Reduction of airflow noise in telephone handsets
Michael R. Stinson, Gilles A. Daigle, John F. Quaroni · The Journal of the Acoustical Society of America · 2004
The bursts of airflow that accompany plosive sounds such as a ‘‘p’’ or ‘‘t’’ can cause significant noise in a telephone handset when the talker’s mouth is close to the mouthpiece of the handset. Measurements of the generated noise have been made on a series of modified handsets, using various arrangements of ports and tubes between microphone and the mouthpiece exterior. The use of one, two and more exterior holes, and the introduction of different geometrical coupling between these holes and the interior microphone were explored. The noise could be reduced by over 20 dB by using an array of small (less than 0.5 mm diameter) exterior holes coupled with an offset to a sound tube leading to the microphone. [Work supported in part by Mitel Networks.]