2022 NHCA Annual Virtual Conference

Hearing loss is an increasingly serious problem not only for the elderly but also for the young.To achieve timely identification and management, many internet-based or smartphone-based test systems were proposed. However, conducting accurate audiometric tests outside sound booths introduces several challenges, such as ambient noise and stimuli level control, and mitigation of human errors. This study presents an approach to support multiple hearing tests in non-clinical settings with acceptable accuracy by using wireless earphones. Firstly, both earphones and over-the-ear earmuffs were used simultaneously, the ambient noise was reduced by the cushions of earphone and by the earmuff. Secondly, each earphone was calibrated during manufacturing to ensure design specifications such as frequency responses and tolerance ranges were met. The relationship between dBFS and dBSPL corresponding to a 2cc coupler measurement system was stored in the Bluetooth chip, and a protocol was developed for the host device to retrieve the conversion data from the earphone. Thirdly, the host device can accurately control the level of test stimuli played by the earphones through the Audio/Video Remote Control Profile. Results indicate that the output level error can be less than 1.5 dB, and maximum difference between different earphones was less than 2 dB.