Abstract
The accuracy of audiometric testing is fundamentally reliant on controlling ambient noise to prevent the masking of test stimuli. Various audiometric transducers, including supra-aural, circumaural, and insert earphones, as well as integrated headset systems, offer differing levels of passive sound attenuation. This white paper evaluates a range of commonly used audiometric headsets, determining their sound attenuation characteristics and calculating their specific Maximum Permissible Ambient Noise Levels (MPANLs) in accordance with ANSI S3.1-1999 (R2013) 1, or presenting published MPANLs where available. MPANLs are provided for testing to 0 dB HL. The objective is to identify transducers providing superior attenuation, thereby allowing for reliable audiometry in environments with higher ambient noise. A comprehensive table summarizes the 0 dB HL MPANLs for all evaluated headsets, highlighting the best-performing transducer at each standard audiometric frequency.
The Quiet Revolution
A Visual Guide to Audiometric Headset Performance in Noisy Environments
63.3
dB SPL
Peak Allowable Noise at 4000 Hz with the Top-Performing Headset
Why Attenuation is Critical for Accurate Hearing Tests
Accurate hearing tests demand a quiet environment. Any background noise can "mask" the quiet test tones, leading to incorrect results and flawed clinical decisions. While sound booths are the traditional solution, they are expensive and immobile. The alternative is using headsets that passively block, or "attenuate," ambient noise. The better the attenuation, the noisier the environment can be while still allowing for a valid hearing test. This infographic explores which headsets perform best, enabling reliable "boothless" audiometry.
Understanding the Standard: The MPANL Formula
Maximum Permissible Ambient Noise Level (MPANL) is the official measure of how loud a room can be for a valid test. The American National Standards Institute (ANSI) provides a baseline for a person with "ears not covered." A headset's performance is calculated by adding its specific sound attenuation value to this baseline. Better attenuation means a higher, more flexible MPANL.
ANSI Baseline MPANL
(Ears Not Covered)
Headset Attenuation
(Noise Reduction)
Final Headset MPANL
(Permissible Noise)
Head-to-Head: MPANL Comparison at 500 Hz
The 500 Hz frequency is critical for understanding speech. Below is a direct comparison of how much ambient noise different headsets can tolerate at this frequency while testing to a 0 dB HL threshold. Higher bars indicate superior performance and greater flexibility for testing outside a sound booth.
The Winner's Circle: Top Attenuation by Frequency
Different headsets excel at blocking different sound frequencies. Here are the top performers for each standard audiometric test frequency, showcasing the highest permissible ambient noise level (MPANL) achieved.
125 Hz
60.0
Kuduwave (Foam)
250 Hz
58.7
Kuduwave (Foam)
500 Hz
59.8
Kuduwave (Foam)
1000 Hz
53.8
Kuduwave (Foam)
2000 Hz
57.6
RadioEar DD65v2
4000 Hz
63.3
Kuduwave (Foam)
8000 Hz
59.8
Kuduwave (Foam)
Performance Profiles Across Frequencies
This radar chart compares the full performance profile of three distinct headset technologies. A larger shape indicates better overall attenuation across the board. Notice the significant advantage of integrated and insert systems over traditional supra-aural designs, especially at low frequencies.
The Attenuation Hierarchy
Not all headset types are created equal. The data reveals a clear hierarchy in noise-blocking capability. Integrated systems, which combine multiple layers of attenuation, and insert earphones, which seal the ear canal, offer the best performance for testing in non-ideal environments.
Integrated Systems (e.g., Kuduwave, WAHTS)
HIGHEST ATTENUATION
Insert Earphones (e.g., E-A-RTONE 3A)
Circumaural (e.g., DD65v2, HDA 200)
Supra-aural (e.g., TDH-39, DD45)
LOWEST ATTENUATION
Key Takeaways for Clinical Practice
Low Frequencies Matter
The biggest challenge for boothless audiometry is low-frequency noise (e.g., HVAC, traffic). Headsets with superior low-frequency attenuation, like the Kuduwave (Foam) and WAHTS, are the most reliable choices.
Fit is Everything
The data shows a vast difference in performance between foam and silicone eartips on the same device. A proper, deep seal with a foam tip is critical to maximizing attenuation and achieving valid results.
Choose the Right Tool
For testing outside a booth, standard supra-aural headphones are highly susceptible to noise. To ensure accuracy, clinicians must select transducers with documented high attenuation, such as integrated systems or insert earphones.