Sonometer /(?)/

So·nom·e·ter

Sonometer

n.
  1. An instrument for exhibiting the transverse vibrations of cords, and ascertaining the relations between musical notes. It consists of a cord stretched by weight along a box, and divided into different lengths at pleasure by a bridge, the place of which is determined by a scale on the face of the box. (Physiol.)
  2. An instrument for testing the hearing capacity.