This part applies to sound system loudspeakers, treated entirely as passive elements. Loudspeakers with built-in amplifiers are excluded.
Note 1: The term “loudspeaker” used in this part relates to loudspeaker drive units themselves and also to loudspeaker systems, which comprise one or more loudspeaker drive units provided with a baffle, enclosure or horn and such relevant devices as built-in crossover filters, transformers and any other passive element.
The purpose of this part is to give the characteristics to be specified and the relevant methods of measurement for loudspeakers using sinusoidal or specified noise or impulsive signals.
Note 2: The methods of measurement given in this part have been chosen for their appropriateness to the characteristics.
Note 3: If equivalent results can be obtained using other methods of measurement, details of the methods used should be presented with the results.
Note 4: The following items are under consideration:
— loudspeakers with built-in amplifiers;
— measurements under conditions other than free-field, half-space free-field and diffuse field;
— measurements with signals other than sinusoidal or noise or impulsive signals.
2 Normative References
The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
GB/T 3241 Electroacoustics — Octave-band and Fractional-octave-band Filters (GB/T 3241-2010, IEC 61260-1995, MOD)
GB/T 3767 Acoustics — Determination of Sound Power Levels of Noise Sources Using Sound Pressure — Engineering Method in an Essentially Free Field over a Reflecting Plane (GB/T 3767-1996, eqv ISO 3744:1994)
GB/T 3769 Electroacoustics — Scales and Sizes for Plotting Frequency Characteristic and Polar Diagrams (GB/T 3769-2010, IEC 60263:1982, IDT)
GB/T 3785.1 Electroacoustics — Sound Level Meters — Part 1: Specifications (GB/T 3785.1-2010, IEC 61672-1:2002, IDT)
GB/T 6881.1 Acoustics — Determination of Sound Power Levels of Noise Sources Using Sound Pressure — Precision Methods for Reverberation Rooms (GB/T 6881.1-2002, ISO 3741:1999, IDT)
GB/T 6882 Acoustics — Determination of Sound Power Levels of Noise Sources Using Pressure — Precision Methods for Anechoic and Hemi-Anechoic Rooms (GB/T 6882-2008, ISO 3745:2003, IDT)
GB/T 12060.2-2011 Sound System Equipment — Part 2: Explanation of General Terms and Calculation Methods (IEC 60268-2:1987, IDT)
GB/T 12060.3-2011 Sound System Equipment — Part 3: Methods of Measurement on Audio Amplifiers (IEC 60268-3:2000, IDT)
GB/T 15212 Application of Connectors for Broadcast and Similar Sound System (GB/T 15212-1994, eqv IEC 60268-12:1987)
SJ/Z 9140.1 Sound System Equipment — Part 1: General (SJ/Z 9140.1-1987, idt IEC 268-1:1985)
IEC 60050(151) International Electrotechnical Vocabulary — Part 151: Electrical and Magnetic Devices
IEC 60268-14 Sound System Equipment — Part 14: Circular and Elliptical Loudspeakers — Outer Frame Diameters and Mounting Dimensions
IEC 60268-11:1987 Application of Connectors for the Interconnection of Sound System Components
3 Conditions for Measurement
3.1 General Conditions
This standard is to be used in conjunction with SJ/Z 9140.1, GB/T 12060.2-2011 and GB/T 6881.1.
3.2 Measuring Conditions
3.2.1 General
For convenience in specifying how loudspeakers are to be set up for measurement, normal measuring conditions are defined in this part. To obtain the correct conditions for measurement, some values (known as “rated conditions”) shall be taken from the manufacturer's specification. These values themselves are not subject to measurement but they constitute the basis for measuring the other characteristics.
