Planning ANC Headphone Laboratories: Noise Reproduction, Fitting and Measurement Space
An R&D laboratory for noise-cancelling headphones needs to reproduce external noise consistently and compare headphone performance in different cancellation states. Plan the measurement space, noise-reproduction system, fitting fixture and operating procedure together before selecting the room type and equipment.
This article addresses development of consumer active noise-cancelling headphones. It does not address conformity assessment of hearing-protection equipment.
Define the tasks for the first phase
Music reproduction, attenuation of external noise and microphone performance during calls are different test tasks. A project brief can include all of them, but it should identify the method and required output for each. Otherwise, a “headphone test system” becomes an undefined package of functions.
IEC 60268-24:2023 specifically addresses active acoustic noise-cancelling characteristics, including measurement and evaluation methods. It excludes equipment intended for hearing protection.[1] If cancellation development is the immediate priority, define that capability explicitly rather than assuming that communications or hearing-protection tests are also covered.
Include noise reproduction in the room layout
External noise is a controlled test input in cancellation measurements. Listen’s public application guide illustrates loudspeaker-generated noise and measurements with no headphones fitted, headphones fitted with ANC off, and ANC on.[2]
Alongside the room quotation, specify how noise will be generated, where it will be checked and how the different states will remain comparable. A proposed layout should show the loudspeakers, test head or fixture, checking positions and access routes. The selected test method should determine the sound field, loudspeaker arrangement and calibration procedure. A demonstration setup is not a substitute for the formal method.
When reusing an anechoic room, first verify whether the room and reproduction system together can support the intended task. The room’s name alone does not establish that the required cancellation-test conditions are available.
Allow space for fitting and sample changes
How headphones are fitted to the test device can affect the measurement. GRAS explains that pinna shape, compliance and sealing influence fit and measurement repeatability.[3] Select a fixture suitable for the headphone design rather than checking only whether the equipment list contains an “artificial ear.”
Provide organized storage for ear tips, cushions and samples, with convenient access for fitting, inspection and refitting. Development comparisons should record the fitting procedure, accessories, firmware and cancellation mode. When fit-to-fit variation is part of the investigation, define the number of refits and treatment of results in the test plan instead of retaining only one response curve.
Connect quotations and handover to the same tasks
Ask each proposal to explain four deliverables:
- Room conditions: supported methods, frequency ranges and operating states requiring verification.
- Reproduction and measurement system: sound sources, fixtures, connections and configuration boundaries.
- Operating procedure: sample changes, state checks, comparisons and record keeping.
- Verification tasks: representative samples that demonstrate operation of the agreed configuration and procedure.
After installation, verify the agreed room specifications and run a complete procurement-defined workflow. Check that noise reproduction, fitting, state changes and result storage work together. The contract should distinguish responsibilities for the room, measurement equipment and test method. Detailed standard clauses and decision criteria still need to be checked against the formal documents.
This approach keeps proposal comparisons focused on the development team’s needs: whether the laboratory supports consistent, reviewable cancellation comparisons, and what would be required to add further tasks.
References
[1] IEC, IEC 60268-24:2023, public scope: Sound system equipment — Part 24: Headphones and earphones — Active acoustic noise cancelling characteristics.
https://webstore.iec.ch/en/publication/67683
[2] Listen, Inc., Headphone Active Noise Cancellation (ANC) Measurement, public application guide. Its configurations are examples, not substitutes for standard requirements.
https://www.listeninc.com/applications/headphones-headsets/headphone-active-noise-cancellation/
[3] GRAS, Acoustics FAQ, technical discussion of headphone fit, pinnae and measurement repeatability.
https://www.grasacoustics.com/faq
