow you to create chord progressions using just these three outputs.

Major Chords: INTONE CW

The following table gives the intervals and ratios when INTONE is fully CW. Since IDENTITY is the lowest frequency, we will consider that the root note, and tune it to C3.

Output N to IDENTITY Interval above IDENTITY Ratio to N-1 Interval above N-1 Note
IDENTITY 1:1 N/A N/A N/A C3
2N 2:1 Octave 2:1 Octave C4
3N 3:1 Octave+5th 3:2 5th G4
4N 4:1 2 Octaves 4:3 4th C5
5N 5:1 2 Octaves+Major 3rd 5:4 Major 3rd E5
6N 6:1 Two Octaves+5th 6:5 Minor 3rd G5

With INTONE CW and IDENTITY tuned to C, the collection of notes defines a major triad: C-E-G. The root note of the triad will depend on the position of the TIME knob. Various inversions and voicings of a major triad are available via different mixes of the 6 outputs.

Minor Chords: INTONE CCW

The following table gives the intervals and ratios when INTONE is fully CCW. Since 6N is the lowest frequency, we will consider that the root note, and measure intervals above 6N. For comparison with the previous table, we will keep identity tuned to C3.

Output N to 6N Interval above 6N Ratio to N+1 Interval above N+1 Note
IDENTITY 6:1 ~ 3:2 2 Octaves+5th 2:1 Octave C3
2N 6:2 ~ 3:2 Octave+5th 3:2 5th C2
3N 6:3 ~ 2:1 Octave 4:3 4th F1
4N 6:4 ~ 3:2 5th 5:4 Major 3rd C1
5N 6:5 Minor 3rd 6:5 Minor 3rd Ab0
6N 1:1 N/A N/A N/A F0

With INTONE CCW, the collection of notes defines a minor triad: F-Ab-C. The root note of the triad will depend on the position of the TIME knob. Various inversions and voicings of a minor triad are available via different mixes of the 6 outputs.

RUN Modes

The RUN jack presents 6 new modes for JUST FRIENDS, one for each of the 6 standard modes given by the range and mode switches. Some of the modes are extensions of the standard functionality of the given switch pairings, while others are radical alterations.

Plugging a cable into the RUN jack activates the RUN mode associated with the position of the range and mode switches.

Connecting the other end of the RUN cable to a CV source will allow you to control the parameter assigned to the RUN jack depending on the selected mode. The RUN modes can be used with a dummy cable plugged into the RUN jack input - i.e. the other end of the cable is not attached to a CV source. In this case, it is as if there is a 0V source patched into the RUN jack.

sound shape
transient SPILL: Impulse-Trains, Subharmonics, and Sync Chaos SHIFT: AR Envelopes w/ Retrigger Control
sustain PLUME: Lowpass-Gated VCOs & Polyphonic Synthesis STRATA: ARSR Envelopes w/ Sustain Level Control, Slew Limiting
cycle FLOOM: 2-Operator FM Synthesis & Noise Generator VOLLEY: Envelope and Gate Burst Generator

SHIFT (transient/shape): AR Envelopes w/ Retrigger Control

SHIFT extends the standard transient/shape AR envelope generator controls to include control over when slope generators become receptive to retriggers.

Typically in transient/shape, while a slope generator is active, it will ignore all incoming triggers. It does not become receptive to incoming retriggers until the end of its cycle. Entering SHIFT mode by plugging a cable into the RUN jack allows the slope generators to become receptive to retriggers before they reach the end of their cycles. When a slope gets retriggered, it immediately resets to 0V and begins the rise phase (rather than turning around from its current position).

  • With -5V into the RUN jack, the slope generators are always receptive to retriggers.
  • From -5V to 0V into the RUN jack, the retrigger point shifts towards the end-of-rise. For instance, at -2.5V, the slope generators become receptive to retriggers midway through the rise phase.
  • With 0V (or a dummy cable) into the RUN jack, the slope generators can be retriggered after the end of the rise phase.
  • From 0V to +5V, the retrigger point shifts from end-of-rise towards end-of-cycle.
  • With +5V, the retrigger point is end-of-cycle (equivalent to standard transient/shape retrigger behavior). That is, a slope generator does not become receptive to retriggers until it becomes inactive again.

SHIFT can be used to extend the techniques described in transient/shape: Rhythm Modulator and Accent Generator

SHIFT retrigger control

STRATA (sustain/shape): ARSR Envelopes and Slew Limiting

STRATA extends the standard sustain/shape ASR envelope generator to become an attack-release-sustain-release (ARSR) envelope generator. This additionally enables JUST FRIENDS to be used as a 6-output slew limiter.

ARSRs in STRATA

STRATA ARSRs

Typically in sustain/shape, when a gate arrives, slope generators will rise to their maximum, hold as long as the gate is high, and then fall when the gate goes low. Entering STRATA mode by plugging a cable into the RUN jack changes this by segmenting the falling stage into two sub-segments: the initial release segment (release-1) and the final release segment (release-2). These two stages are separated by the sustain stage. This is very similar to the familiar ADSR shape, however the Decay & Release stages share their timing parameter.

As in sustain/shape, the rise and fall times are determined by the combination of TIME, INTONE & RAMP.

The RUN voltage determines the sustain level: the greater the RUN voltage, the higher the sustain level. Release-1 is the amount of time it takes for the falling stage to reach the sustain level from its maximum; release-2 is the amount of time for the falling slope to go from the sustain level to 0V. The only difference from standard sustain/shape is a temporary pause at the sustain level.

Sustain level in STRATA

When a gate is sent to a slope generator, the slope begins sloping towards its maximum (attack). When it reaches its maximum, it immediately begins falling to the sustain level set by the RUN voltage (release-1). When it reaches the sustain level, the slope holds (sustains) there until the input gate goes low. When the gate goes low, the slope continues falling to its minimum (release-2). If a gate is not held high long enough to reach the maximum or the sustain level, the slope will simply resume the falling phase from its current value when the gate goes low.

The sustain level is set by the RUN voltage before the CURVE-waveshaper is applied. As such, the CURVE control has a great affect on sustain level as it bends the linear ramps into exponential and logarithmic curves. This online demo should give you a good sense of the interaction between gate length, RAMP, RUN voltage, and CURVE. The black ARSR envelope shown is the linear slope pre-CURVE waveshaper, while the blue one is post-CURVE waveshaping.

Slew Limiting in STRATA

Because the sustain level in STRATA is determined by the RUN voltage, JUST FRIENDS can be configured to work as a slew limiter (voltage follower) by patching a positive voltage source to the 6N trigger input with nothing patched into the other trigger inputs. This positive voltage source holds all slope generators in their sustain phase. All 6 outputs will be equally held at the same sustain level determined by the RUN voltage.

The voltage to follow should be patched to the RUN input. Changing the voltage at the RUN jack will cause the sustain level to change. When it does, each slope generator will complete the portion of the slope between the old sustain level and the new sustain level.

Since each slope generator may have different speeds according to INTONE, the result is 6 slew limiters which track the same voltage (RUN) but with different time constants. The time constants are determined by the combination of TIME, INTONE, and RAMP.

NB: Don't expect volt-per-octave tracking! The voltage to follow is remapped from (-5V,5V) to (0V,8V) and is subjected to the transformation applied by the CURVE knob.

Having six slew limiters with different time-constants but the same input voltage can be useful in a variety of scenarios. For instance, try patching a random sample+hold/staircase sequence through RUN. Now, the 6 outputs will become versions of the input sequencing with varying degrees of smoothness: outputs with fast time-constants will closely track the sharp discontinuities in the input signal, while outputs with longer time-constants will be more sinusoidal, smoothed curves. This can be useful when you want to use a single source to modulate many parameters but don't want all the parameter transitions to have the same character.

Another possibility would be to patch a few of the outputs through quantizers and then to volt-per-octave oscillator inputs. As the input RUN voltage changes, each output will move through notes in the quantizer scales at different rates before arriving at the same final note. This can be useful for creating interesting, unexpected harmonies from within the same scale.

VOLLEY (cycle/shape): Modulation Bursts

VOLLEY converts JF into a triggerable envelope burst generator with control over the number of envelopes generated per trigger.

Typically in cycle/shape, the slope generators are freely running as LFOs. Triggers reset the LFOs to the start of their phase. In VOLLEY though, the slope generators are inactive by default. When a slope receives a trigger, a fixed number of cycles are completed (rather than an infinite number), creating a burst of modulation/envelopes rather than a freely-running LFO. Once the fixed number of cycles is completed, the slope generator becomes inactive again.

When CURVE is set fully CCW, VOLLEY becomes a gate burst generator and can be used for creating fills or quick bursts of notes.

  • As the RUN jack voltage increases, the number of cycles fired off will increase.
  • With the RUN voltage below -4V, the slope generators will be choked off and all incoming triggers will be ignored.
  • At -4V, 1 envelope will occur per trigger.
  • At 0V (or with a dummy RUN cable), 6 repetitions will occur per trigger.
  • At +5V, when a slope generator receives a trigger it will initiate 36 consecutive envelopes.

NB: The number of bursts is latched when the trigger input goes high, so you can sequence the burst count using CV sent to the RUN jack.

SPILL (transient/sound): Impulse-Trains, Subharmonics, and Sync Chaos!

SPILL combines cycle/sound and transient/sound to allow for impulse-train VCOs, chaotic subharmonics and sync sounds without an external oscillator - it gives you 6 MANGROVE-like oscillators without any patch cables! The behavior can become quite chaotic and textural, rather than tonal.

IDENTITY is a free running VCO as in standard cycle/sound. IDENTITY's end-of-cycle trigger pulse is used to excite each of the other receptive slopes, which are running as if they are in transient/sound: they rest at their minimum and wait for end-of-cycle triggers from IDENTITY to initiate an impulse. The RUN jack further extends transient/sound by adding the ability for the slopes to be retriggered while still active.

The RUN voltage is used to determine if an active slope is receptive to retriggering as in SHIFT: higher RUN voltages mean slopes do not become receptive to retriggering until later in their cycles. When active slopes are retriggered, they turn around from their current location, rather than resetting to the start of their phase.

INTONE CW: Impulse-Trains

With INTONE in the CW half of the knob's range, the 2N-6N slopes are shorter than IDENTITY. As such, they will always complete one cycle before IDENTITY does. The slopes then rest until IDENTITY excites them all again. The RUN voltage has no effect since all the slopes are already resting when IDENTITY reaches its end-of-cycle. Every slope retriggers every time IDENTITY sends its end-of-cycle pulse.

INTONE sets the timbre of outputs 2N-6N. INTONE works equivalently to MANGROVE's FORMANT control: it sets the speed of the slopes, while IDENTITY acts as the clock source. Turning INTONE CW from noon shifts the emphasis from the low-end to the high-end and adds harmonics as the pulse-width of each slope becomes narrower.

Typically in transient/sound, TIME acts like MANGROVE's FORMANT in constant formant mode, since it only controls impulse speed while an external oscillator controls the decoupled clocking rate. In SPILL though, TIME works like MANGROVE's PITCH control in constant wave mode: as IDENTITY clocks the impulse-trains at higher frequencies, the impulses become proportionally faster to preserve the harmonic structure. RAMP and CURVE provide additional levels of timbral sculpting unavailable on MANGROVE.

INTONE CCW: Subharmonics, Split-Tones and Sync Chaos!

When INTONE is in the CCW half of the knob's range, the 2N-6N slopes are longer than IDENTITY. They are all still active when IDENTITY sends its end-of-cycle trigger pulse. The RUN voltage determines which slopes will actually retrigger versus which slopes will continue their current cycle.

When RUN is set to +5V, the retrigger point is after each slope's end-of-cycle: in other words, they cannot be retriggered when they are active, only when they are at rest (equivalent to standard transient/sound behavior). Each slope will lock to different subharmonics depending on its index and the position of INTONE. The INTONE knob sets how much longer the 2N-6N slopes are in comparison to IDENTITY. This will determine how many cycles of IDENTITY complete before each other slope completes a single cycle and becomes receptive to retriggering. Each slope will only be excited once for every k cycles of IDENTITY, where k depends on the position of INTONE as well as the slope's index. The slope will be at the kth subharmonic (i.e. 1/k x IDENTITY's frequency).

As RUN decreases from +5V towards 0V, the retrigger point shifts from the end of the fall phase towards the start of the fall phase (aka end-of-rise). At 0V, the retrigger point is the start of the fall phase. Between 0V and +5V, all sorts of wildness can occur! This state is highly interactive between the RAMP, INTONE and RUN controls. Buzzy, rumbling split-tones can emerge, pitch divisions can happen, and all sorts of sync sounds in between!

As RUN decreases from 0V to -5V, the retrigger point shifts from end-of-rise towards the start of the cycle. AT -5V, the slopes are always retriggerable. Again, this state is highly interactive between the RAMP, INTONE and RUN controls. In addition to the previously described possibilities, glitchy, pulsing bursts of undertones enter and exit, creating unexpected rhythmic structures. With RAMP turned fully CW, more traditional sync sounds reminiscent of sawtooth-core oscillators become possible.

PLUME (sustain/sound): Lowpass-Gated VCOs and Polyphonic Synthesis

PLUME Block Diagram

PLUME implements the free-running oscillators of cycle/sound rather than the externally driven impulse-trains of sound/sustain; however, it passes these free-running VCOs through pluckable lowpass gates (LPGs) before reaching the final outputs and the MIX jack.

This mode is fantastic for polyphonic synthesis - all you need is a few trigger streams and you can immediately have beautiful overlapping polyphonic voicings - no external EGS, VCAs, LPGs or mixers necessary!

TRIGGERs will pluck the LPGs, but the trigger inputs are gate sensitive, allowing the LPGs to be held open for sustained notes. The TRIGGER inputs act like keys on a piano: holding a TRIGGER input high with a gate will sustain the corresponding note. Meanwhile, sending in short triggers will strike the notes, perfect for west-coast LPG plucks.

The RUN voltage controls the vactrol response curve:

  • With RUN at 0V, the LPGs respond similarly to the classic VTL5C3 vactrol with fast attack and moderate decay.
  • Positive RUN voltages shorten the attack and decay.
  • With negative RUN voltages, the TRIGGER inputs become more sensitive to the length of the input pulses as the attack and decay of LPG plucks lengthen. Shorter plucks will give softer notes.

Modulating RUN becomes an envelope time control and presents the ability to give different plucked notes different lengths.

With INTONE set fully CW, each TRIGGER input will pluck or hold a different note from a major triad chord (across a few octaves). Meanwhile, when INTONE is set fully CCW, each TRIGGER input will play a different note from a minor triad chord (across a few octaves).

Use the same gate source sent to a subset of the TRIGGER inputs to play chords.

If you have two JUST FRIENDS, configure one to be a trigger or gate delay in transient/sustain or sustain/shape and use it to strum the notes of the second JUST FRIENDS in PLUME (any other gate delay will work)! Or, try using multiple outputs from the first JUST FRIENDS in shape/cycle to strike various notes of the other JUST FRIENDS in PLUME; this will create a generative sequence that stays within a harmonic set of notes!

If you have a clock modulator which converts a single clock stream into multiple rhythm outputs (like a clock divider or pattern generator), try patching its various outputs to JUST FRIEND's inputs to create a sequence with overlapping notes whenever two of the rhythms go high simultaneously.

This mode can do more than just polyphonic synthesis though! It can be great for creating percussive sounds as well. Try patching an exponential envelope to INTONE in conjunction with plucking a TRIGGER - each output will have a varying amount of pitch sweep depth according to its index for varying levels of percussive-ness. Try self patching a few of the outputs to RAMP, CURVE, and FM. Now, in addition to the trigger which plucks your main slope, accent triggers can be sent simultaneously to the other TRIGGER inputs for different types of accents.

FLOOM (cycle/sound): 2-Operator FM VCOs and Noise Generator

FLOOM Block Diagram

FLOOM modifies cycle/sound by adding an internal FM oscillator and changing the functionality of the FM INPUT jack. Rather than patching an external oscillator to the FM INPUT jack, an internal sine wave oscillator is activated for each slope. The FM INPUT jack becomes a CV control for FM depth.

There is one internal sinewave modulator for each of the 6 outputs. The frequency of each modulator is directly linked to its corresponding output (carrier) oscillator. The output oscillator's frequency is determined by TIME & INTONE.

The RUN voltage determines the ratio of each modulator to its corresponding carrier. At -5V, the modulator is half the frequency of the carrier. Increasing the RUN voltage increases the ratio. At 0V, the modulator is the same frequency as the carrier. At +5V the modulator is double the frequency of the carrier.

The FM knob sets the depth of FM modulation by each internal modulator equally in the clockwise half, and proportionally to the output index (IDENTITY unaffected, 2N least affected, 6N most affected) in the counter-clockwise half. Positioning the knob in the CCW half can be useful for leaving the fundamental (IDENTITY) unaffected where traditional FM might thin out the low end.

The FM INPUT jack is no longer a frequency modulator input; instead, it becomes an FM depth input, allowing for CV over the depth of frequency modulation, in conjunction with the FM knob. Negative FM INPUT voltages invert the modulators before they are applied to the carrier, which can have dramatic effects when RAMP is away from noon.

FM bass lines can be immediately created without the need for an external modulator or a VCA to process the modulator. Try patching IDENTITY through a VCA and VCF for a standard subtractive voice. Use the same envelope to open both; additionally, patch the envelope to the FM INPUT. Use the RUN voltage to set the FM ratio and dial in your FM tone. Sequence IDENTITY with TIME, and you can have an instantly thick, heavy FM bass line!

Try patching an exponential envelope into INTONE or RUN in addition to the FM INPUT jack for more percussive hits from 2N-6N.

Patch a CV sequence into the FM INPUT to accent different notes in a rhythmic pattern with varying amounts of FM. Pair this with a separate sequence of a different length into RUN for an evolving set of FM timbres.

FLOOM RUN Voltage Ratio Sweep

FLOOM MIX Jack, FM Knob Sweep

Noise Generation in FLOOM

It is also possible to generate noise in FLOOM. Set RUN between -5V and 0V, and turn the FM knob to max, and set RAMP fully CCW or CW. The MIX jack will now be outputting broadband noise! CURVE, INTONE, and RAMP will adjust the character and color of the noise. The individual outputs will also be outputting noise, though the fundamental tone will come through a bit clearer. This can be useful for creating drum tones that change from pitched to noise!

FLOOM Noise Generation RAMP Sweep, MIX Jack

Firmware Update

How it works

The update procedure is done by playing a sound-file into the RUN jack of Just Friends. You'll need to use an audio playback device (like a computer or smart phone) to send the appropriate bits. With a special combination of settings, Just Friends will startup in bootloader mode and be waiting for you to upload the knowledge.

We use a modified version of Émilie Gillet's stm-audio-bootloader on Just Friends

Download

First you'll need to download the latest firmware. Make sure it's on the device you'll use for playback!

Get Connected

  1. Turn off your synthesizer.
  2. Set all knobs fully counter-clockwise
  3. Set switches to sound & cycle
  4. Connect a patch cable between the RUN jack & your playback device

Prepare your playback

  1. Set your sample-rate output to 48kHz (automatic on smart phones)
  2. Turn up the volume! 3/4 to maximum should do it
  3. Turn off notifications / sound effects (Do not disturb / Airplane mode is best)

Let's Go!

  1. Turn on your synthesizer
  2. 6N's light should be slowly pulsing
  3. Start playback of the audio file, IDENTITY will light, showing signal is being received
  4. 6N's light will move to 5N and dance with 4N for then next 90 seconds
  5. 3N will light temporarily and then Just Friends will restart anew!
  6. Disconnect the cable from your playback device first, then from the RUN jack!

All done!

Firmware Update Troubleshooting

Sometimes things just don't work out. Other times you can't take no for an answer. If the above instructions don't seem to be working correctly see if one of the below ideas might be your solution.

3N is lit as soon as you turn the synth on

This is probably a grounding issue. Connect / disconnect your playback sources power supply and then try again.

6N stays lit after audio starts

Sounds like the audio is either too loud, or too quiet.

If the IDENTITY light stays off, no signal is being understood by the module. Try increasing the volume on your playback device. If that doesn't work, check your patch cable is correctly connected, or perhaps turn off the synth & retry with a different cable.

If the IDENTITY light does come on, your audio is probably too loud. Just Friends is expecting a line-level signal, not a 10Vp-p Eurorack signal. If you're using a Eurorack preamp module for line-level signals, you'll need to turn the volume down below 1/4, maybe even less.

3N lights as soon as playback begins

This is likely a playback problem. Make sure your device is set to 48kHz playback sample rate. If you're using an audio DAW you probably have to do this in your DAW's settings. If the problem persists try a different playback device perhaps.

Update begins ok but then 3N lights solidly

The audio has likely been interrupted. Perhaps you received a text message & it's sound alert corrupted the stream? Turn on Airplane mode and try again. If it happens at the same point in the file, redownload the file - it might be corrupted!

Calibration and Factory Reset

You shouldn't need this, but just in case! Furthermore, if things go awry you can perform a 'factory reset' to return to the pretty-damn-accurate default settings (see below below).

Calibration Procedure

Calibration mode is launched at startup similarly to the bootloader, but with all knobs fully CW (maximum pots, sound, cycle, RUN jack inserted). Calibration settings are saved on-chip, so you'll only have to do this once.

  1. Turn off your synthesizer & set controls: all pots fully CW, sound, cycle, cable in RUN
  2. Turn on the power. You should only see IDENTITY lit, signaling calibration mode
  3. Connect your tuning voltage source to TIME. Set it to 0V output
  4. Switch to shape mode. 2N will light
  5. Set your voltage source to 2V
  6. Switch to sustain mode. 3N will light
  7. Switch back to cycle mode. 4N will light after a small delay while settings are saved
  8. Switch to sound mode. Just Friends will restart with your new settings.

Now each time you run JF it will use your custom calibrated values. Of course you can set different voltage offsets & tuning for truly weird behaviour. If JF is too fast, you could calibrate it to 1V & 3V to shift the pitch range down by an octave with no cable attached. Or calibrate to 2.4V for buchla standard 1.2V/octave. You probably just want to do it as outlined above though..

nb: The calibration settings will be retained even when re-flashing the firmware, so no need to re-do it each time you update.

nb: If you make a mistake with the switches in calibration mode it will just exit and use the existing setup. You can rerun the procedure as many times as you need.

Factory Reset

If you need to return to the factory tuning settings, follow the below steps:

  1. Turn off your synth & set the calibration mode settings (All knobs fully CW, sound, cycle, cable in RUN)
  2. Turn on & you'll be in calibration mode. IDENTITY will be lit
  3. Turn all knobs fully CCW
  4. Switch to shape. The module will pause for a brief moment while it overwrites the custom tuning, then restart as normal.

That's it!

Warranty

No matter if you just bought your first module, or found a grimey old relic, we're committed to keeping it running in top form.

Formally, Whimsical Raps warrants each product to be free of defects in materials or construction for a period of one year from the date of original purchase (proof of purchase required). Malfunction caused by abuse of the product, or any other cause that we determine to be the user's fault, will not be covered by this warranty.

Formalities aside, if you've got an issue we absolutely want to help sort it out. Send us an email and let us know how we can help. Our service fees are only our direct costs, and we typically ask you to pay shipping one-way. Here's to keeping synths out of landfill!

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