Is an Audiometric Test Booth Always Necessary? Rethinking the Quiet Room Standard

Professionals in hearing healthcare know that a quiet test environment is essential for conducting accurate, valid, and reliable hearing threshold tests. This is particularly important when the goal is to test hearing thresholds down to 0dB HL.

Traditionally, this has been achieved using a prefabricated isolated enclosure—commonly known as an Audiometric Test Booth (ATB). Most clinical audiology facilities and hearing aid dispensing practices rely on ATBs. Organizations such as ASHA, AAA, and ADA consider them best practice. (1,2,3)

However, the reality is there is an increasing demand for audiology and hearing healthcare services in remote and underserved areas—locations where the use of an ATB may not be practical, due to limited space, funding, or patient availability. (8) Providing these services is consistent with public health goals for increased access. (7) As a result, a reasonable question has emerged: Is an ATB always necessary for accurate hearing testing?

The Assumption: ATBs Guarantee Accuracy

It’s widely assumed that testing in an ATB yields the most accurate results. While this is generally true, the presence of a booth alone doesn’t guarantee accuracy. (6) Several factors can compromise the acoustic environment inside an ATB:

Factors That May Increase Ambient Noise Inside an ATB

• Installation environment: Noise from the surrounding area
• Booth construction: Single vs. double wall, wall thickness, and material quality
• Installation quality: Experience of installers and structural isolation
• Floor coupling: Isolation rails, neoprene mats, or direct contact with the building floor
• Component degradation: Poorly insulated jack panels, worn door seals
• Internal noise sources: Ventilation fans, electrical interference

While mitigation strategies exist, they are beyond the scope of this article. To that end, we strongly recommend discussing any potential issues with your ATB provider.

Understanding Acceptable Noise Levels

The American National Standards Institute (ANSI) (4) defines acceptable ambient noise levels in its standard S3.1-1999 (R2018). These Maximum Permissible Ambient Noise Levels (MPANLs) vary based on:

• Frequency (125 Hz to 8 kHz)
• Transducer type (insert earphones vs. supra-aural headphones)
• Ear coverage (both ears covered vs. uncovered)
• Test purpose (clinical vs. OSHA-related)

If ambient noise exceeds the MPANL at any frequency, the test’s accuracy at that frequency is compromised. For example, if the MPANL at 500 Hz is exceeded by 10 dB, an actual threshold of 0 dB HL may be recorded as 10 dB HL due to the masking effect of the ambient noise. MPANLs can be adjusted if hearing testing is to be conducted below or above 0dB HL.

Transducer Choice Matters

• Insert earphones and circumaural headphones offer the best ambient noise attenuation. (6)
• Supra-aural headphones are not recommended outside an ATB.
• Bone conduction and sound field testing require stricter control of ambient noise, especially at low frequencies (250–500 Hz).

ANSI’s Definition of an Audiometric Test Room

Interestingly, ANSI does not mandate a prefabricated booth. It defines an audiometric test room simply as:

“An enclosed space used for hearing testing.” (4)

This opens the door to boothless audiometry, provided MPANLs are not exceeded.

Determining the Need for an ATB

To decide whether an ATB is necessary, consider the following:

1. Analyze the Testing Environment

• Conduct an octave band analysis (250 Hz–8 kHz)
• Measure ambient noise on a typical day
• Determine if noise is steady or transient
• Assess how noise levels vary throughout the day

2. Define the Patient Population and Test Purpose

• Are you testing adults, children, or both?
• Will results guide medical or surgical treatment?
• Is testing used to confirm post-treatment improvements in hearing?
• Are there medical-legal implications?
• Will you conduct sound field testing for:
• Behavioral thresholds?
• Cochlear implant patients?
• Is the goal to determine hearing aid eligibility?

3. Consider Patient Experience

Ambient noise can distract patients, hindering their concentration and potentially the accuracy of the results. It may also undermine their trust in the test, the professionalism of the clinician, and the facility.

Boothless Audiometry: A Viable Alternative?

Provided a quiet test area is available, there are sound treatment and modern equipment technology solutions that can be implemented for boothless testing, such as:

Test Room Modification

• Add absorptive material to the room walls and ceiling
• Acoustical treatment of ventilation fans and ducts
• Reduce air flow velocity from ducts while maintaining a comfortable test space
• Seal areas around doors and windows to reduce acoustical leaks (6)

Real-Time Ambient Noise Monitoring

Audiometers like the GSI AMTAS Pro™ and GSI AMTAS Flex™ feature:

• Ambient noise monitoring microphones that measure ambient noise at octave frequencies in real-time and pause testing when MPANLs are exceeded
• Automated resumption once the ambient noise levels fall

Use of circumaural headphones to reduce ambient noise

• For air conduction testing
• Continued circumaural headphone use during forehead bone conduction testing to maintain attenuation referenced to “ears covered” MPANLs

When Is an Audiometric Test Booth Truly Necessary?

While ATBs remain the gold standard for hearing assessments, they are not always essential, feasible, or practical. However, there are specific scenarios where their use is vital to ensure the highest level of accuracy and clinical reliability.

ATBs Are Recommended When:

• Audiometric results contribute to medical diagnosis and treatment decisions
• Testing patients who may hear down to 0 dB HL
• Post-treatment evaluations to confirm improvements in hearing thresholds
• Pediatric behavioral testing using calibrated sound field speakers
• Cochlear implant (CI) candidacy evaluations and programming
• Speech-in-noise testing conducted via calibrated sound field speakers
• Ambient noise levels that cannot be adequately reduced by other means
• Conducting research

Final Thoughts

While ATBs provide optimal acoustic control and performance, boothless audiometry—when implemented with the right tools and environmental considerations—can be a practical and effective alternative. By evaluating the testing environment, patient population, and available technology, clinicians can make informed decisions about the most appropriate setup for accurate hearing assessments.

Have you determined a booth is necessary for your patient population and environment? Check out this blog from e3 to learn more about the sound booth installation process.

REFERENCES

1. Academy of Doctors of Audiology. (n.d.). Hearing Test Environment Guidelines. Retrieved from https://www.audiology.org/practice-resources/practice-guidelines-and-standards/
2. American Academy of Audiology. (n.d.). Practice Guidelines and Standards. Retrieved from American Academy of Audiology.
3. American Speech-Language-Hearing Association. (2005). Guidelines for Manual Pure-Tone Threshold Audiometry. Retrieved from American Speech-Language-Hearing Association.
4. ANSI/ASA S3.1-1999 (R2018). Maximum Permissible Ambient Noise Levels for Audiometric Test Rooms. American National Standards Institute.
5. Behar, A. (2020). Do we really need an audiometric test booth? Canadian Audiologist, 7(6). Retrieved from Canadian Audiologist.
6. Margolis, R. H., & Madsen, B. (2015). The Acoustic Test Environment for Hearing Testing. Journal of the American Academy of Audiology, 26(9), 784–791. https://doi.org/10.3766/jaaa.14072
7. Gates, K., Hecht, Q. A., Grantham, M. A. M., Fallon, A. J., & Martukovich, M. (2021). Hearing health care delivery outside the booth. Perspectives of the ASHA Special Interest Groups, 6(5). https://learningcenter.asha.org/diweb/catalog/item/id/8364370
8. Supply and demand resource list for audiologists. https://www.asha.org/SysSiteAssets/surveys/supply-demand-audiology.pdf

Dr. Lord is the National Clinical Trainer for e3 Diagnostics, a nationwide supplier of hearing and balance testing instruments providing consultative, sales, training, installation, calibration, and repair services. He also is an adjunct faculty member for the Osborne College of Audiology at Salus University (now Drexel University - Elkins Park Campus) in the residential and international bridge Au.D. programs. Dr. Lord earned his Master’s degree in audiology from Bloomsburg University and Au.D. from Salus University. His audiology areas of interest include electrophysiology, vestibular and balance assessment, and technical issues associated with instrumentation and calibration.