The sole output is either square or saw wave as selected by the waveform switch. The sole input is the (gated) control voltage which changes the pitch. The littleBits Oscillator module is a pretty simple affair. IN mode converts incoming MIDI note messages to two signals:Īlthough littleBits call the digital output “Trigger,” it really is a gate signal, as we shall see. OUT mode: Sends MIDI messages to the host.IN mode: Receives MIDI messages from the host.The mode is selected by its mode switch (duh!). However, the module operates in one mode (IN or OUT) at a time. The MIDI module supports both USB MIDI IN and USB MIDI OUT. The MIDI module has a USB-B device port that presents itself to the USB-A host as a class-compliant MIDI device. A close look at the MIDI module signals in action should tell us how littleBits implement basic synthesizer control (CV, gate and trigger). The first stage in the synthesis chain is the littleBits MIDI module.
I decided to start from the front of the synthesis signal chain and work back. My goal here is understanding the convention used by littleBits.
Maximum and minimum voltages level may differ by manufacturer and so on. On the other hand, old Yamaha and Korg synths use the Hertz per Volt convention. Moog, for example, use the linear Volts per octave convention. Not all mixtures are meaningful (useful), however.ĭetails about CV, gate and trigger vary from manufacturer to manufacturer.
#Little bits synth free#
Of course, electrons are electrons and one is free to combine CV, gate and tigger in any manner. Trigger signals often control synchronization. Trigger is intended to indicate an event, like a clock tick, not just the presence or absence of a condition. However, trigger is usually a short digital pulse. “ Trigger” is a digital signal similar to gate. The leading and trailing edge of the gate indicates a change in the condition. Gate indicates a condition, e.g., a key is pressed. A keyboard, for example, asserts gate when a key is pressed and drops gate when the key is released. CV sweeps continuously across an operational range, e.g., 0 to 5 Volts. “ Control voltage (CV)” is an analog signal which controls continuous functions like oscillator pitch generation, envelope and filter modulation, etc. Backgroundīefore diving in, here is a little background information about the signal types and terminology commonly used in modular synthesis.
Normalization facilitates the plug-and-play module architecture and you can freely interchange analog for digital and vice verse. Both digital and analog signals are normalized. littleBits modules normalize input and output signals to a 0 to 5 Volt range. We do know a few things about littleBits, however. Timing information, in particular, is needed. Precise information is needed especially when interfacing modules with the outside world including module synth gear. Not so good, neither Sphero nor littleBits provide precise documentation about synth module functionality or the input and output signal characteristics. Fortunately, they retained the littleBits forum. Since I last wrote about littleBits ( circa 2017), Sphero purchased the littleBits company in 2019. Folks hack the Korg Monotron series, so why not hack littleBits modules instead? The modules are inexpensive when compared with Monotron and are easily reconfigurable while experimenting. I got the itch to experiment with analog audio processing and finally unpacked the old littleBits synth modules.
0 kommentar(er)
