The Audio Precision “System One” product family has been out of production since 2002, and is now considered obsolete. Adjustment and repair services, along with replacement parts and/or modules are no longer available from Audio Precision.
System Two is in conditional service.
As a courtesy to those who desire to continue supporting these classic products, Audio Precision hereby provides all the System One references that are available. This information is provided as-is, and without warranty of any kind. Persons attempting to service, repair, or adjust a System One product do so at their own risk.
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LabVIEW VI examples for controlling 2700 Series and System Two Cascade instruments using AP2700 control software and ActiveX automation. For usage instructions, see Technote 101.
This is for controlling type "A" instruments, or type "G" instruments via the APIB bus. For LabVIEW control via GPIB, download the 2700 Series LabVIEW Driver instead. Requires LabVIEW 2009 or higher.
LabVIEW VI examples for controlling System Two and System One instruments using APWin control software and ActiveX automation. For usage instructions, see Technote 101.
For controlling type "A" instruments, or type "G" instruments via the APIB bus. Requires LabVIEW 6.0 or higher.
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High Speed Tester (HST) is a fast, accurate and easy-to-operate audio test application that is ideal for high speed production test or testing transmission quality across a broadcast network.
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Compatible with 2700 Series, System Two Cascade, and System Two Cascade Plus.
Version 3.3 SP2 (and SP1) supports 64-bit Windows 7/8 using the APIB-USB adapter. The OPT-2711 (Dolby Digital generator option) is not supported. Instruments with OPT-2711 installed will function correctly on a 64-bit PC, but the Dolby Digital generator will not be available.
AP2700 v3.30 has an issue with the Import .wav File function, causing file truncation and frequency error correction problems. This can be corrected by replacing the DspRiff4.ocx file in the C:\Program Files\Common Files\Audio Precision folder with this version.
This issue has been corrected in AP2700 v3.30 SP1. We recommend that you download and install SP1 or later instead of just replacing this file, as it addresses some other issues as well as adds a driver for 64-bit versions of Windows.
The Audio Precision Filter Design Package (APFDP) has been produced by Momentum Data Systems, Inc., to allow the user to create DSP filters for downloading to Audio Precision System Two Cascade hardware. The manual below explains the operation of APFDP. It is not intended to be a tutorial on digital signal processing, since there are many excellent texts on the subject, and it is assumed that the user has had a certain amount of academic or professional exposure to the subject. More advanced versions of this software are available, including versions enabling the design of finite impulse response (FIR) filters. These versions also support more powerful filter design techniques. Please call Momentum Data Systems for further information. Zip file contains APFDP manual (.pdf file) APFDP Executable application (.exe file) 4 sample test tiles (.spc file) Read me (.txt file) PLEASE NOTE: This package is no longer supported by AP and is available as a convenience to our customers.
Audio Precision's proprietary APIB interface bus requires the installation of the proper Windows driver software on your PC.
APWIN Control software. For all System One and System Two models.
S1.EXE Control Software for System One. Please note that System One is a legacy product, and we no longer provide technical support or service.
This expansion and revision of the original Audio Precision Compact Disc Player Testing Application Note (AN-1) includes many new test techniques as well as refinements and improvements on the original tests. Test and procedure files supplied with this application note provide new convenience and ease-of-use for testing CD players using these instruments. Files created for both System One and System Two using APWIN are available. Also included are specialized and difficult tests such as distortion at low amplitudes, decoder linearity measured to below the Least Significant Bit, quantization noise, dynamic range, SMPTE and twin-tone (CCIF) intermodulation distortion and Wow and Flutter as an impulse noise test.
The AP High Speed Tester (HST) application was originally developed to test playback only devices on the production line. The objective was a fast, accurate and easy-to-operate test station with a limited graphical user interface that just indicated the test results and had the ability to save results to a log file.
In addition testing play-back devices, HST 2.0 can use the instrument's generator to drive the input of the device under test. Both input and output can be set to digital or analog, and limits, user prompts and sample rate can be defined easily via a new setup utility.
This flexibility allows HST 2.0 to test almost any type of audio device - amplifiers, DACs, ADCs, signal processors, MP3 / DVD players etc. - quickly and easily.
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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.
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
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.
System One SWR series switchers are normally controlled via the APIB interface and S1.exe software. This Technote describes the APIB interface used on the switchers and explains how to control them from a generalized parallel port. A sample BASIC program is included to program the switchers from a PC parallel printer port. This Technote assumes programming and hardware knowledge.
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.
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).
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.
This Technote describes how to set up the PC that controls System One to be able to automatically send a fax to a designated fax machine with the results, in both tabular and graphical form, of the measured data. The measuring PC can be at a remote unattended location as the fax capability can be configured to operate completely automatically on time, event of data out-of-limits conditions. The description shows how to integrate commercial fax modem cards and software.
System One DSP can produce signals based on a stored waveform loaded into its memory. A file with a .wav extension is downloaded to the DSP memory in System One to create the output. A utility called MAKEWAVE.exe is supplied With System One DSP that will convert an ASCII file that contains a time record into the .WAV format for use with the DSP generator. This Technote describes the format of the .waa ASCII files and how to create arbitrary waveforms. It assumes some programming knowledge.
The multimedia expansion in the PC industry has created the need to test the audio performance of sound cards. This is a classic dual-domain application requiring testing of the D-to-A and A-to-D sections. This utility will translate either direction between the Microsoft RIFF .WAV file format and the Audio Precision DSP.WAV file format. This allows a System One test signal created by MAKEWAVE to be played back though the D-to-A, and a captured PC .WAV file to be analyzed on System One.
Reduced bit rate codecs cannot be properly tested using conventional sine wave test signals. Using multitone test signals and FFT analysis, the codec can be stressed to properly characterize how it will perform with program material. CODEC.dsp uses multitone testing techniques and internal automatic masking curve generation to facilitate objective and repeatable evaluation of codecs.
This Technote describes how to setup communication between AP Basic and GPIB instrumentation (using the National Instruments GPIB Interface.)
Conventional analog total harmonic distortion tests are made with a notch filter that removes the fundamental and makes a root sum square summation of all of the harmonics. FFT techniques, on the other hand, provide the absolute amplitude of each individual harmonic. This program will extract the necessary harmonic data and the fundamental amplitude, compute the rss summation and express the result as a conventional THD ratiometric value.
This Technote describes the Makewave utility, an AP Basic procedure that simplifies the process of creating multitone waveform files to use with the analog and digital generators in System One and System Two instruments. The download includes the utility.
You can easily create an HTML-based help system to guide production technicians through APWIN Basic procedures. HTML, or HyperText Markup Language, is the language used by web browsers to format and display web documents. HTML-based help system files can be viewed by anyone with Internet or Intranet access, or they can be local files on a single computer. They can be updated at one location and can grow as your procedures grow. You can save files as HTML from word processors such as Microsoft Word 97, or you can use web development tools such as Dreamweaver or Front Page to create more sophisticated web-based help documents. It is possible to design robust interactive web-based help systems, including such features as displaying animated demonstrations, capturing and distributing information, using a database, and providing web-based training with audio, video, animations, etc.
Describes how to generate Impedance versus Frequency swept data using System One. This is of particular interest to loudspeaker designers where the impedance response can provide very useful information on the performance of a speaker. Includes a BASIC program that does the calculations.
This Technote is a rewrite of Technote #1 to support System One and System Two using Windows APWIN software. An additional method using an external amplifier and current sense resistor is provided.
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.
The Audio Precision System Two's dual channel FFT signal analysis provides an alternate method of obtaining frequency response measurements. With power spectrum averaging of the FFT, the test signal can be regular audio program material. This ability to use music as the test signal can be useful in situations where conventional test signals would be annoying to listeners, such as in broadcasting or live performances. The only requirement for the source program is that it have sufficient energy, over time, at all frequencies in the bandwidth of interest. In other words a rock band or a symphonic orchestra would be a better choice than a single folk singer with a guitar.
This Technote describes how to set up and use the dBr unit as dBSPL. Automated AP Basic macros (procedures) are available to facilitate the calibration. These macros apply to the instrument analog analyzers. Additionally, two computational methods are described to help you understand the macros, and to help you calibrate a measurement microphone without the macros.
Plots of group delay versus frequency are useful in filter design and loudspeaker design applications. This Technote includes a BASIC program that will use a phase versus frequency plot as generated by System One to produce a group delay plot. The BASIC program can be run in a DOS shell within S1.exe.
This APWIN utility allows you to load any .wav files compatible with the Microsoft RIFF file format into APWIN and analyze them in the frequency or time domain.
Some measurement situations place the measurement equipment at some distance from the operator. Many broadcast applications require that System One be located at a distant, possibly unattended site. This Technote describes how to set up a modem communication link between the distant measurement PC and a local operator PC to enable manual or automatic transfer of measured data. The set up for two commercial communication programs, PC Tools Commute and Norton pcAnywhere, are described.
Tests of recorded or transmission media often require an equalized generator signal. Modifying the response of a swept generator to reciprocate the pre-emphasis or de-emphasis characteristics of the device under test will prevent overload and yield a flat response at the output. This Technote includes a BASIC program that will compute a data file based on user supplied time constants. The data file can then be used as an S1.exe EQ curve.
System One produces data files that are two or three columns wide with as many rows as measurement steps. Usually the first column is the source data and columns two and three are measured data. There are some applications where it is desirable to use some data from one file with data from another file to produce a third file. This Technote includes a C program that allows columnar data to be exchanged, moved or combined to produce a new data file.
When several plots of a parameter are acquired, it is often useful to reduce the large volume of data to statistical summaries such as maximum, minimum, average or delta. This Technote includes a program that will operate on an S1.exe nested sweep file to produce the statistical data mentioned above. The program can be run in an S1.exe DOS shell.
S1.exe *.tst files save instrument setups and test data in a binary format for space and speed efficiency. It is possible to examine such a file (or *.lim, *.eq, *.swp and *.ovl files) to extract this data. This Technote explains the internal structure of these files. It assumes intermediate programmers knowledge and is intended as a reference source, not a step-by-step explanation.
System One DSP programs allow a SAVE WAVEFORM operation to store the time record data to disk. This Technote describes the internal structure of the *.wav files so produced. This would allow a knowledgeable programmer to extract data from this file for external post processing. It assumes intermediate programming expertise.
Frequency response measurements on a Multitrack tape recorder are best made by successively measuring each track at the first frequency, then step to the second frequency and measure all tracks, and so on until all frequencies are measured. This produces a nested sweep file that plots amplitude versus track rather that amplitude versus frequency. This Technote contains a program that will restructure such data into the preferred format
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AP Basic Language Manual (previous versions titled: APWIN Basic User's Guide and Language Reference)
APWIN Basic Extensions for System Two
APWIN Basic Extensions for System Two Cascade
APWIN Simplified for System Two Cascade
APWIN User's Manual Addendum for version 2.22
APWIN User's Manual for System Two
APWIN User's Manual for System Two Cascade
S-AES17 Filter User Guide
SIA-2322 Serial Interface Adapter User Manual
SWR-2122 Series Switchers User Manual
System One DSP User Manual for DOS s1.exe software version 2.10a and DSP programs version 14. For S1.exe usage without loading DSP programs, see the separate System One User Manual.
System One Training Quicktime Video. Requires Quicktime player.
System One User Manual for DOS s1.exe software version 2.10a (with addendum for 2.10d). For s1.exe DSP programs, see the separate System One DSP User Manual.
System Two Burst Generator (SBUR) Installation Instructions
System Two Cascade Installation & Getting Started Manual
System Two Cascade Plus Installation & Getting Started Manual
System Two External Filter Installation Guide
System Two Family Filter Installation Instructions
System Two GPIB Installation Manual
System Two GPIB Programmer's Reference Manual
System Two Installation & Getting Started Manual
System Two Intermodulation Analyzer (SIMA) Installation Instructions
System Two Intermodulation Generator (SIMG) Installation Instructions
System Two Optional Filter Installation Guide
System Two Rackmounting Instructions
System Two Wow & Flutter Analyzer (SWFA) Installation Instructions
This AP Basic macro reads or sets the 2700 series instrument EEPROM firmware configuration to indicate the currently installed pre-analyzer filter. If you install or remove pre-analyzer filter hardware, you must set the EEPROM configuration for correct software operation. Requires AP2700 or APWIN version 2.24 or later control software.
These files accompany the "AP Basic Scripting" training video found at http://ap.com/support/training
The Audio Precision Resources Disc contains Sample Tests, the Performance Check and documentation to help you operate your AP2700 or ATS control software compatible audio analyzer. AP2700 or ATS control software is required. The installer includes both AP2700 and ATS-2 resources. You will be prompted to choose which components you wish to install.
This measurement looks at the four segments of an envelope expressed as amplitude vs. time; Attack, time for a signal to reach full amplitude, Decay, time for the signal to drop from the initial attack level to the sustain level, Sustain, time the signal remains at the constant amplitude, and Release, time for the signal to return to an off or zero amplitude condition.
Example utilizing C# for AP2700 "using references" (Visual C# 2005).
Measures and graphs the damping factor and output impedance vs. frequency of a power amplifier.
Accompanies KB article "Open Loop Crosstalk vs. Frequency."
AP2700 macro and test file to accompany the KB article "FFT Scaling for Noise."
Contains several functions that are useful for performing calculations on FFT spectra, including FFT spectrum integration with window correction. There is also a subroutine that will convert a measured FFT spectrum to amplitude spectral density in dB relative to 1.0 V/√Hz, or FS/√Hz, and plot it on the graph.
This AP2700 test file accompanies the KB article "Syncing the 2700 Series Generator to an External Reference."
GraphBuilder is a macro that extends the two-dimensional graph capability built into AP2700 and ATS control software to include three dimensional and polar graphs. For use with APWIN, download the previous version (1.1).
Tests PSRR (power supply rejection ratio). See the associated KB article for instructions. Contains .at27 test and .ads sweep file.
This AP Basic macro demonstrates the use of a modified AP.Prompt for use in control loops. It allows the AP.Prompt text to be changed while a prompt is displayed without flashing or refreshing the entire prompt window.
Many devices contain internal clocks that are not accessible but that need to be measured. Examples include the A/D converters in USB headsets, and the D/A converters in MP3 players and smart phones. The internal sample rate error of these types of devices can be indirectly determined by measuring the frequency error of a known tone. This download contains two AP2700 macros that calculate the error. See the associated KB article for instructions.
Macro and test file demonstrate how to send a bar graph reading to an RS-232 serial port.
Lets you set the graph trace properties quickly (line color, thickness, pattern, comments), even if you aren’t otherwise using macros or automation, by adding this macro to your Quick Launch toolbar.
Zip file includes macros for AP2700 and ATS, and Quick Launch installation instructions.
The ATS-2 and 2700 Series GPIB implementation requires that waveforms loaded into the analog and digital Arbitrary waveform buffers be mono files. Many of the sample waveforms provided for the two instruments are Stereo. This download contains two macros, one for each instrument, that can be used to split the stereo waveform into mono files.
Set of MATLAB functions for audio applications such as reading and writing waveforms and filters for 2700, ATS-2, and APx
Macro (procedure) for translating System One DOS files into APWIN files. Complete instructions for use are in the knowledge base article "Translating System One Files into APWIN, AP2700, or ATS."
System One Training Quicktime Video. Requires Quicktime player.
System One Training Quicktime Video. Requires Quicktime player.
System One Training Quicktime Video. Requires Quicktime player.
System One Training Quicktime Video. Requires Quicktime player.
System One Training Quicktime Video. Requires Quicktime player.
System One Training Quicktime Video. Requires Quicktime player.
System One training video. Requires Quicktime
S1 training video. Requires quicktime
System One Training Video
System One Training videos
System Two Family Performance Check for all System Two and 2700 Series instruments. Running the Performance Check verifies proper instrument operation, and provides diagnostic data for Technical Support evaluation before sending an instrument in for service.
Characterizing professional and consumer audio equipment requires techniques which often differ from those used to characterize other types of equipment. Sometimes this is due to the higher performance requirements. Other times it is due to the peculiarities of the audio industry. Other fields deal with some of the same measurements as those in audio. From level and THD to jitter and noise modulation, no other field has the breadth of requirements found in high performance audio.
This book by the late Julian Dunn examines in great detail techniques for evaluating the performance of converters and digital interfaces.
Includes a full set of AP2700 macros and tests that accompany the text.
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.
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
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.
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