Overview
IEC 62585:2012 is an International Standard developed by the International Electrotechnical Commission (IEC) that focuses on electroacoustics, specifically methods to determine corrections needed to obtain the free-field response of a sound level meter. This standard provides comprehensive guidance on the necessary frequency-dependent corrections that enable precise periodic testing of sound level meters as per IEC 61672-3. Its primary goal is to establish consistent and reliable approaches for calibrating sound level meters to ensure their measurement accuracy, especially regarding sound reflections, microphone response deviations, and accessories like windscreens.
Key Topics
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Correction for Sound Reflections and Diffraction
IEC 62585 details the methods to account for typical effects caused by reflections from the sound level meter's case and diffraction of sound waves around its microphone. These corrections are crucial to ensure that the sound level meter accurately measures sound as if in a free-field environment (no reflective surfaces nearby).
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Microphone Frequency Response Deviations
The standard addresses adjustments needed due to the microphone’s deviation from an ideal uniform frequency response when direct measurement of the actual microphone response is not feasible. This ensures that the sound level meter readings are corrected to represent true sound pressure levels across frequencies.
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Accessory Impact Corrections
The influence of accessories such as windscreens and other attachments that are part of the normal meter configuration on the frequency response of microphones is also covered. Correcting for these attachments ensures accurate measurements in typical real-world applications.
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Uncertainty of Measurement
IEC 62585 discusses uncertainty factors associated with correction measurements and specifies maximum permitted expanded uncertainties for manufacturers and testing laboratories. This supports conformity assessment and helps maintain high standards during calibration and periodic testing.
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Adjustment Values at Calibration Check Frequencies
The standard defines the methodology for determining the adjustment value manufacturers should quote at the calibration check frequency, optimizing the meter’s performance over its operating frequency range.
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Measurement Methods with Various Calibration Tools
The document specifies procedures for determining frequency corrections when using recommended instruments such as sound calibrators, comparison couplers, or electrostatic actuators to ensure the free-field equivalent sound level is obtained during testing.
Applications
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Sound Level Meter Manufacturing
Manufacturers utilize IEC 62585 to establish correction values and adjustment factors necessary for their sound level meters to comply with IEC 61672 series standards. This supports product reliability and international market acceptance.
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Calibration and Testing Laboratories
Testing facilities apply the methods specified in IEC 62585 when performing periodic pattern evaluations and testing of sound level meters. Adherence to this standard ensures traceable and consistent measurement results and helps laboratories meet accreditation requirements.
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Environmental Noise Assessment
Accurate sound level meter calibration following IEC 62585 guidelines is vital for environmental noise monitoring, ensuring that measurements reflect true environmental sound levels free from equipment-induced anomalies.
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Occupational Health and Safety Compliance
Organizations monitoring workplace noise risks benefit from sound level meters calibrated in accordance with IEC 62585, supporting compliance with safety regulations and protecting workers from hazardous noise exposure.
Related Standards
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IEC 61672-1:2002 - Electroacoustics - Sound level meters - Part 1: Specification
Defines performance requirements for sound level meters which IEC 62585 supports by providing methods for correction and calibration.
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IEC 61672-3:2013 - Electroacoustics - Sound level meters - Part 3: Periodic tests
Specifies periodic testing procedures where the corrections and adjustment methods in IEC 62585 are applied.
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IEC 60942:2003 - Electroacoustics - Sound calibrators
Governs sound calibrators used during calibration and measurement procedures referenced in IEC 62585.
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ISO/IEC Guide 98-3:2008 - Uncertainty of measurement - Part 3: Guide to the expression of uncertainty in measurement (GUM)
Provides the framework for uncertainty assessment relevant to measurement corrections discussed in IEC 62585.
Adherence to IEC 62585:2012 ensures that sound level meters provide accurate, reliable, and consistent measurements by accounting for environmental and equipment influences through standardized correction methods. This facilitates international consistency, regulatory compliance, and trustworthy acoustic measurement results in diverse applications.
Open preview (PDF)Electroacoustics - Methods to determine corrections to obtain the free-field response of a sound level meter
