A UK engineer has come up with a solution to a problem that’s likely to cause conflict in homes across the country this Christmas.
When different generations of a family watch TV together and one or two people have hearing difficulties, the compromise is often a volume level that’s still too quiet for them, but annoyingly loud for everyone else.
Marcos Simón, a PhD researcher from the University of Southampton’s Institute of Sound and Vibration Research, hopes to bring peace to the nation’s living rooms using a highly-directional system of acoustical radiators commonly known as loudspeaker arrays. These produce a sound ‘hot spot’ by boosting the audio signal in one location while maintaining the same audio levels elsewhere.
The design, which comprises eight phase-shift sources in a line, aims to compensate for the hearing loss of a 70-year-old adult – about 15dB at 3kHz.
Simón, who won the Institute of Acoustics Young Person’s Award for Innovation in Acoustical Engineering for his array design, explained: “Although line arrays have been studied for many years, the approach previously used to reduce the radiation to the rear of the array – and hence reduce reverberant levels for other listeners – has been to position a second set of loudspeakers at the back of the array to cancel the sound in that direction.
“My array uses individual loudspeaker elements that are specially designed first-order acoustic radiators, or phase shift sources, thus saving cost and improving the robustness of the array to variations in the sensitivity of the elements and in the reproduction environment.
Experiments with a prototype in a test room show it’s possible to improve speech intelligibility for hearing-impaired listeners by almost a third while maintaining acceptable audio quality for others watching.