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.
Resources & Utilities
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 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
APWIN Basic Extensions for System One v2.0
APWIN Basic Extensions for System One
AP Basic Language Manual v4 (View previous versions)
AP Basic Language Manual (previous versions titled: APWIN Basic User's Guide and Language Reference)
APWIN Simplified for System One v2.0 Rev 0
APWIN Simplified for System One
APWIN User's Manual Addendum v2.22 Rev 0
APWIN User's Manual Addendum for version 2.22
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
TechNotes/AppNotes
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.
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 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
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Datasheets
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Sample files
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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
Translated Material
Measuring Switch-mode Power Amplifiers - Japanese
Measuring Switch-mode Power Amplifiers - Japanese
System One & System Two - Japanese - Manual
System One & System Two - Japanese - Manual
