MODEL RELEASED. Hearing test. A woman undergoing a hearing test stands in a soundproof room wearing headphones while a technician watches her through a window. The technician is using a machine called an audiometer to produce sounds of varying pitch and loudness in one ear at a time. The sounds de- crease in volume until they become inaudible. The patient responds each time she hears a sound by pressing a button. This type of hearing test, called pure-time audiometry, is used to assess the extent of a patient's hearing loss and to inves- tigate possible causes.