An experience of manufacturing and using of operator's hearing protection systems for strong acoustic noise environments

D. Babin, V.Dementienko, I. Mazourenko, A. Urantsev, A. Kholodenko
Tel. 939-45-04, 939-46-37, fax: 939-20-90
E-mail: dbabin@mech.math.msu.su
Address: Moscow, Vorobyovy Hills, Moscow State University,
Department of Mechanics and Mathematics, chair of Mathematical theory of Intellectual systems

For the hearing protection of the "Mir" station crew the headphones with active noise reduction were used.

Preliminary research of the Internet publications and the correspondence with the manufacturers has shown that the best variant for 1998 were the headphones for pilots by "PILOT AVIONICS" firm.

Our full acoustic tests of the complete headset have shown that the factors of noise reduction are the following:

The passive noise reduction is about 20dB in the range 500Hz – 10kHz and it has been archived with the aid of special form and materials with sound insulation properties. The active noise reduction is about 15-20dB in the range up to 500 Hz; it has been archived with the aid of generation of an "anti-noise" with the same frequency and opposite phase in headphones dynamics.

For a long operation aboard the "Mir" station the following principal modifications of the headset were required: manufacturing of the system charging device, which can operate with an onboard and 220V networks; adding of a microphone for communication sessions realization, and opportunity of listening of player; manufacturing the special chord for connection with onboard communication devices.

At the meeting after flight the station crew has noted, that use of such headphones is necessary, and so it recommended to improve the headset in the way, that will make it possible to put it on for a long time or even to sleep with it. For this purpose it is obviously possible to replace current headphones gaskets with gaskets, filled with a gel, and also to replace a current arch with an arch with smaller compression effort. Besides it is necessary to build an output to the station communication systems in the headphones. The activity in this direction is proceeding.