According to the National Institute of Health (NIH), approximately 15% of American adults (37.5 million) aged 18 and over report some trouble hearing, about one in three people in the U.S. between the ages of 65 and 74 has hearing loss, and nearly half of Americans aged 75 and older have difficulty hearing. Audiometry tests therefore show that it is extremely common to lose our hearing as we get older. ASA/ANSI S3.6-2025: Specification For Audiometers provides specifies performance and calibration requirements for audiometers, which are devices used to measure hearing thresholds.
What Is An Audiometer?
An audiometer is an electrical medical device used to test hearing acuity in humans. It measures a person’s ability to hear different sounds, pitches, or frequencies. Audiometers can be used for several different types of hearing tests. They are classified as a medical diagnostic device under the ear, nose, and throat category. Its parts include a sound generator, oscillator, attenuator, microphone, and earphone.
What Is New in the 2025 Revision of ASA/ANSI S3.6?
The new 2025 edition of ASA/ANSI S3.6, Specification of Audiometers, defines updated performance and calibration requirements for audiometers. The ASA/ANSI S3.6-2025 revision introduces no new technical changes, as this standard was reaffirmed, not revised, in 2025. The affirmation confirms the standard’s current relevance and accuracy, assuring it remains a foundational resource for the specification of audiometers by supporting reliability and consistency in worldwide hearing measurements.
It specifies that changes in the standard are not intended to be retroactive to audiometers manufactured and calibrated in accordance with an earlier version of the standard, and that the version of the standard prevailing at the time of manufacturing and calibration should be stated.
What Is ASA/ANSI S3.6-2025?
ASA/ANSI S3.6-2025 specifies requirements for audiometers used primarily to determine hearing threshold levels with respect to standard reference threshold levels as well as instruments used primarily for audiometric
testing purposes which incorporate calibrated sound sources (e.g., acoustic immittance systems,
otoacoustic emission systems, or narrowband noise generators).
The requirements in this American National Standard cover the general specifications for audiometers that require behavioral responses from a listener, including requirements for the functions units of audiometric equipment such as type of signal, signal level control mechanisms, and types of transducers.
Audiometer Types and Classifications in ASA/ANSI S3.6-2025
Audiometers in ASA/ANSI S3.6-2025 are classified according to the type of signal generated (pure tones, speech, or both), mode of operation, and complexity or range of auditory functions tested. Audiometers are also classified by type and class.
Audiometers used for pure-tone diagnostic assessment are classified as Type 1, 2, or 3, while audiometers having only air-conduction capability are classified as Type 4. Audiometers used for speech assessment are classified as class A or B according to the complexity of the instrument’s capability.
What Are the Types of Audiometry?
There are many types of audiometry tests. Here are some of the more common tests:
Pure Tone Audiometry
This test involves wearing a set of headphones connected to an audiometer. As you wear the headphones, pure tones are sent to your ears and each ear gets tested individually. The tones vary in frequency/pitch and are measured in hertz (Hz), and intensity/loudness are measured in decibels (dB). During the test, the patient is instructed to raise their hand, press a button, or signal when they hear a tone. The results of the test are placed on a graph—an audiogram—along with the minimum thresholds for normal hearing levels. This is known as an audiogram and is used to graphically represent hearing loss on a defined scale.
Bone Conduction Audiometry
An audiometer can determine how well the cochlea (i.e., the spiral activity of the inner ear) functions. A device called a bone oscillator is placed on the forehead or behind the ear, usually as a headband and sounds are sent through the oscillator, causing the bones in the skull to vibrate. This bypasses the middle and outer ear to directly stimulate the cochlea. Both air and bone conduction testing are done to determine if someone has conductive hearing loss or sensorineural hearing loss.
Speech Audiometry
Speech audiometry tests how well you can hear, understand, and repeat speech. You will wear a headset through which words are spoken at different volumes. This is measured as the speech reception threshold (SRT), which is the lowest level in dB that you can repeat half of the words correctly. In addition, you are assigned a word recognition score (WRS), the number of correctly repeated words out of the number of presented words.
How Can You Tell If You Have Hearing Loss From an Audiogram?
An audiogram is used to graphically represent hearing loss on a defined scale and it measures hearing ability and the degree of hearing loss. Simply put, it is a graph that shows the softest sounds you can hear at different frequencies and pitches. For reference, a face-to-face conversation is about 65 decibels (dB); sounds louder than 85 dB that you may hear at a live concert can cause hearing loss after only a few hours. The results of an audiometry test are an indication for the degrees of hearing loss:
- Normal hearing: -10 to 20 dB
- Mild hearing loss: 20 to 40 dB higher than normal
- Moderate hearing loss: 40 to 70 dB higher than normal
- Severe hearing loss: 70 to 90 dB higher than normal
- Profound loss: 90 dB or more
ASA/ANSI S3.6-2025: Specification For Audiometers is available on the ANSI Webstore.
ASA/ANSI S3.6-2025 is developed by the Acoustical Society of America (ASA).
Please direct any technical questions relating to this American National Standard to the developer. You can find the contact information for all standard developing organizations (SDOs) here: Who to Contact for Standards Related Questions.