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 present technology. The edges of electrode hole were smoothened through after-etching processing to reduce air resistance, and the permeability of sound has been much more improved. Moreover, gold plating processing with large specific gravity further decreased the electrode vibration. Finally, the sound clarity has been achieved by reducing the resistance of electrode itself.

Intensity has been increased by giving roundness to the "guard mesh" of sound element, which lowered the influence of reflection and improved the resolution of sound.