A versatile looper for the Versio platform.
Repetita: from Latin Repetere for “repeat” (as in Repetita Iuvant, meaning “repeating does good”).
Versio: from Latin for “versatile”.
“Versatile repeater”
RV is a firmware that will require some time to master but will reward with a lot of fun even with just a few twists of the kobs. At its core it's two independent circular buffers for the left and right channels and its primary function is that of a looper, but its design lets RV go into other territories, such as delay, comb filter, stutter and distortion. It also can play nicely as a wavetable oscillator or provide various flavors of noise and raw percussions, even when nothing is connected to the inputs.
The features:
- 80 seconds stereo buffer @ 48KHz
- independent control for the left and right channels of loop start, loop length, speed, freeze amount and recording
- three trigger modes (triggered recording, free-running, one-shot) with input
- looper and delay mode
- variable decay with multi-mode filter and degradation in the feedback path
- loop start control with loop wrapping to maintain a fixed length
- loop length and playback direction in a single control
- reading speed control, from 0.02x to 4x, with controllable slew up to 10 seconds
- "note" mode with 4 octaves tracking
- instantaneous buffer freezing
- crossfading of frozen and unfrozen signals
- stereo width control
- feedback filter amount control
- input gain control
- settings are persisted between power cycles
This software is released under the MIT license, please see the LICENSE file included in the repo.
TL;DR: the firmware and the source code are provided as-is without any kind of warranty or support.
Download the latest version and flash your Versio with the online Programmer: https://electro-smith.github.io/Programmer/
Clone the repository with:
git clone --recurse-submodules https://github.com/hirnlego/repetita-versio
Inside the root directory you should find a subdir called wreath that is the module-agnostic looper engine. Inside it there are two Electrosmith packages, libDaisy and DaisySP that needs compiling by launching make from inside the respective directory.
Once done, everything should be ready.
I've used Microsoft Visual Studio Code as IDE and the project configuration is included in the repository. Also, a makefile is present.
To set up your development environment, learn how to debug with a probe and for general help with Daisy and the Electrosmith packages, please refer to their wiki.
The panel's labels depend on which Versio module you have, but using the Antri Versio nomenclature these are the controls:
- Knob 1 > [blend]
- Knob 2 > [start]
- Knob 3 > [tone]
- Knob 4 > [size]
- knob 5 > [decay]
- Knob 6 > [rate]
- Knob 7 > [freeze]
- ABC > [channel]
- XYZ > [button]
- FSU > [trigger]
Blend: Dry/wet balance control.
- ccw > fully dry;
- cw > fully wet.
Start: Sets the loop starting/re-triggering point. The loop wraps around at the end of the buffer, so its size doesn't change when the start point moves. It can be channel-dependant.
- ccw > begin of the buffer;
- cw > end of the buffer.
Tone: Applies a resonant filter to the feedback path. The default type is band-pass, but it can be changed to low-pass or high-pass in settings page (see below). When the looper is frozen some of this filtered signal is mixed with the wet signal that goes directly to the output. The resonance amount depends on the decay amount (the higher the decay the lower the resonance):
- ccw > cutoff at 0 Hz (no filter);
- cw > cutoff at 1500 Hz.
Size: Changes both the loop size and playback direction. It can be channel- dependant.
- ccw > full loop size but playback is reversed;
- noon > note mode;
- cw > full loop size, forward playback.
Decay: Controls the level of decay of the recorded signal. This signal passes through a degradation unit and a resonant filter. When the looper is frozen, this knob also controls how much of the filtered fed-back signal is mixed with the wet frozen signal.
- ccw > instant decay;
- cw > no decay.
Rate: The playback speed, from 0.02x to 4x. In note mode, controls the pitch in semitones (from -2 octaves to +2 octave). It can be channel-dependant.
- ccw > slowest rate (0.02x);
- noon > normal rate (1x);
- cw > fastest rate (4x).
Freeze: Progressively mixes the un-frozen and the frozen buffer. It can be channel-dependant. The signal that is normally written in the main buffer is also written in another identical buffer. When this parameter is greater than 0%, the second buffer is instantaneously frozen and is not written anymore. By turning the knob cw the wet signal is progressively mixed with the frozen signal, and when fully cw only the frozen signal is heard. To un-freeze the signal, turn the knob fully ccw at 0%.
- ccw > completely un-frozen (recording);
- cw > completely frozen (no recording).
Channel selector: The top switch set the channel currently controlled:
- left > left channel;
- center > both channels are controlled at the same time;
- right > right channel.
Trigger mode: The bottom switch sets different behaviors for the looper and how the button and the relative input work:
- left > the looper is continuously reproducing but the recording is stopped. One press of the button - or a positive voltage at the input - starts the recording, a second one stops it. The two channels can also be recorded separately using the channel selector;
- center > the looper is continuously recording and playing back its content. A press of the button, or a positive voltage at the input, restarts the reproduction at the position defined by the Start knob.
- right > the looper is continuously recording but the reproduction is stopped and can be triggered for a one-shot loop by pressing the button or with a positive voltage at the input. The reproduction always begins at the start position defined by the Start knob;
The advised startup state of the UI would be:
- Blend: 50%
- Start: 0%
- Filter: 0%
- Size: 100%
- Decay: 0%
- Rate: 50%
- Freeze: 0%
- Channel selector: center
- Trigger mode: center
As soon as the module starts, the buffer is filled with the input signal. During the buffering process the leds gradually light up red to represent how much buffer is being written, with all 4 leds fully lit representing a full buffer. The maximum buffer length is 80 seconds, but the process may be interrupted at any time by pressing the button, resulting in a shorter working buffer. Upon completion (or interruption) of the process, the reproduction of the buffer's content begins automatically. The buffer can be easily reset (see below).
When the bottom switch is either in the center or right position, the rapid press of the button restarts the reproduction at the start position (it can also be useful to re-synchronize the two channels when they've diverged). In one-shot mode (center position), it stops at the end of the loop. The same thing happens when a positive voltage is received at the relative input.
Global options can be accessed when the bottom switch is either in the center or in the right position by keeping the button pressed for more than 0.3 seconds. When in settings page the leds lit-up with either a light yellow, creamy color when in looper mode or a light blue, icy color when in delay mode. Caveat: because the Versio's CV inputs are tied to the respective knobs and it's impossible to establish if a parameter is being changed using either the knob or the CV input, voltages present at the inputs will affect the global options! Unfortunately the only workaround is disengaging the modulations before entering this mode. In this mode the knobs acts as follow:
Blend: Input gain (default: unity):
- ccw > 0 (no input);
- cw > 5x.
Start: Stereo width:
- ccw > mono;
- cw > stereo (default).
Tone: Filter type:
- ccw > low pass;
- noon > band pass (default);
- cw > high pass.
Size: Looper/delay mode:
- ccw > looper mode (default);
- cw > delay mode.
Decay: Filter level, that is the amount of the filtered part of the feedback that is written back in the buffer:
- ccw > 0;
- cw > unity.
Rate: Rate slew:
- ccw > 0 (no slew, default);
- cw > 10 seconds.
Freeze: Controls both the density and the amount of the degradation:
- ccw > no degradation;
- cw > maximum degradation.
The 4 leds visualize different information depending of the context.
During buffering, the leds light up gradually with a red color while the buffer fills. When the 4 leds are all lit with a bright red color the buffer has been completely filled. During the normal operation, the leds light up gradually indicating the read head's position of the longest of the two channels. Their color depends on both the current mode (looper/delay) and the Size knob's position.
In looper mode:
- cw > orange;
- flanger zone (forward) > yellow;
- flanger zone (backwards) > lime;
- ccw > green.
In delay mode:
- cw > blue;
- flanger zone (forward) > azure;
- flanger zone (backwards) > lavender;
- ccw > purple.
In both modes the leds are lit white(ish) when the Size knob is at noon.
In this mode the writing head uses all the available working buffer and its loop size never changes, resulting in every change made to the reading head to be written in the buffer. In this mode, then, the Size knob only acts on the reading head loop size, and changing it results in a stuttering effect, where the same fragment is continuously repeated and written in the buffer until the writing head finally loops and a new fragment is reproduced.
In this mode, activated by turning the Size knob clock-wise past noon while in the settings page, the reading and writing loop sizes are kept synchronized and the module acts as a delay, where the time is given by the loop size.
When the top switch is in the center (it should be the default setting), the Start, Size, Rate and Freeze knobs control both the left and the right channels at the same time. By flipping the switch either to the left or to the right, the channels may be controlled separately. When switching back to the center, the knobs now act as an offset, thus maintaining the distance between the left and the right position. To align the left and right channels again simply switch to each channel and twist back the knob to the current position, so the channel's value is updated.
Splitting the channels can produce a variety of interesting and complex effects, but there are two main caveats to be aware of:
-
it is sometimes impossible to realign the channels because twisting the knobs produce destructive modifications to both buffers, but dialing the same parameters for the two channels and re-triggering the looper might just do it.
-
more important and less obvious: for the same reason saw above when talking about the settings page, the modulation will always acts only on the currently selected channel, or on both at the same time if the switch is in the center position. This can be used creatively (for example as a randomization of sorts), but be advised that things can go out of control pretty fast :)
Note: when the left and right channels go out of phase, the separation can be very noticeable in the stereo field, even produce phase cancellation. To minimize the effect reduce the stereo width by turning the Start knob ccw while in settings page. This can also be useful for bringing closer two totally uncorrelated sound sources in the left and right channels.
The size of the working buffer is defined at the moment of the completion (or interruption) of the initial buffering process. In the case of requiring a buffer of different size, the buffering process can be repeated at any time. First, the operation must be armed by pressing and holding the button for more than 1 second. Once armed, the four leds will be all lit up red. Now pressing the button will start the buffering and a second press will stop it. Starting and stopping the buffering can also be done by sending positive voltages to the trigger input when the button mode is either one-shot or loop. Pressing and holding the button while armed will cancel the operation.
When the Size knob enters the flanger zone the Rate knob acts as a pitch control and the looper can function as a wavetable oscillator of sorts. If the Size knob is at noon the loop size is at its shortest (a little less than 1 ms) and the looper should produce a C4 note:
- Rate: fully ccw is 2 octaves below and fully cw is 2 octaves above. The relative CV input should track decently;
- Freeze: when fully frozen, the played sound fragment is fixed and thus the produced sound is clear and defined. Let some of the unfrozen sound pass through to get a more organic tone;
- Start: the timbre of the produced sound can be altered by changing the loop's starting point. If the sound's volume happens to be too low, try moving this knob to find a louder wave.
Jump-start the oscillation by placing the module in delay mode, Decay fully cw and Size at noon. From here, there's a lot of fun to be had by playing with the Size, Filter and Rate knobs. Don't forget to crank up the filter level (Decay knob in settings page) for a stronger effect!