Sound Energy Integrator with an Electrostatic Squaring Device

Investigations of the contribution of short‐time delayed echoes to the intelligibility of speech have brought out the fact that reflections arriving within 95 msec after the direct sound in an auditorium have a positive contribution, and, reflections after this period, a negative contribution to the intelligibility of speech.

The instrument described, developed for the analysis of reflection patterns in auditoria, incorporates an electrostatic squaring device and an electronic counter as registration unit. Sound energy can be integrated by means of this instrument over pre determined short periods at any given interval after the direct sound.