Disclosed is audiometer apparatus including a tone generator portion, attenuator network, accoustical transducer and two-dimensional plotting mechanism for automatically recording the subject's response to signals received at the transducer. The tone generator includes a plurality of continuous running oscillators whose discrete frequency signals are coupled through pulser circuitry to the attenuator by way of magnetic reed switches actuated by the movement of the plotter. Hearing loss information is plotted with a pair of different color ink pens disposed within a carriage on the plotting mechanism. Switching mechanisms control the movement of the plotter and the carriage in their respective directions, selectively move the pens into and out of contact with recording material, and switch the signals received by the transducer from one earpiece to the other. Random validity mechanism is incorporated with apparatus for periodically or manually inserting an additional intensity change to the generated tones. Pulser circuitry, utilizing a photoresistor, is adapted for periodic interruption of the generated signal, the rise and decay characteristics of the generated signal being controlled by the circuitry.
AUDIOMETER APPARATUS