An audiometer is a machine used by ENT (ear, nose and throat) clinics and audiology centers to measure hearing loss. Audiometers are typically part of the equipment used during an audiometry test. There are both software and hardware-based audiometers available in the market.

The hardware version is a simple machine that produces pure tones at controlled intensities. During hearing loss evaluations, the machine's output is heard by the subject in one ear at a time through a pair of headphones. The subject has a feedback button that enables them to respond when they hear the tone.

Audiometers may be standalone machines or can be integrated with a computer that controls it and offers a full suite of software tools and functionality. These devices come in many different types and use varying technologies. For example, some are bone-conduction systems while others are air-conduction based. It may be handheld, portable or a full-fledged machine intended for use in a single location.

The software-based device generates the same tone that is heard and responded to subjects in pretty much the same way. The only difference is that the tones in this case are prerecorded sounds stored in the computer. The audio output from the computer's sound card is sent to the headphones.

Hardware audiometers used by professional audiology centers, hospitals and research centers are more expensive, but also highly accurate and more reliable. These machines must be calibrated regularly to ensure that the intensity of the tone heard by subjects accurately reflects the level shown on the device display. Calibration also ensures standardized testing and consistent results no matter where the machine is used.

Audiometry software may be used as an alternative to a whole new machine. It will be cheaper and can be used by anyone at home and without assistance. However, calibration of the software is much more difficult and accuracy harder to obtain. People can still use it for regular testing, and only seek expert medical opinion if they discover any hearing loss.

The purpose of this arrangement, regardless of whether it is software or a physical device, is to pinpoint the exact audio level at which the subject stops responding. This allows the physician to diagnose the problem, if any, and provide treatment. Apart from actual ear cleaning to clear obstructions, the subject may also need to take ear drops. If the problem is more serious, a hearing-aid or surgery (or both) may be needed.

Another major application for audiometers is industrial audiometric testing. The actual process is pretty much the same as the one described above. One of the key differences is the fact that patients don't visit the clinic. Instead, a mobile lab with the required equipment and technicians comes to the industrial facility for testing the hearing levels of workers who are constantly exposed to noise.

The results are not only used to evaluate hearing loss, but also to decide whether the facility needs to implement noise muffling mechanisms. Such regular on-site checkups may also be required in group health plans in order to protect workers from any further loss in their hearing ability. An audiometer used in such applications must be extremely accurate, calibrated to within fractions of a decibel.