Consumer-Grade Headphones for Children: Limited Effectiveness of "Level Limiters" When Used With Portable or Home Media Players.
Michael A Stone, Mark Harrison, Keith Wilbraham and 1 others
PMID 31868131WHAT IT FOUND
Children's headphones sold as volume limited could produce sound above 85 dB(A) with laptops or CD players.
Only one Bluetooth pairing showed a true limiter. Parents should not assume these labels make listening safe.
Key findings
01The LilGadgets headphone exceeded 85 dB(A), and laptop and CD player outputs were much higher.
02The Kidz Gear in-line limiter reduced output by a mean 11 dB across devices, entirely by a linear process.
03Only one instance of distortion-free hard limiting was observed, in the Puro Sound BT2200 via Bluetooth.
STILL TO COME
How it was doneWhat they found
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What it does not show
Only one sample of each headphone model was tested, so a single rogue unit cannot be ruled out. The study tested equipment in a lab, not children listening to real music or everyday programs. The signal used was program simulation noise and test tones, not a broad sample of music or streaming content. Volume controls were set to maximum, and equalization changes such as bass boost were not investigated. Bluetooth testing covered only two headphones. The paper reports no clinical outcomes, no participants and no therapist-delivered intervention.
Declared interests
The Hearing Device Research Centre at the Manchester Centre for Audiology and Deafness was commissioned by Firecrest Films to measure the headphones. The supplied text does not give a further conflict-of-interest declaration.
The easy way to misread this
Do not conclude that all children's headphones are unsafe or that these lab outputs prove injury. One sample per model was tested, and the study measured maximum output with test signals, not everyday listening.