RGBmix is a custom project developed for Edutones, a team of music trainers based in Rotterdam. The project goal was to develop a simple audio mixer with a very accessible controlling interface for non-music people to be used in school-workshops with young students or in team building sessions for business teams.

Music Workshop, Wolfert College Rotterdam (The Netherlands)

Team Building Session, Rotterdam School of Management (The Netherlands)


The main characteristic of the RGBmix is the round-shape design. This specific clockwise placement of knobs and ports permit to 6 persons divided in 3 groups to sit around the table and cooperate on the mix and obtain an individual mixed output for each group.



The RGBmix hasn’t any label on the surface. The three colours: red, green and blue, represents the 3 different audio sources: a lead synthesiser, a drum-machine and a bass-synthesiser. So each coloured knob adjust the volume of the same color audio source. Headphones outputs and volume knobs are instead grey.


Concept Design

Schematic and PCB design

RGBmix is a portable rotary mixer with 3 stereo inputs shared between 3 independent mixing groups. This device it’s designed specifically for team-working and workshop activities.


  • 3 low-impedance stereo inputs (6,3mm jack)
  • 6 individual headphone amplified outputs with volume control
  • 3 mixing subgroups
  • Powered by a 9v battery or with DC jack 9v/12v
  • Power lights
  • Polarity protection circuit

The making of

The device is entirely 3D printed with FDM process and high quality shock-resistant PLA filaments.
The final result it’s a 15cm by 4cm hard shell without any visible screw. Some parts have been spray painted and sanded to reach the appearance we wanted to achieve.