Version 4.6 APx500 Measurement Software Now Available

New capabilities include open-loop chirp, multichannel input equalization and DTS:X support

BEAVERTON, OREGON, September 18, 2018: Audio Precision announced today the availability of APx audio measurement software version 4.6. With this release, AP has added the ability to perform measurements using the logarithmically-swept sine (i.e., “chirp”) in an open-loop configuration, multichannel input equalization, DTS:X support and the automated import of measurement equalization curves.

Open-Loop Chirp

With an enhancement that will be of interest to those developing smart devices (e.g., smart speakers, smartphones), APx release 4.6 enables open-loop measurements using the chirp test signal. This signal provides multiple, high-resolution results in a brief period of time and now APx users can employ the chirp in test scenarios where the signal may originate, or terminate, as a file on the device under test (DUT) or on a server connected to the DUT.

Multichannel Input Equalization

APx release 4.6 also adds the ability to simultaneously correct for multiple microphones. From left and right ear simulators in headphone testing to a sixteen-microphone array being used for car tuning, APx audio measurement software now provides real-time filter-based correction of all input signals.

Additional Capabilities

Version 4.6 also adds support for DTS:X™, enabling the playback and capture of pre-encoded DTS:X bitstreams by developers working to meet DTS compliance test requirements. For Bluetooth® Duo equipped APx analyzers, AAC MPEG-2 codec support is now enabled. Finally, input EQ curves can now be imported as part of an APx automated test sequence.

Release version 4.6 will not operate (except in demo mode) without an APx KeyBox installed on the user’s APx audio analyzer. For additional information on the APx KeyBox, including how to request one free-of-charge, users should visit The release is available for download by registered users of and is compatible with all analyzers in the APx500 Series. Use of the open-loop chirp capability with APx515 analyzers requires at least one software option or bundle that contain a supported chirp measurement.

Site Links:

APx Audio Measurement Software (must be logged in to download)

APx KeyBox Information

APx KeyBox Request Form

About Audio Precision

Audio Precision (AP) is a recognized world leader in electronic audio and electro-acoustic test instrumentation. Since 1984, AP’s analyzers have helped engineers to design and manufacture innovative solutions ranging from semiconductor devices to consumer, automotive, and professional audio products. For more information, visit

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