TR-123e is a monophonic embedded bass synthesiser built on the Bela real-time audio platform: a Zero Delay Feedback four-pole Moog ladder architecture, translated from a Max/MSP gen~ patch into modular C++ running at approximately 1 ms latency on ARM, with an eight-parameter hardware control surface.

The design problem the project addresses is the loss that usually occurs when software synthesis is moved into hardware: the expressiveness and responsiveness of the patch rarely survive the translation. TR-123e treats the translation itself as the research object — a systematic port from gen~ to embedded DSP that preserves the sonic behaviour of the source while gaining the immediacy of a dedicated physical instrument. It is the built groundwork of a wider research practice in open instrument design, documented at cybernics.co.uk.

What this documentation covers

Signal path — oscillator, ZDF Moog ladder filter (zdf_moogladder_v2), amplitude and filter envelopes, and the audio callback structure.
Control architecture — MIDI event handling and timing, velocity parsing, key follow, and continuous pitch transitions via PortamentoFilter / PortamentoPlayer.
Class reference — every class is documented for legibility and modification; start from the Class List or the File List.

Source, hardware, and written study

Source code and schematics: github.com/gaialive/TR123e
Full written study — design rationale, comparative filter analysis, and the open-instrument argument: TR-123e_Dissertation.pdf
Surrounding research practice: cybernics.co.uk