1. Pick-up System



First challenge was to construct a bridge for the acoustic bass that features the same characteristics as the one from the ZETA upright bass. Typical for this particular bridge, that was developed at Stanford University, and heavily patented was the material used: totally unusable  for a traditional double bass.

The first double bass bridge with 4 independent pick-ups was developed by Wilson:






1. MultiVoicer


MultiVoicer - is a music program for manipulating real time midi note data (but also as plug-in available in midiMorph). An incoming midi note generate a midi chord per midi channel. The incoming note can be the top note or the bass or the second voice.. of the created chord. The chord structure can be defined and mixed. Several permutation algorithms can be used. For jazzy improvisations there are ii-V and ii-V-I chord algo's. This works fine for walking bass lines but also Shearing like piano solo's. As an example listen to SpaceBass from MemBrain, the only player here is the Zeta midi uprite bass player. The chords are coming on the fly from multiVoicer and a Nord Modular synth.or listen to the piano part in DoLeSwing the start is a midiMorph pattern.

3. Digital Audio Workstation

Cakewalk Sonar Platinum is a software app used for producing, recording, mixing and editing audio like music, speech and sound effects.

Arturia Software (French) and Native Instruments (German) provide soft synths that I use in Cakewalk:



Seemingly a workable concept at first it turned out to be very complicated to even separate the four audio inputs after all. The fundamental reason for this system was to blend the four string as well as possible, rather than to separate them. The 4 strings could be individually fine tuned but would always interfere with each other.

In this link you can find some of my correspondence with Wilson.


The way the strings are separated in this model made it possible to send an audio signal to the interface from each of the 4 individual strings without any interference. This was not possible to generate from a double bass with a traditional wooden bridge.


2. RMC Poly Drive II


This device splits the signal into jack and a 13pin Midi Cable.




For technical information please see the attached PDF.

 For technical information please see the attached PDF.

2. MidiMorph


As an example you can listen to Music 1 made with module [gP] generate Patterns. This pattern music is in B flat. Another pattern is made with [gP] but now in D. Listen to Music 4. After generating these 5 (4/4) bars of music you can calculate musics in between. Listen to Music 2 (this is the morph 1/3 between music 1 and 4) and Music 3 ( morph 2/3 between music 1 and 4).

In the program you have several options for looping and morphing musics on the fly, but for now listen to the morph music going from B flat to D in Music 1-2-3-4 .

Listen to some MemBrain music. Most of the music is build on midiMorph patterns. Also in compositions midimorph can be used . Listen to the beginning of part 4 from SEQ called Ragtime 

 For technical information please see the attached PDF (in Dutch).

3. Interface

The Zeta Synthony II is a Midi interface originally made for the Zeta Upright Bass. See hardware 01. Not available anymore ; nevertheless, best one for Midi I have encountered.

For technical information please see the attached PDF.


4. Audio Interface


The RME UFX Fireface translates audio into digital information to be send to the computer.




 For technical information please see the attached PDF.                                                                                                                




5. Computer

In order to process the digital sound in a DAW (Digital audio workstation) and MultiVoicer software, it is important to use a laptop with a touchscreen. Live performance requires  a vivid interaction between player and hardware, A keyboard is more complex and sometimes difficult to see.



6. Midi Remote Controller


The Midi Remote Controller has four faders in order to balance the output signal from each string after the audio has been processed.


For technical information please see the attached PDF.


RMC PA-100X  Pick-up system

Consists of 4 piezo microphones 'on' and partly ‘ín’ the bridge.

Assembly is complex matter, that requires a luthiers craftmanship.