AP - The Recognized Standard In Audio Test

APx52x Series DownloadsHOME/DOWNLOADS/APx52x SERIES

 

APx525

All related files for APx520, APx521, APx525 and APx526.

All APx instruments use the same APx500 software, however, some features require certain hardware, for example the DSIO option or Digital I/O. Therefore, not every download displayed here will work with every model of APx.

 

About AP Specifications

AP specifications in hard copy booklets & brochures can be out of date. The specifications documents available for download from our Web site have the most current and correct information. If there is a conflict between printed and online specifications, the online version is the prevailing document.

API Development Tools (9) Configuration Files (2) Datasheets (14) Dolby Compliance Projects (0) Software (4) Technotes and AP Applied (23) Test Signals and Waveforms (12) User Manuals and Specifications (4) Utilities, Projects, & Macros (35) Whitepapers, Articles, and Books (10)

API Development Tools

APx API Developer Tools v3.4 (View previous versions)

Resources for API developers. Includes VB.NET and C# templates and example code, C++ examples, LabVIEW examples, and the APx Wavereader dll. Documentation includes Intro to Programming the APx500 API and the APx API Browser. The APx LabVIEW driver is a separate download.

Included in this download:
What's New in the APx500 API
Introduction to Programming the APx500 API
API Browser application

 

APx API Wrapper (for VEE, MATLAB) v2.4

This APx API wrapper dll enables you to access the entire APx API when using Agilent VEE and The Mathworks MATLAB. A discussion and instructions are in the kb article "Using APx with VEE." This download is only necessary for APx500 v2.4. APx500 v2.5 and later already include it.

 

APx Introduction to Programming the APx500 API v3.4

A guide to using the APx500 API, updated for the current version.

 

APx LabVIEW Driver v3.4.3 (View previous versions)

The APx LabVIEW Driver is a collection of Virtual Instruments (VIs) that provide LabVIEW users with most of the functionality available in the APx500 Application Programming Interface (API) using high level, LabVIEW-typical subVIs. With the driver, you can quickly and efficiently develop APx applications with clean, concise LabVIEW code. Please note that the LabVIEW Driver is specific for each release of APx500.

Driver v3.4.3 is for APx500 v3.4.3 or later.

This version of the APx LabVIEW Driver is for users who have LabVIEW 2009 or later. If you have LabVIEW 8.5, download the APx LabVIEW Driver for LabVIEW 8.5 instead.

 

APx LabVIEW Driver for LabVIEW 8.5 v3.0.2

This version of the APx LabVIEW Driver is for users who have LabVIEW 8.5. If you have LabVIEW 2009 or later, we recommend downloading the standard APx LabVIEW Driver for LabVIEW instead.

The APx LabVIEW Driver is a collection of Virtual Instruments (VIs) that provide LabVIEW users with most of the functionality available in the APx500 Application Programming Interface (API) using high level, LabVIEW-typical subVIs. With the driver, you can quickly and efficiently develop APx applications with clean, concise LabVIEW code. Please note that the LabVIEW Driver is specific for each release of APx500.

 

APx Python Sample Code

IronPython is a version of Python that can interface with .NET Assemblies. This download includes an APx Project and a Python code sample that controls APx500 via the APx API.

 

APx VEE Example

An Agilent VEE example that opens APx500, makes settings, and runs an acquisition. For more details about controlling APx500 using VEE, read the associated kb article. After downloading, open in a text editor and modify the .NET references to refer to your current version of APx500.

 

APx WaveReader DLL v3.4 (View previous versions)

The WaveReader DLL provides functions that can be called from an external program, to enable transfer of acquisition data from an APx analyzer to that program in near real time. Any .NET compliant language such as C#, VB.NET, or LabVIEW can make use of it.

 

APx What's New in the APx500 API v3.4 (View previous versions)

A brief description of changes made in the most recent release of the APx500 API.

 

Configuration Files

APx Digital Serial I/O (DSIO) Configuration Files v3.4 (View previous versions)

APx Digital Serial I/O configuration files for A/D, D/A, and sample rate converters. Simplifies configuring the analyzer. Requires: 1) APx500 measurement software and 2) an APx instrument with the DSIO option installed.

 

APx HDMI EDID Configuration Files v3.4 (View previous versions)

APx with HDMI supports multiple EDID configurations. These .edid files are pre-configured for various audio formats including encoded audio such as DTS. Requires APx585 with HDMI hardware. Please consult APx User Manual for more information.

 

Datasheets

APx Bluetooth Option Datasheet v1.3

The APx Bluetooth® option is the best solution in the world for testing audio over Bluetooth wireless technology. No other analyzer combines integrated Bluetooth controls with APx’s best in class speed, ease-of-use, and performance.

 

APx Digital Serial I/O Datasheet v2

Audio Precision’s new Digital Serial I/O for APx audio analyzers provides multichannel, chip-level connectivity for designers of HDMI receiver/ transmitter chips, converters and other micro-components. Innovations include 8 channels of simultaneous audio data, independent clocks, buffered oscilloscope monitors, and built-in support for left or right justified, I2S and DSP formats. 

 

APx PDM Datasheet v3

APx 525 and 585 family PDM option datasheet.

Available translations

 

APx500 Series Audio Analyzers - Comparison Sheet vv1

A two-page overview of the APx500 Series audio analyzers, including summary specification comparison tables.

 

APx500 Software Options Datasheet vv1

Two page datasheet describing the APx500 software, including standard features and measurements along with additional software options.

 

APx525 Family Datasheet v2.0

The APx525 family combines an award-winning user interface with AP’s legendary commitment to performance. APx is high speed, high performance, and user friendly.

Datasheet for models APx525 and APx526.

 

CAB-520 Description v1

 

CAB-525 description v1

 

CAB-DB9 description v1

 

CAB-DSIO description v1

 

Electro-Acoustic Options Datasheet v1.0

A single sheet description of APx Electro-Acoustic software options, including Thiele-Small characterization, Rub & Buzz detection and Loudspeaker Production Test.

 

Perceptual Audio Test Datasheet v2.0

Datasheet for APx PESQ and POLQA software options

 

Dolby Compliance Projects

No files in this category

 

Software

APx500 Measurement Software v4.0 (View previous versions)

APx500 measurement software for all APx Series instruments.

This download is suitable for most users. If Microsoft .NET version 4.5 is not already on your PC, it will be downloaded during the installation.

For PCs that do not have .NET version 4.5 installed, and are not connected to the Internet, download the full installer instead (APx500 Measurement Software (with .NET)) NOTE: .NET 4.5 does not support Microsoft Windows XP.

 

APx500 Measurement Software (with .NET) v4.0 (View previous versions)

APx500 Measurement Software for all APx Series instruments.

This download includes the Microsoft .NET Framework version 4.5, and is suitable for installation on PCs that are not connected to the Internet and do not already have version 4.5 installed. NOTE: .NET 4.5 does not support Microsoft Windows XP.

For installation on Internet connected PCs, download APx500 Measurement Software instead.

 

APx500 USB Drivers Update v3.4.3

APx500 USB Drivers Update
This update is for users of APx500 v2.3 and higher running on Windows Vista, 7, and 8.

Apply this update if you encounter the following symptoms:


* During installation of APx500 on Windows Vista, 7, or 8, you receive one or both of the following warnings:
- User Account Control (UAC) warning “Do you want to allow the following program from an unknown publisher to make changes to this computer?”
- Windows Security warning “Windows can’t verify the publisher of this driver software”.

* APx500 fails to recognize an attached APx analyzer, runs only in “demo mode”.

Download this update and run it after installation of APx500, then power-cycle the attached APx analyzer to restore full functionality.

 

APx500 What's New v4.0 (View previous versions)

Describes new features in the latest release of the APx500 measurement software.

 

Technotes and AP Applied

AP Applied: APx Automation with LabVIEW v1

Describes using LabVIEW with APx in a lab or automated production environment. Examples using the APx LabVIEW virtual instrument driver are shown.

 

AP Applied: Acoustic Response v0

A look at some of the important features needed in an acoustic audio analyzer, the problems you may encounter in non-ideal testing environment, the needs of good production line testing, and the range of measurements and results that should be produced.

 

AP Applied: Digital Protocol Analysis

Explains the various ways to view, measure, and manipulate digital metadata, primarily over the HDMI interface.

 

AP Applied: Production Test v1

Cost benefit analysis of high performance, low price audio test equipment in production.

 

AP Applied: Serial Digital Measurements with APx v1

Serial digital signal analysis is essential in research and development for evaluating audio circuit designs at the chip and at the board level. This AP Applied reviews serial testing procedures, and describes the abilities of the DSIO for APx, as well as the PSIA-2722 for the 2700 Series.

 

AP Applied: Ultra-High Bandwidth Analysis v0

A look at the traditional ways of examining out of band noise signals, as well as the advantages of using an ultra-high bandwidth audio analyzer with full 24 bit FFT resolution from DC to beyond 1 MHz.

Available translations

 

Technote 104: Introduction to the Six Basic Audio Measurements

Technote 104 discusses methods of making a set of basic measurements using an Audio Precision 2700 Series or ATS-2 audio analyzer.These are Level Frequency Response THD+N Phase Crosstalk Signal-to-Noise Ratio

Available translations

 

Technote 105: FM Radio Receiver Testing with APx Audio Analyzers v0

In this technote, we discuss how to test the analog sound quality of FM radio receivers using an Audio Precision APx500 Series audio analyzer. We also discuss how to test the Radio Data System (RDS), which allows text, such as song title and artist, to be transmitted digitally as part of the analog radio signal.

 

Technote 106: Measuring PSRR (Power Supply Rejection Ratio) v0

In this technote we describe and compare two different methods to measure PSRR. Then we give instructions for using the APx PSRR Measurement Utility, which simplifies the calculations and graphing on APx analyzers.

This technote is included in the APx PSRR Measurement Utility download.

 

Technote 107: Measuring the Sound Pressure Level of Portable Audio Player Headphones v1

Describes how to measure the sound pressure level developed by portable audio players and their associated headphones, according to British Standard / European Norm 50332. Also shown is how to use the APx Portable Audio Player / Portable Headphone Test Utility to facilitate making the necessary measurements with an APx500 analyzer.

Performing the tests described in this Technote requires that you download the APx Portable Audio Player / Headphone Test Utility, which includes the Windows installer, VB.NET source code, and this Technote.

 

Technote 108: PC Audio Testing v0

This Technote discusses the techniques necessary to perform the “Basic Six” audio measurements on consumer-level PC audio devices. This category includes sound systems integrated into notebooks, netbooks, tablets, and PC motherboards, as well as expansion cards and some external devices. It doesn’t include USB-connected headsets, nor pro-audio devices with balanced input and output connections.

Includes APx project and .wav test signal files for playback

 

Technote 109: System One DOS Migration to APx v0

Addresses conversion of tests and procedures written using AP’s DOS S1.EXE software for System One to APx500. If you are using AP’s Windows based APWin, AP2700, or ATS software with one of our legacy products, please refer to Technote 110 instead.

 

Technote 110: Legacy Instrument Migration to APx v0

Addresses conversion of tests and procedures/macros written using AP’s Windows based APWin, AP2700, or ATS software to APx500. If you are using AP’s DOS based S1.EXE software for System One, please refer to Technote 109 instead.

 

Technote 111: Testing USB Headsets v1

This Technote discusses techniques for testing the audio performance of USB headsets using an Audio Precision APx analyzer. Includes APx projects and wave files.

 

Technote 112: Windows Logo Audio Fidelity Testing v1

This Technote and its associated APx projects and waveforms allow confidence testing of computer audio systems for compliance with the Microsoft Windows Logo program in a rapid and efficient manner.

 

Technote 113: Measuring Sound Pressure Level with APx v1.1

Acoustic sounds or noise in the environment is typically measured with a handheld sound level meter. This Technote explains some of the theory behind such measurements, and how to make them instead using an APx analyzer. Using the analyzer adds the capability to perform spectrum analysis, and to visualize the character of the sound signal over time. The latter is especially valuable when measuring non-steady state sounds, such as a pulsating alarm. Requires the APx Sound Level Meter Utility, available as a separate download, to make the measurements.

 

Technote 114: Measuring Phantom Power v1

Describes how to test microphone preamplifier phantom power, with and without simultaneous audio. You may instead download the "APx Phantom Power Measurement Project," which runs the tests (that download also includes this Technote).

 

Technote 115: Measuring Microphone Preamplifier Noise

Making noise measurements of microphone preamplifiers (and other high-gain circuits) involves special techniques that differ from those used to measure low-gain devices. This technote explains the theory as well as how to make these measurements.

 

Technote 116: Testing Smartphones and Tablets v1

Smartphones and tablets provide many ways to route audio. This technote shows you how to make connections and test the sound quality for a variety of these signal paths. Where possible, we will use file-based test signals and recordings to measure the quality of signal paths so that we are not measuring the impairments of multiple paths simultaneously.

Includes the accompanying APx project file. The associated APx Smartphone and Tablet Video Test Files and APx Smartphone and Tablet Audio Test Files may be downloaded separately.

 

Technote 117: Measuring PDM Microphones and Inputs with APx v2

This Technote has a short review of how PDM works, describe relevant audio tests, looks at the APx PCM module, and conclude with hands-on testing of a PDM MEMS microphone and a PDM microphone input.

 

Technote 118: Measuring Jitter with J-Test

 

Technote 120: Smartphone Audio Test App for Android v3.4

This technote describes how to install the necessary software on the smartphone or tablet device under test (DUT), how to use the Smartphone app on the DUT, and which APx projects to use for testing the various signal paths. Package containing: 1) The APx Smartphone Audio Test app for smartphones and tablets running the Android OS version 4.0 or higher. 2) Associated APx project files 3) Technote TN120: Using the APx Smartphone Audio Test App.

 

Technote 20: Return Loss Measurements

This Technote gives an overview of the concept of return loss in telephony. Return loss is an expression of the impedance mismatch in a transmission circuit which can give rise to reflection of signal energy. Sample hybrid circuits and their use in return loss measurements using Audio Precision instruments are described.

 

Test Signals and Waveforms

APx DTS Generator Waveforms: DTS Digital Surround v1

The APx DTS Generator Waveforms support the APx500 generator waveform feature and are encoded in the various DTS surround sound formats. Copy the folders to your PC and browse to the desired file from the Generator Waveform browser inside the APx500 application.

Notes: These files are similar to the files of the same name and format available on the APx-BD1 Blu-ray disc. Some files have been shortened to accommodate the memory limitation for the generator waveform feature. A few files that could not be shortened have been omitted.

 

APx DTS Generator Waveforms: DTS HD High Resolution v1

The APx DTS Generator Waveforms support the APx500 generator waveform feature and are encoded in the various DTS surround sound formats. Copy the folders to your PC and browse to the desired file from the Generator Waveform browser inside the APx500 application.

Notes: These files are similar to the files of the same name and format available on the APx-BD1 Blu-ray disc. Some files have been shortened to accommodate the memory limitation for the generator waveform feature. A few files that could not be shortened have been omitted.

 

APx DTS Generator Waveforms: DTS HD Master Audio v1

The APx DTS Generator Waveforms support the APx500 generator waveform feature and are encoded in the various DTS surround sound formats. Copy the folders to your PC and browse to the desired file from the Generator Waveform browser inside the APx500 application.

Notes: These files are similar to the files of the same name and format available on the APx-BD1 Blu-ray disc. Some files have been shortened to accommodate the memory limitation for the generator waveform feature. A few files that could not be shortened have been omitted.

 

APx Dolby Generator Waveforms: Dolby Digital v1

The APx Dolby Generator Waveforms support the APx500 generator waveform feature. Copy the folders to your PC and browse to the desired file from the Generator Waveform browser inside the APx500 application.

Notes: These files are similar to the files of the same name and format available on the APx-BD1 Blu-ray disc. Some files have been shortened to accommodate the memory limitation for the generator waveform feature. A few files that could not be shortened have been omitted.

 

APx Dolby Generator Waveforms: Dolby Digital Plus v1

The APx Dolby Generator Waveforms support the APx500 generator waveform feature. Copy the folders to your PC and browse to the desired file from the Generator Waveform browser inside the APx500 application.

Notes: These files are similar to the files of the same name and format available on the APx-BD1 Blu-ray disc. Some files have been shortened to accommodate the memory limitation for the generator waveform feature. A few files that could not be shortened have been omitted.

Download of this file is restricted to Dolby Licensees. If you are a Dolby licensee, please contact Audio Precision Technical Support supplying your Dolby License and AP web site login name to obtain download permissions.

 

APx Dolby Generator Waveforms: Dolby TrueHD v1

The APx Dolby Generator Waveforms support the APx500 generator waveform feature. Copy the folders to your PC and browse to the desired file from the Generator Waveform browser inside the APx500 application.

Notes: These files are similar to the files of the same name and format available on the APx-BD1 Blu-ray disc. Some files have been shortened to accommodate the memory limitation for the generator waveform feature. A few files that could not be shortened have been omitted.

Download of this file is restricted to Dolby Licensees. If you are a Dolby licensee, please contact Audio Precision Technical Support supplying your Dolby License and AP web site login name to obtain download permissions.

 

APx FM MPX-RDS Waveforms 50µs (except North America) v1

APx FM MPX-RDS Waveforms 50µs (except North America) contains a series of FM multiplex and RDS encoded waveforms for FM radio receiver testing with the APx Series analyzers. The test streams are versions of the stereo .wav files that can be created with the Audio Precision Waveform Generator Utility (WfmGeneration.exe), also available for download.

Copy the folder to your PC and load the desired file using the generator waveform browser inside the APx500 application. Download Technote 105: FM Radio Receiver Testing with APx Audio Analyzers for a discussion on FM testing.

 

APx FM MPX-RDS Waveforms 75µs (North America) v1

APx FM MPX-RDS Waveforms 75µs (North America) contains a series of FM multiplex and RDS encoded waveforms for FM radio receiver testing with the APx Series analyzers. The test streams are versions of the stereo .wav files that can be created with the Audio Precision Waveform Generator Utility (WfmGeneration.exe), also available for download.

Copy the folder to your PC and load the desired file using the generator waveform browser inside the APx500 application. Download Technote 105: FM Radio Receiver Testing with APx Audio Analyzers for a discussion on FM testing.

 

APx Smartphone and Tablet Audio Test Signals v2

A comprehensive set of audio test files at 8k, 16k, 44.1k, and 48k sample rates for testing smartphones and tablets. Accompanies Technote 116: Testing Smartphones and Tablets, which is a separate download.

APx Smartphone and Tablet Video Test Files is also available.

 

APx Smartphone and Tablet Video Test Signals v3

A comprehensive set of MP4 video files with audio encoded in AAC, Dolby Digital 2.0, Dolby Digital 5.1, and Dolby Digital Plus 5.1 formats. Accompanies Technote 116: Testing Smartphones and Tablets, which is a separate download.

APx Smartphone and Tablet Audio Test Files is also available.

 

APx Test Signals on Disc Track List v3

The full track listings for all APx test signal discs – APx-BD1, APx-DVD1, and APx-CD1. These discs may be ordered from Audio Precision.

Alternately, the linear test signals may be created using the APx Waveform Generator Utility (available as a download), and the Dolby and dts encoded versions may be downloaded as "APx Dolby Generator Waveforms" and "APx dts Generator Waveforms" respectively.

 

APx Waveform Generator Utility v4.2

The Waveform Generator Utility (APxWfmGenerator.exe) allows you to generate .wav files for a wide range of test signals, with selectable sample rates, bit depths and channel counts.

You are free to copy this utility to other computers or media, where you can generate the audio files you may need for external source testing.

Note that the version number of this utility does not correspond to APx500 software versions and APx500 is not required.

 

User Manuals and Specifications

APx PDM Option Specifications v3.1

 

APx500 User Manual v4.0 (View previous versions)

User manual for APx500 measurement software. Includes detail on signal path setup, hardware connectivity, and software features for all APx models: APx515, 520, 521, 525, 526, 585, 586, and 555.

Available translations

 

APx52x Series and APx58x Series Installation Instructions and Full Specifications v4.0 (View previous versions)

Installation instructions and full specifications for APx525, APx582, and APx585 series audio analyzers.

AP specifications in hard copy booklets & brochures can be out of date. The specifications documents available for download from our Web site have the most current and correct information. If there is a conflict between printed and online specifications, the online version is the prevailing document.

 

RAK-APX Rackmount Kit Instructions (all APx analyzers except APx515) v1

 

Utilities, Projects, & Macros

APx Active Loadbox Utility v3.3 (View previous versions)

Integrates APx with AudioGraph’s Active Loadbox for automated and comprehensive power amplifier load measurements. Requires the Active Loadbox hardware for use.

An overview of the measurement principles and detailed usage instructions is contained in the KB article: Measuring Power Amplifiers with Reactive Loads.

 

APx Barcode Scanner Interface v3.2 (View previous versions)

A barcode scanner may be useful in production testing, not only to expedite data entry, but to eliminate the possibility of initiating the wrong test routine. The APx Barcode Scanner Interface is a small VB.net application (Run_Barcode_Project_ID.exe) that automatically loads an APx project who's name matches the barcode data.

 

APx Bode Plot Project v1

An APx project that creates reports in Bode Plot format. Requires APx500 v3.2 or later.

 

APx Burst Waveform Utility v3.4 (View previous versions)

This utility creates sine burst waveforms and then saves them and/or uploads them into the APx generator. Burst waveforms can be useful in testing a number of properties, including power supply transient response and reserve, meter ballistics, and compressor/limiter behavior.

 

APx Click and Pop Measurement Projects

For use with the APx Sound Level Meter Utility. See the associated KB article on Click and Pop Measurement for full discussion and instructions.

 

APx Damping Factor Measurement Utility v3.4 (View previous versions)

The APx Damping Factor Measurement Utility plots audio amplifier damping factor vs. frequency. It is developed in LabVIEW 2009, but does not require that you have LabVIEW to run. See the accompanying knowledge base article for an explanation and instructions.

Includes the Windows installer, source code, and instructions.

The version number of this utility must match the version of the APx software that you are running.

 

APx EQ .wav Files Utility v1.03

The APx EQ .wav Files Utility lets you apply equalization to generator source .wav files. When given an original .wav file and an EQ curve file, it creates a new EQed .wav file. Includes both graphic interface and command line versions. The utility is useful to EQ PESQ generator files for a given stimulus speaker. Download includes instructions. Note that any version of APx500 may be used with this utility, and version numbers do not correspond to APx500 versions.

 

APx Equalized THD Measurement Utility v1.0

This utility allows you to calculate post equalization THD on-the-fly. The utility operates from the command line (no user interface) and is called during an APx project by adding a Program step to the sequencer. Includes complete instructions and project file.

 

APx FFT to Octave Conversion Utility v3.4 (View previous versions)

Converts FFT spectra to fractional octave spectra. Includes instructions which discuss the theory behind the conversion.

 

APx FM MPX-RDS Demo Project v1

A simple APx project file to demonstrate testing of FM transmitters and receivers, including automotive head units. Includes a set of MPX-RDS-encoded sweeps and tones.

 

APx FM MPX-RDS Waveform Creation Utility v3.4 (View previous versions)

This utility can create a file containing a multiplexed and RDS encoded waveform of stereo sine waves, and upload it to the APx500 measurement software. Accompanies Technote TN-105, "FM Radio Receiver Testing with APx Audio Analyzers." The MPX-RDS FM utility is written with LabView. This download is for users both with and without LabView installed. For those users who do not have LabView, a run-time version will be installed with the utility.

 

APx Generator EQ Files v1

These files can be used with APx500 v2.7 or later to create equalized sweeps or equalized multitones.

Included are RIAA, FM 50uS, and FM 75uS emphasis and de-emphasis curves.

 

APx J-Test (Jitter) Measurement Utility v3.4 (View previous versions)

Measures jitter at the receiving end of an AES3/SPDIF connection by using a special J-test stimulus signal and analyzing the analog output spectrum. Displays graphs showing the FFT spectrum, the jitter spectral density, and the integrated jitter, in addition to a total jitter value. Tools are included for manipulating the graphs, exporting data, and printing.

Download includes the utility, J-test stimulus waveforms, and instructions. The utility version must match the version of APx500 that you are running.

 

APx Mixing Console Sample Project v1

APx mixing console sample project with instructions. Requires any APx instrument.

 

APx Multichannel Amplifier Power Output Sample Project

APx sample project for measuring the power output of a multichannel amplifier according to EIA/CEA-490-A, section 6.1, where non-measured channels are attenuated by 9 dB. A related KB article includes an explanation of the measurement.

 

APx Output Impedance Measurement Utility v3.4 (View previous versions)

The output impedance of a device can easily be calculated by measuring its output voltage with and without a known load attached. The APx Output Impedance Measurement Utility simplifies the procedure by calculating and graphing the results. It is developed in LabVIEW 2009, but does not require that you have LabVIEW to run. See the accompanying knowledge base article for an explanation and instructions.

The version number of this utility must match the version of the APx software that you are running. Includes the Windows installer, source code, and instructions.

 

APx Phantom Power Measurement Project

Allows measurement of phantom power on a microphone preamplifier, with and without a simultaneous audio signal. Requires a special Phantom Power Test Fixture, described in Technote 114: Measuring Phantom Power (included).

 

APx Polar Plot Utility v3.4.1

The APx Polar Plot Utility is a Windows application for making polar measurements of loudspeakers or microphones with an APx500 audio analyzer and for creating 2-dimensional polar dispersion plots from the measured data. The APx Polar Plot utility also requires the SPK or SPK-RD software option to be installed on the connected APx audio analyzer. If you require a SPK-RD software option, please contact your Audio Precision sales representative.

 

APx Portable Audio Player / Headphone Test Utility v3.4 (View previous versions)

Tests portable audio players and headphones packaged as a set, and as individual components, for compliance with the BS EN 50332 standard. Works with any APx Series analyzer. The version of APx500 software must match the utility version. Includes the Windows installer, VB.NET source code, and Technote 107 with full instructions.

 

APx Power Amplifier (Linear) Sample Project v1

APx power amplifier (linear) sample project and instructions. Requires any APx instrument.

 

APx Repeat Measurement Utility v3.3 (View previous versions)

The APx Repeat Selected Measurement Utility allows you to continuously repeat any selected APx500 measurement. This is useful when adjusting a device, circuit, or component on the bench and you want to monitor changes as you make them in real time.

Download includes installer and instructions. The utility version must match the version of APx500 that you are running.

 

APx Reports Tutorial A Files v1

The files created while doing "Tutorial A: Making a Custom layout from the Default layout" in the APx500 program Help. Use these files if you wish to skip Tutorial A and proceed with Tutorials B and C.

 

APx Run External Program Project v1

This APx project and related files demonstrates how to run an external program from APx500. Includes THD+N measurement and Stepped Frequency Sweep measurements. The project file calls the Goldwave audio editor program, so you will either need to install Goldwave, or substitute another audio player with a command line interface. Accompanies the kb article "Running an external program from APx500," which gives a complete explanation.

 

APx Self Test v3.4 (View previous versions)

Automated self test for all APx instruments. Run this test to confirm proper operation and before sending an instrument in for service.

 

APx Sound Level Meter Utility v3.4 (View previous versions)

Allows an APx500 Series Analyzer to measure acoustic noise or sound in the environment, taking the place of a handheld sound level meter. Using the analyzer adds the capability to perform spectrum analysis, and to visualize the character of the sound signal over time. The latter is especially valuable when measuring non-steady-state sounds, such as a pulsating alarm. Technote 113, included, describes the theory and how to use the utility.

 

APx Speaker Impedance Measurement Project

This project measures loudspeaker impedance using the constant voltage method.

Complete instructions and explanation are in the KB article "Measuring Loudspeaker Impedance Using APx Derived Measurement Results".

An external sense resistor is required for this project. The "APx Speaker Impedance Measurement Utility," also available for download, can utilize the built-in source resistor in APx analyzers.

 

APx Speaker Impedance Measurement Utility v3.4 (View previous versions)

This utility for APx analyzers allows you to make an impedance vs frequency sweep across a loudspeaker, and then see the graph and data results directly in ohms. Clicking Help in the utility will display the complete instructions, including a discussion of the theory behind it. This download includes the compiled utility application (LabVIEW not required to run), as well as the LabVIEW 2009 source code.

This utility can utilize the built-in source resistor on APx analyzers to make impedance measurements. The "APx Speaker Impedance Measurement Project," also available for download, requires an external sense resistor and uses the constant voltage method.

 

APx Splice Utility v1.01

Splice is a CLI utility that combines separate LF and HF measurements into a single full frequency response result.

 

APx THD Sweep Individual Harmonics Project v3.0

Produces a separate trace for each harmonic H2 through H10 (can be extended to H20), as both a level and as a ratio, and displays them all on one graph. Each harmonic can easily be enabled or hidden. Makes use of the Export Data and Import Data steps in the automated project sequencer. I/O connectors and measurement bandwidth should be set in Signal Path Setup before running. This project will open in APx500 v3.0 or later.

 

APx Waterfall-CSD Plot Utility v3.4

The APx500 CSD Utility is a Windows application for making a Cumulative Spectral Decay (CSD) plot, sometimes referred to as a waterfall plot, from the measured impulse response of a loudspeaker. The APx CSD utility also requires the SPK-RD software option to be installed on the connected APx audio analyzer. If you require a SPK-RD software option, please contact your Audio Precision sales representative.

 

APx Waveform Computes Utility v1.0

The APx Waveform Computes Utility extends the capabilities of APx500 by making Fast RMS (root mean square) measurements. Additionally, it utilizes Fast RMS for a number of useful tasks: audio/video synchronization, dropout detection, and pop/click detection. Download includes utility, instructions, and example project file.

 

APx Wow and Flutter Measurement Utility v3.4.1 (View previous versions)

Enables an APx500 audio analyzer to measure wow and flutter, according to standard “AES 6-2008—Method for Measurement of Weighted Peak Flutter of Sound Recording and Reproducing Equipment” (IEC 60386 Weighted). Includes an FFT of the demodulated waveform, as well as an unweighting option.

 

Matlab Toolbox v5.1

Set of MATLAB functions for audio applications such as reading and writing waveforms and filters for 2700, ATS-2, and APx

 

Using the APx Smartphone Test App (Technote 120) v1.0

Describes and explains the use of the APx Smartphone app for Android-based devices. This app allows for full testing of audio pathways, including Bluetooth(R) HFP and A2DP, without initiating a call over the network.

 

Whitepapers, Articles, and Books

APx PDM Option Technical Details

 

Decoupling Capacitors by Kendall Castor-Perry v1.0

An in-depth look at the behaviors of decoupling schemes in power supply designs for audio.

 

Fast Audio-Band Measurement Using Log-Swept Chirp Signals

Fast Audio-Band Measurement Using Log-Swept Chirp Signals by Dr. Tom Kite, AP VP of Engineering

 

How to Write (and Read) Audio Specifications

Discusses writing and reading good audio specifications. Guidelines are provided, then key specifications for two classes of audio device are examined for correct expression and form, with examples of real-world specs for comparison.

 

Limitations in making audio bandwidth measurements in the presence of out of band noise

Audio analyzers are optimized to make high quality measurements up through their maximum specified bandwidths. The presence of significant energy above these bandwidths can have a profound effect on the audio measurements and possibly induce errors. This white paper provides valuable information on avoiding the possibility of errors when testing digital to analog converters and other audio devices that contain significant energy above the audio band. Written by Bruce Hofer

 

Measuring Digital Audio

Transmitting and storing audio signals in the digital domain is well-established in the broadcast industry. Analog audio has given way to the AES3 and Sony/Philips Digital Interface Format (SPDIF). AES3 data streams are also embedded in SDI television signals. Handling audio in the digital do- main offers many advantages over analog methods. An analog signal incurs progressive degradation as it passes through a chain of circuits. Converting the analog signal into digital and converting back to analog as late in the chain as possible overcomes this degradation.

 

Measuring Distortion in Switching Amplifiers

Measuring Distortion in Switching Amplifiers by Bruce Hofer

 

Measuring Switch-mode Power Amplifiers

Switch-mode audio power amplifiers are becoming increasingly popular due to their smaller size, lower weight, and improved efficiency. Their advantages are obvious in low power battery operated personal audio players and laptop computers. However they are also progressively displacing more traditional linear designs in mainstream applications such as home entertainment systems, automotive sound systems, and professional installations where high quality audio is important. Measuring the performance of switch-mode amplifiers presents some new and unique challenges. They inherently generate ultra-sonic artifacts and spurious signals with slew rates that can provoke non-linear behavior within the input stages of high quality audio test and measurement equipment. Absolutely worthless and inaccurate results can result unless effective measures are taken to prevent this non-linear behavior. Written by Bruce Hofer.

Available translations

 

Testing Challenges in Personal Computer Audio Devices

The Personal Computer audio environment has evolved over the years to become a significant entity within the field of acquisition and rendering of audio information. The personal computer is a highly sophisticated interactive environment that is much more complex than a conventional dedicated home audio device, leading to new problem areas. These include, but are not limited to, stochastic interrupts, network accesses, disc I/O and disparate hardware qualities. While the environment of a highly matrixed multi-tasking concurrent operating system offers many opportunities to overcome quality issues, the PC, due to the media-rich tools and feature sets, is becoming the entertainment capture and rendering device of choice for future generations. Presented at the 114th Convention, 2003 March 22–25 Amsterdam, The Netherlands. Wayne Jones, Michael Wolfe, Theodore C. Tanner Jr., Daniel Dinu

 

The Audio Measurement Handbook v1

This reference handbook is a practical, hands-on guide for workers in all phases of the audio field. It covers basic tools and techniques, common environments for audio testing, application of these techniques to common audio devices, the typical ranges of performance to expect in different devices, and a glossary of terms and key specifications used in audio measurement. 178 pages Written by Bob Metzler.

Available translations

 


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