A Chronographic Method of Measuring Reverberation Time

A description is given of apparatus which measures the rate of decay of sound density in a room. A loud speaker, energized from an oscillator, is preferably used as the source of sound. Current is sent through the speaker until the sound in the room has reached a steady state, whereupon the speaker is disconnected from the oscillator and the time required for the energy density in the room to decay to a definite value is recorded by the apparatus.