Audio Media - September 2008 - (Page 56) AUDIO PRECISION APX525 Two Channel Analyser GRAHAM LANGLEY sets to work with the newest audio test and measurement kit from AP. he Audio Precision APx is the newest model in the APx Series of audio test sets. The range was launched with the APx and APx , eight- and -channel analysers, aimed specifically at power amplifier and CD/ DVD/MP player manufacturers, for use in R&D and production test. The APx is a two channel model available with both analogue and digital I/O, and there is a version without the digital I/O designated the APx . The system I/O can be expanded using a variety of switchers which need an additional computer USB port. Both are intended for use by a wide range of engineers who want to obtain fast and easy audio test measurement but do not need the ultra high performance of AP’s Series, or the multi-channel facilities of the APx / . Following in the steps of the ATS- , signals are generated and analysed in the digital domain using -bit/ kHz converters. Measurements can be analysed from DC to kHz. Signals can be generated internally, or for playback only devices, an external source can be used. AP provides a Resource disc which includes documentation, a full suite of test signals and a waveform creation tool. The basic measurements include level and gain, THD+N, frequency response, S/N ratio, crosstalk, interchannel phase, and CMRR. DC level, IMD, tone burst, and very high resolution FFT measurements are also available. All APx systems include a precision measuring instrument and the APx software, which runs on a PC. The connection to the host PC is made by a USB . cable. Data processing is carried out in the PC, therefore system performance is related to processor speed. The APx series are data intensive and AP recommends at least an Intel Core Duo or AMD Athlon X CPU with a minimum of GB of RAM for optimal performance. Both Windows Vista and XP are supported, but not in -bit versions. AP advises against running other applications concurrently. T First I mpressions The front panel has a clean and logical layout with modules for analogue output, analogue input and digital I/O, and a mains power switch. Analogue signals can be accessed by balanced XLR or banana connectors, and BNC connectors are provided for unbalanced signals. Digital I/O features AES , SPDIF/SMPTE, and optical Toslink connectors all with a sample rate of up to kHz. There are no user controls, all settings and measurements are made from the software interface. The rear panel provides connectors for power, USB computer interface, aux control in and out, and software options. The construction is to AP’s usual sturdy standards with a grey and blue finish. A U rack mounting kit is available and the optional carrying handle makes the . kg APx a portable test set in conjunction with a laptop. “The look is completely different from previous AP software with the intention of providing an intuitive user interface and improvement in testing time.” THE REVIEWER GRAHAM LANGLEY has been active in pro audio for 35 years. As co-founder of Amek and Total Audio Concepts, he designed many of their consoles. He now consults on audio projects. www. langley-design.com The look is completely different from previous AP software with the intention of providing an intuitive user interface and improvement in testing time. The first impression of the new GUI is the straightforward measurement-oriented layout. Most of the screen is occupied by a graph of the test selected, together with the necessary controls and a Start button to run the measurement. A tree structure Measurement Navigator is displayed in a window to the left of the screen. This allows the user to set up a Project containing signal path setup information, a series of customisable measurements, and to include user prompt and test limit information if required. This may be saved as a shareable file that contains control information only and can be run on any compatible APx system. It does not include any measurement results, reporting information or external programs called up by the prompts. Measurements carried out in R&D can therefore be replicated in manufacturing, or production tests can be carried out in any location. The Navigator > 56 AUDIO MEDIA SEPTEMBER 2008 http://langley-design.com
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