"Some time ago I had a job as a stage musician at a german opera house for a modern dance theatre piece. I had to play wireless because I had to move about on stage. My instrument had to sound in turn "classically", without any amplification, and on PA with a lot of overdrive and effects. I could not change instruments.
I could not use the piezo bridge I was accustomed to for 20 years, because the piezo is built into the G-string part of the bridge, which results in an audibly muted acoustic sound. With a clamp-on microphone the risk of feedbacks was too high.
Todays most pickup systems for string instruments are attached to the bridge, the soundpost or the body, which will always result in a muted instrument.
My idea of a solution was a magnetic pickup, which touches neither body nor bridge of my instrument. A one-piece, fingerboard-shaped pickup was the emergency measure in these days. Unfortunately with such an unflexible system the output of the strings is not balanced.
The shape of the bridge and the resulting position of the strings vary. With a one-piece, fingerboard-shaped electromagnetic pickup the position of the strings defines the distance to the magnetic coils and this way the amplified volume of the strings. With such a model the G-string has the lowest output, the other strings are gradually louder.
Every violinist, viola player, cellist or doublebass player who
amplifies his instrument, has an individual conception of its electric
sound. So an adjustible electromagnetic pickup is desirable. With the
REBO we have fulfilled this desire."