A short paper covering optics and music: the Uni-Vibe, which is responsible for the unique sound of Hendrix’
Woodstock performance, is one of many phasing devices based on photo conductive cells used as variable resistors.
However, its sound is well distinguishable from other phasers. In the paper we shall discuss the basic properties
and try to qualify and quantify the effect on the spectra of certain chords. The present paper is a side effect of
the musical interests of the authors and is triggered by the announcement of the Novel Systems Session including
the topics ’Optics and Music’ and Historical Devices.