STAX SR-009S (Demo)Sound element with new fixed electrodes If the fixed electrode becomes infinitely thinner, the air resistance will be decreased and the permeability of sound waves will be improved. On the other hand, thinner electrodes are poor in rigidity and suffer from vibrations of their own and the sound becomes muddy. The SR 009S evolved further the electrode established in the SR 009 as the integration of presenttechnology. The edges of electrode hole were