標準號：IS 9551 Pt.3-1979
發布日期：1980/12/1 12:00:00
實施日期：1999/12/31 12:00:00
適用范圍：1.1 This standard ( Part III ) specifies the performance requirements for loudspeakers to be used in high-fidelity audio equipment and systems.1.1.1 This standard applies to loudspeakers and loudspeaker systems, which are provided with a sound conduction device (for example, acoustical enclosure).1.1.2 It also applies to loudspeakers and loudspeaker systems without such a device. In such cases, the suitable sound conduction device, for which they are intended, shall be described fully and cleaily and together with this device the performance requirements have to be fulfilled.Note — The principle of sound excitation, the kind of conduction and the set-up and number of built-in loudspeakers are optional.