JIS C 1509-1:2005

This Standard gives electroacoustical performance specifications for three kinds of sound measuring instruments: a conventional sound level meter that measures exponential time-weighted sound level; an integrating?averaging sound level meter that measures time-average sound level; and an integrating sound level meter that measures sound exposure level. A single instrument may make any, or all, of the three kinds of measurements. Additional performance specifications are given for the measurement of maximum time-weighted sound level and peak C sound level. Frequency-weighting A is mandatory for all sound level meters specified in this Standard. Sound level meters conforming to the requirements of this Standard have a specified frequency response for sound incident on the microphone from one principal direction in an acoustic free field or from random directions. Sound level meters specified in this Standard are intended to measure sounds generally in the range of human hearing. Two performance categories, class 1 and class 2, are specified in this Standard. In general, specifications for class 1 and class 2 sound level meters have the same design goals and differ mainly in the tolerance limits and the range of operational temperatures. Tolerance limits for class 2 specifications are greater than, or equal to, those for class 1 specifications. This Standard is applicable to a range of designs for sound level meters. A sound level meter may be a self-contained hand-held instrument with an attached microphone and a built-in display device. A sound level meter may be comprised of separate components in one or more enclosures and may be capable of displaying a variety of acoustical signal levels. Sound level meters may include extensive analogue or digital signal processing, separately or in combination, with multiple analogue and digital outputs. Sound level meters may include general-purpose computers, recorders, printers, and other devices that form a necessary part of

Reaffirmed 2014