Audio Precision Takes the Headache Out of Earphone Testing

Created on 2010-08-09 06:00:00

New utility for APx audio analyzers saves engineers time with automated BS EN 50332 testing


Beaverton,Oregon, Aug 9, 2010:Audio Precision, the recognized standard in audio test and measurement, hastoday produced a software utility that automates testing of headphones andearphones used with portable audio players. The utility, which runs exclusivelyon Audio Precision’s APx Series analyzers, automates the measurements requiredby British Standard / European Norm 50332 Parts 1 and 2.

Theaccompanying new AP Technote “Measuring the Sound Pressure Level of PortableAudio Player Headphones with APx Audio Analyzers” describes in detail how to use the utility to conduct the tests specifiedin the standard.

Accordingto Audio Precision distributor Man Li of AP Technology in China, the newutility and its accompanying Technote will save manufacturers hundreds of hoursof development time and “reduce the possibility of costly mistakes in theirtesting programs.”

Thestandard requires a special Program Simulation Noise test signal and a testfixture known as a Head and Torso Simulator (HATS). Sound pressure levelsmeasured in the ear simulators of the HATS must be corrected to free fieldresponse and then A-weighted and averaged.

 “The calculations needed to derive the resultsrequired by the standard are too complex for the typical user to do manually”,says Joe Begin, head of AP’s Technical Support. “And the Program Simulation Noise signal would also be a challenge forcustomers. We used Matlab™ to create the signal in the digital domain. Theutility bundles that in and takes care of all the necessary calculations.”

Theautomated software utility was written for users of APx Series audioanalyzers. APx is a next-generation platform with several models includingthe high performance APx525, the multichannel APx585 and the low cost APx515optimized for production test. All APx models use the same software and featureone-click automation, award-winning UI, and automated reporting. Each APx analyzercomes with an ISO:17025 Accredited Calibration and three year warranty, soresults are trusted everywhere.

TheTechnote can be downloaded at no charge from AP’s website

Forthis Technote, AP used a KEMAR Manikin Type 45BA Head and TorsoSimulator provided courtesy of G.R.A.S. Sound and Vibration.


AboutBS EN 50332

TheBritish Standard / European Norm (BS EN) 50332 standard is intended to protectusers of portable audio devices from exposure to excessive sound levels, andhas been adopted by the 31 European CENELEC (European Committee forElectrotechnical Standardization) member countries.


AboutAudio Precision

AudioPrecision is the recognized standard in audio test and measurement, with abroad portfolio of high performance audio analyzers designed to provide theright instrument for any audio test, including super low distortion, ultra highbandwidth, multichannel, HDMI or fast production test. Since 1984, AP hasoffered high performance audio analyzer instruments and applications to helpengineers worldwide design and manufacture all types of consumer, professionaland industrial audio products. For more information, visit

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