A Medium-Sized Monitor Loudspeaker for Multichannel Audio Environments Conforming to ITU-R Recommendation

摘要

A medium-sized monitor loudspeaker is proposed and developed for multichannel audio environments conforming to the requirements of International Telecommunication Union Radiocommunication Sector (ITU-R): Recommendation (Rec.) ITU-R BS.1116-3. Moderate monitor loudspeakers are currently required in dubbing studios and experimental rooms in which multiple loudspeakers need to be installed. Such a loudspeaker requires a sufficient maximum sound pressure level, a flat frequency response, and an appropriate directivity providing a practical coverage; a size acceptable for multichannel audio environments is also essential. The proposed loudspeaker is developed realizing the directivity index within the specified target range by combining multiple loudspeaker units and controlling the cross-over frequencies. An integrally powered structure is adopted for convenience of installation, and a switching amplifier is selected for downsizing. As a result, the size of the developed loudspeaker gets suitable for the existing multichannel audio environments. The acoustic characteristics of the developed loudspeaker is investigated both in static and dynamic conditions. The measurement results verify that the developed loudspeaker conforms to almost all specifications of Rec. ITU-R BS.1116-3.