Pianophonic is a polyphonic wavetable oscillator module for eurorack systems by Knobula.

Its wavetable engine is designed for emulating piano sounds but with control over a wide range of parameters allowing it to be adapted to various musical contexts.

We were responsible for firmware and hardware design of this device from concept phase to production as well as for the design of the wavetable format and the associated dsp code to generate sound banks.

The hardware is built around the daisy seed module. This imposed the challenge to maintain high quality sound output through separation between digital and analog signals in the face of the fixed pinout of the daisy seed and a large number of user interface elements.

Instead of using the daisy firmware SDK, we utilized our RTOS-based firmware framework consisting of UI handling, drivers and digital signal processing blocks. That allowed us to focus the development effort on a flexible and efficient sound engine that reaches the high throughput required for complex 32x polyphony and maintains the low latency required for a live instrument.

The device uses a custom wavetable format geared towards maximum efficiency during playback and ease of integration into firmware. A suite of software tools allows the creation of wavetable files from arbitrary recordings. Some parts of that suite are exposed in the online tool waveslicer.

This project is a multi-channel analog audio mixer with integrated preamp and voltage controlled panning.

We designed the circuitry and PCB for this product. The main focus was low noise requirements of the preamplifier as well as fine tuning the panning response curve. Routing was driven by the need to guarantee good input to output separation, minimal crosstalk and noise.

Idoru P-1 is a multi-channel audio and midi backing track player.

We were responsible for improving the existing firmware of the device in order to achieve better synchronization between audio and midi tracks as well as investigating future improvements on the hardware and firmware level.

This project is a complex filterbank with extensive user control capabilities. It features dozens of tuned bandpasses as well as complex vca circuits controlled from multiple sources.

The bandpass circuitry alone consists of more than 400 unique parts that had to be dimensioned and mapped to standard values for cost efficient manufacturing.

We made extensive use of circuit simulation to verify the frequency responses of all stages and identify sensitivities to component tolerances.

We undertook a project in collaboration with an established eurorack brand to develop an audio recording module for the eurorack format. The objective was to create a compact module capable of recording at least 5 channels of studio-quality audio to a standard SDHC card.

Managing large data rates reliably in the face of unpredictable delay caused by SD card write access times and filesystem operations required innovative buffering solutions.

Another challenge was fitting all necessary components into a small form factor without compromising the quality of the audio signal and while being restricted to lower density packages.

The project met all of its goals but unfortunately was terminated before turning into a product due to the global chip shortage.

We designed the circuitry containing among others an allpass network, a reference oscillator and a waveshaper. Due to our experience in this field we were able to deliver a manufacturable design in a short time frame.

Vibrations is a distributed robotic vibraphone by Moritz Simon Geist.

The installation consists of up to 36 tone plates connected to a central unit. Each tone plate is equipped with a mallet driven by a solenoid. A damper actuated by a stepper motor allows for sustained and non-sustained play modes. A piezo pickup senses the vibrations of the tone plate. Each plate is completed with electronics, digitizing the output signal of the piezo and controlling the mechanics.

For Communication the tone plates and the central units are connected in chains of up to 12 tone plates (heads) via regular ethernet cables. The four twisted pairs are used to exchange control data between the heads and the central unit, stream audio from the heads to the central unit as well as provide logic level power to the heads. The actuators on each tone plate are powered through a separate chaining system.

The central unit takes midi data for playing and configuring the instrument and provides analog audio outputs with mixed down signals from all connected heads.

We were responsible for hardware and firmware development. The central challenge of this project was the design of the high speed bus for streaming audio data between the heads and the central unit. We solved this with impedance controlled PCB design and by implementing a serial protocol synchronized by the central unit. The synchronization was also used to drive the resampling necessary due to the separated audio clock domains of heads and central unit.

Roseguarden is an open source access management system for shared spaces. It is developed at Konglomerat e.V. and currently in use to provide access to users of the fablab in #Rosenwerk.

The system consists of a self-hosted backend server and multiple door nodes connected to it via internet or local area network. Each door node physically controls the access to one door and allows users to identify themselves via RFID tags.

Our role in the project was to develop the firmware for a proof-of-concept door node on an ESP32 based platform.

Midilooper is a performative loop station that operates on MIDI messages. In contrast to looping in the audio domain where a lot of musical information has already been merged, this approach provides musicians with more flexibility to morph their loops. This way midilooper is crossing the gap between looping and sequencing.

For this device, we developed two special input circuits. One is a control voltage input that can be reconfigured through software into an interface for a passive pedal switch. The other one is a standard compliant MIDI TRS input that can also be used as a modular level clock input.

The firmware was developed completely by us. Its core feature is a storage structure for MIDI information that allows fast read and write access, arbitrary track lengths and flexible distribution of storage capacity between tracks. Additionally, it can be serialized to non-volatile memory allowing for fast and seamless switching between banks.

Thyme is an experimental delay-based effects processor.

As the instrument focuses on the exploration of the space inbetween classical delay based audio effects, we had to develop a signal processing chain that is both flexible to control and efficient in terms of processing power.

Next to firmware development, we supported hardware development and created a semi-automatic testing rig for production.

A quad hardware sequencer controlling synthesizers via CV/Gate and MIDI signals.

Being employed at KOMA Elektronik, Robert was responsible for firmware development. He was challenged by allowing near endless possibilities of CV-control while not compromising on timing precision.

To achieve a high precision voltage output without extending production times, he developed an automated calibration routine.

Toc-One a is toolbox for generating electro-acoustic music that we developed together with robotic music artist Sonic Robots. It consists of multiple beater heads that can be controlled through MIDI messages.

To be usable live on stage, the beaters needed to be relatively powerful while being connected to the central control unit only through long standard XLR microphone cables.

We contributed to the project in terms of circuit design and firmware development.

Strom is a series of modules for powering eurorack modular synthesizers.

The main goal of the development process was to design an affordable power solution while not compromising on safety measures and the quality of the provided output voltages.

Being a development engineer at KOMA Elektronik, Robert designed the circuits as well as the PCBs and built custom test equipment to aid the development process and help quality control in production.