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Audio Precision APx Audio Analyzers

In short, the APx measurement software is fast, effective, and full-featured.

In general, sophisticated test instruments once had a single main function per device until the development of computer- driven, multi-function test gear. Graphically, the somewhat utilitarian GUI interfaces for devices like Audio Precision’s System One/Two/2500/2700 test sets were designed for functionality, control and operator feedback — enormous configurability with the potential for a cluttered appearance. As geeks, control and information were the goals of those of us using such devices.

A potentially cluttered screen was certainly not more of an issue than having five or six different hardware test instruments all stacked up, each with their own displays and controls and operating schemes. The software interface for the APx500 series brings a significant change in operational paradigm. Now, a moderately technically inclined individual can perform a sophisticated panel of tests with a few mouse clicks. In practice, for comparative bench testing and manufacturing quality control, the APx approach is very practical and elegant.

For the novice, the steps necessary to customize a test for a particular device are simple — the user is walked through the steps necessary to establish deviceto- test set connections, test elements and parameters settings — straight-forward and elegant. The onscreen interface is visually appealing and uncluttered, showing just what you might need to see at a given point in time and including aesthetically pleasing elements like interconnection illustrations and graphical knobs. Reports produced (and saved as pdfs) giving the results of a test sequence offer quick pass/fail assessment as well as sweep plots and a log of test configuration and test data. Test elements can be added or subtracted quickly with a mouse click or three. The main display of the APx software also includes a quick view panel for level bargraphs, a soft oscilloscope display, reading bargraphs, etc. With a click, these panels are blown up for closer scrutiny.

In short, the APx measurement software is fast, effective, and full-featured. It’s easy to use for a novice without at all being tedious for a power user. But, the software is nothing without hardware, and the APx series offers a new physical platform as well. The APx comes in 2-, 4-, 8-, and 16- channel versions (I spent time with the APx585 8-channel version), and the series shines in its interface capability. There’s the usual balanced analog (on DB25 connectors for multichannel), unbalanced analog and, optionally, AES3/SPDIF/TOSLink digital I/O (192 kHz sampling capable). Option modules also allow APx hardware to interface at the component level with multichannel signal generation and test in a range of chip level formats such as I2S. Along with support for the scientific programming environment, LavVIEW, and Dolby and DTS compliance testing, the APx is the only direct HDMI audio analyzer available.

You can read all about the testing capability and specs for the APx series online, and even download the software (PC only) and check it out in demo mode, sans hardware. The full range of traditional audio tests including an effective battery of “chirp”-based (fast sweep to allow distortion measurement) acoustic transducer testing is included. A new option, announced at AES and not available for my tests, offers an amazing 1 MHz-wide FFT analysis, taking the test band into the realm of digital clocks and other potential nasty influences.

The SYS-2722 test set still leads AP’s products in low-level and low-distortion performance, but the APx series is no slouch, (the APx525 delivers -105 dB or better THD + N residual and -110 dB with the AG52 high-performance analog option installed) technically outperforming most (AP says all) of the competition, with interface options applauded by designers and manufacturers. The measurement and control software is as innovative as it is easy to use. And, it’s more affordable than the 2700 series (contact AP for pricing). The stuff geek dreams are made of.

Contact: Audio Precision |

Frank Wells is the editorial director of Pro Audio Review.