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APx52x Series Audio AnalyzersHOME/PRODUCTS/APx SERIES/APx52x Series

Modular 2- and 4-Channel Performance
Audio Analyzers

The ideal balance of analog performance and breadth of digital I/O.


The APx525 is a two channel audio analyzer for R&D engineers and production technicians who want fast and easy audio test, but who may not need the ultra-high performance of AP’s APx555 nor require the multichannel capability of the APx585.

APx525 has two balanced and two unbalanced analog inputs and outputs plus 216k digital inputs and outputs via AES/EBU, TOSLINK and SPDIF. APx526 is the four channel version of the APx525, developed for the 4 channel head units typical of the automotive audio industry.

Additionally, I/O may be expanded with optional Digital Serial (APx525 and APx526), HDMI with ARC (APx525), PDM (APx525 and APx526) and Bluetooth (APx525 and APx526) modules.

Developed for power amp designers, the AG52 analog generator option generates exceptionally clean square waves with a rise time better than 2 microseconds and has an improved THD+N of -110 dB (typical). The AG52 generates DIM 100, 30, and B square + sine waveforms and maximum output level is increased from 21.21Vrms to 26.66 Vrms (balanced).

The BW52 ultra-high bandwidth option offers unprecedented FFT performance: 1.248 million points, DC to 1 MHz bandwidth and full 24-bit resolution. Ideal for Class D amplifier design and unmatched by any other test instrument.

There is no need to compromise

The APx52x Series offers unbeatable performance and value.

Wide range and low noise
New breakthroughs allow APx to generate signals all the way down to 0.1 Hz. Maximum input voltage is rated at 230 Vpk and typical THD+N is −108 dB (at 1 kHz, 2.5 V). No other analyzer in the mid-range class offers this level of performance.

Made to measure for power amp designers
Measure continuous maximum output and peak maximum output automatically, DIM measurements, view power spectrum graphs with a regulated frequency sweep and take other measurements as specified by the CEA-2006 and CEA-490A standards. In addition to conventional balanced common mode rejection measurements, APx525 is also capable of performing CMRR measurements in accordance with IEC60268 section 14.15.1.

Sharing projects
All settings for a test are saved in a single project file that’s small enough to email, making it easy to replicate test setups between R&D and production facilities anywhere in the world. Project files are compatible with all APx instruments and each project is self-contained, so there’s never any worry about dependencies or broken links.

Reporting results
For customers, contract manufacturers or management, APx automatically generates rich graphic reports, with highlighted pass / fail limits and options to export as PDF, HTML, Excel or text.

High performance

  • –108 dB Typical THD+N
  • Up to 216k digital connectivity
  • Supports legacy AP switchers

Easy automation

  • Automation without a single line of code with Sequencer
  • VB.NET, C#.NET, MATLAB, and LabVIEW support in API
  • Read more ...

What others are saying

“[With the APx525] Audio Precision has produced an instrument that will be hard to beat for the price.”
-- Graham Langley | Audio Media

Audio Media Magazine

Ideal for testing

The APx52x Series is an excellent choice for most analog and digital audio applications (unless you need the ultra-high performance of the APx555).

  • Power amps
  • Automotive head units
  • Stereo receivers
  • Converters
  • MP3 players
  • CD / DVD players
  • Televisions
  • Broadcast test
  • Facility service
  • Digital Interfaces






    Download full specifications

  • Sine Frequency Range
    0.1 Hz to 80.1 kHz
  • Frequency Accuracy
    2 ppm
  • IMD Test Signals
  • Maximum Amplitude (balanced)
    21.21 Vrms
  • Amplitude Accuracy
    ±0.03 dB
  • Flatness (20 Hz–20 kHz)
    ±0.008 dB
  • Residual THD+N (20 kHz BW)
    –105 dB + 1.4 µV
  • Analog Output Configurations
    unbalanced & balanced
  • Digital Output Sampling Rate
    27 kS/s to 200 kS/s
    27 kS/s to 108 kS/s Optical
  • Dolby / dts Generator
    Yes (encoded file)
  • Maximum Rated Input Voltage
    230 Vpk
  • Maximum Bandwidth
    >90 kHz
    >1 MHz [with BW52]
  • IMD Measurement Capability
  • Amplitude Accuracy (1 kHz)
    ±0.03 dB
  • Amplitude Flatness (20 Hz–20 kHz)
    ±0.008 dB
  • Residual Input Noise (20 kHz BW)
    1.3 µV
  • Residual THD+N (20 kHz BW)
    –105 dB + 1.4 µV
  • Individual Harmonic Analyzer
  • Max FFT Length
    1248K points
  • DC Voltage Measurement

  • PC with 2 GHz or faster multi-core processor (2 or more cores)
    Note: the Intel Atom dual-core processor does not have sufficient performance to run APx software.
  • 2 GB or more RAM (4 GB or more recommended for Windows 7/8).
  • Microsoft Windows XP (32-bit, SP 2 or later), Windows Vista (32-bit), Windows 7 (32- or 64-bit), Windows 8 (32- or 64-bit).
  • More detailed information is available on our
    AP Software and Windows Compatibility chart
  • Download System Requirements Document
  • System performance is sensitive to processor speed; faster processors will yield faster results.
  • APx500 is data intensive and it is recommended that other data-intensive applications not be run concurrently. This includes Audio Precision AP2700, APWIN or ATS.
  • We recommend and support the following specific editions of Microsoft Windows: XP Professional SP2 and SP3, Vista Business and Ultimate, Windows 7 Professional and Ultimate (32- and 64- bit), Windows 8 Pro and Enterprise (32- and 64-bit).
  • Download System Requirements Document

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