Discontinued Models DownloadsHOME/DOWNLOADS/DISCONTINUED MODELS
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 available from Audio Precision . 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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Software
APWIN Control Software v2.24 (View previous versions)
APWIN Control software. For all System One and System Two models.
AP2700 Control Software v3.30 (View previous versions)
AP2700 Control Software Compatible with all 2700 Series (2702, 2712, 2720, 2722)
Momentum DSP Filter Design Package
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.
AP2700 "DspRiff4.ocx " update v3.3x
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 replacement.
Resources & Utilities
Graph Builder for APWIN v1.1
GraphBuilder is an APWIN application that extends the two-dimensional graph capability built in to APWIN to three dimensions and polar graphs. GraphBuilder is actually an APWIN procedure that incorporates a graph building engine that will use data created by APWIN to produce graphs. It communicates with APWIN via OLE commands to offer a seamless operation with APWIN.
Matlab Toolbox v3.5 (View previous versions)
Set of MATLAB functions for audio applications such as generating arbitrary waveforms and filters for 2700 and ATS-2
2700 Series Windows APIB Drivers v1.0
Audio Precision's proprietary APIB interface bus requires the installation of the proper Windows driver software on your PC.
System Two Family Performance Check v1.21
System Two Family Performance Check macro for all System Two and 2700 Series instruments.
AP2700 & ATS-2 Resources Disc
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.
AES17 filter set bit macro
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.
System One Service Manual v1
System One Service Manual
System One DOS Translator Macro v1.1
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."
User Manuals
DCX-127 Multifunction Module User Manual vN/A
DCX-127 Multifunction Module User Manual
Errata for System Two Cascade Plus Specifications: FFT Acquisition Length v2.2 Rev 0
System Two Installation & Getting Started Manual v2.0 Rev 3
System Two Installation & Getting Started Manual
System Two Cascade Plus Installation & Getting Started Manual v2.2 Rev 0
System Two Cascade Plus Installation & Getting Started Manual
APWIN User's Manual for System Two Cascade v2.0 Rev1
APWIN User's Manual for System Two Cascade
APWIN User's Manual Addendum v2.22 Rev 0
APWIN User's Manual Addendum for version 2.22
APWIN User's Manual for System Two v2.0 Rev 0
APWIN User's Manual for System Two
APWIN Simplified for System Two Cascade v2.0
APWIN Simplified for System Two Cascade
AP Basic Language Manual v4 (View previous versions)
AP Basic Language Manual (previous versions titled: APWIN Basic User's Guide and Language Reference)
APWIN Basic Extensions for System Two Cascade v2.0
APWIN Basic Extensions for System Two Cascade
APWIN Basic Extensions for System Two v2.0
APWIN Basic Extensions for System Two
SIA-2322 Serial Interface Adapter User Manual v5.0
SIA-2322 Serial Interface Adapter User Manual
SWR-2122 Series Switchers User Manual v2.0
SWR-2122 Series Switchers User Manual
System Two Optional Filter Installation Guide v1
System Two Optional Filter Installation Guide
User-built Weighting Filter Construction Guide vRev 4
User-built Weighting Filter Construction Guide
System Two External Filter Installation Guide v1
System Two External Filter Installation Guide
System Two GPIB Installation Manual v1.0
System Two GPIB Installation Manual
System Two GPIB Programmer's Reference Manual v2.002 Rev 3
System Two GPIB Programmer's Reference Manual
Filter Design Package for System Two Cascade User Manual v1.1
Filter Design Package for System Two Cascade User Manual
System Two Rackmounting Instructions
System Two Rackmounting Instructions
System Two Burst Generator (SBUR) Installation Instructions
System Two Burst Generator (SBUR) Installation Instructions
System Two Intermodulation Generator (SIMG) Installation Instructions
System Two Intermodulation Generator (SIMG) Installation Instructions
System Two Intermodulation Analyzer (SIMA) Installation Instructions
System Two Intermodulation Analyzer (SIMA) Installation Instructions
System Two Wow & Flutter Analyzer (SWFA) Installation Instructions
System Two Wow & Flutter Analyzer (SWFA) Installation Instructions
GraphBuilder User's Manual v1.1
GraphBuilder User's Manual
APWIN Basic Extensions for System One v2.0
APWIN Basic Extensions for System One
APWIN Simplified for System One v2.0 Rev 0
APWIN Simplified for System One
APWIN User's Manual for System One v2.0 Rev 1
APWIN User's Manual for System One
System One GPIB Programmer's Reference Manual v2.10a
System One GPIB Programmer's Reference Manual
System One Installation & Getting Started Manual v2.0 Rev 3
System One Installation & Getting Started Manual
System Two Cascade Installation & Getting Started Manual v2.0 Rev 5
System Two Cascade Installation & Getting Started Manual
System Two Family Filter Installation Instructions
System Two Family Filter Installation Instructions
DCX User manual v1
TechNotes/AppNotes
Technote 28: Measurement Microphone dBspl Calibration
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.
Technote 10: SWR-122 Series Switchers APIB Interface Description
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.
Technote 15: GPIB Communication from AP Basic
This Technote describes how to setup communication between AP Basic and GPIB instrumentation (using the National Instruments GPIB Interface.)
Technote 17: Computing THD Measurements from FFT Data Using THD.exe
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.
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.
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 102: Using Audio Precision High Speed Tester (HST) v2.01
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.
Legacy Material
Appnote 1: CD & DVD Player Tests using System One or System Two vN/A
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.
Technote 1: Generating Impedance vs. Frequency Plots with System One
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.
Technote 1a: Generating Impedance vs. Frequency Plots with APWIN
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.
Technote 2: Generating Group Delay vs. Frequency Plots
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.
Technote 3: Remote Site Data Retrieval of Test Results Using Modems
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.
Technote 4: Computing Equalization Curves Using EQCURVE.EXE
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.
Technote 5: Usage Instructions for COMBINEC.EXE
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.
Technote 6: Computing Statistical Data From Nested Sweeps Using NSWEEP.exe
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.
Technote 8: Programmers' Reference to S1.exe DSP Waveform File Format
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.
Technote 9: Restructuring Multitrack Data Using MTRACKFR.exe
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
Technote 11: Remote Test Data Retrieval: Send a FAX
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.
Technote 12: Creating Arbitrary Waveforms Using Time Record data
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.
Technote 13: PC Sound Card Testing Using DSP-RIFF.exe Waveform Conversion Utility
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.
Technote 14: Testing Reduced Bit-Rate Codecs Using the System One DSP Program CODEC.dsp
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.
Technote 18: Multitone Waveform Creation Utility for Use with FASTTEST v1
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.
Technote 30: .WAV file Import
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.
Books
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.
Whitepapers
Measuring Switch-mode Power Amplifiers vN/A
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.
Limitations in making audio bandwidth measurements in the presence of out of band noise vN/A
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
Testing Challenges in Personal Computer Audio Devices vN/A
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
Measuring Digital Audio vN/A
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.
Fundamentals of Modern Audio Measurement vN/A
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.
Datasheets
High Speed Test in Production & Broadcast v3.1
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.
Sample Files
No files in this category
Service & Support
System One Training Vol 2: Interface card installation v1
System One Training Vol 7: Sweep Testing v1
System One Training Video
System One Training Vol 8: Saving Test Setups v1
System One Training Vol 9: Testing 2 channel devices v1
System One Training videos
System One Training Vol 10: Measuring Amplitude on two channels v1
System One Training Quicktime Video. Requires Quicktime player.
System One Training Vol 11: Analog Bargraph Displays v1
System One Training Quicktime Video. Requires Quicktime player.
System One Training Vol 12: Crosstalk measurements v1
System One Training Quicktime Video. Requires Quicktime player.
System One Training Vol 13: Plotting one measured value against another v1
System One Training Quicktime Video. Requires Quicktime player.
System One Training Vol 1: Unpack and inventory v1
System One training video. Requires Quicktime
System One Training Vol 6: Analyzer Architecture v1
System One Training Vol 3: Software Installation v1
S1 training video. Requires quicktime
AP2700 v3.3 MLS Quick Launch macro fix v1
Resolves an error with the MLS Quick Launch macro in AP2700 v3.3. When the MLS Quick Launch icon is clicked, and then the sweep Go button is clicked, the following message is displayed: "Error 18020: Channel 1 De-emphasis overload detected" Unzip this file, and save the two resulting files in the "My Documents\Audio Precision\AP2700 3.30\Quick Launch" directory, replacing the ones currently there. This will fix the problem.
Translated Material
Measuring Switch-mode Power Amplifiers (Japanese) v0
Measuring Switch-mode Power Amplifiers - Japanese
System One & System Two - Japanese - Manual
System One & System Two - Japanese - Manual
2700 Series Getting Started Guide (Korean) v1
2700 Series Getting Started Guide (Korean) Translated into Korean by AP Partner B&P International
AUX-0025 Datasheet (Chinese) v0
