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Audio Production System Standards 10-9

become the province of SMPTE standardization efforts. An index of the work of the engineering
committees is published yearly. The basic SMPTE documents issued as a part of the organiza-
tion’s standardization efforts are:

•

Engineering Guidelines—guidelines for the implementation of test materials and equipment
operation.

•

Recommended Practices—these include specifications for test materials, generic equipment
setup and operating techniques, and mechanical dimensions involving operational proce-
dures.

•

Standards—mechanical specifications for film, tape, cassettes, and transport mechanisms;
electrical recording and reproduction characteristics; and protocol and software issues for
digital video systems.

Audio Engineering Society

The AES (www.aes.org) was organized in 1948 primarily to serve the needs of the high quality
audio recording and reproduction community. The Society maintains a standards committee
(AESSC) that supervises the work of subcommittees and working groups. Drafts of proposed
standards are published in the Journal of the Audio Engineering Society (JAES) for review and
comment by all interested parties. Any substantive comments (as opposed to editorial) are then
considered by the committee before submitting the final document to a vote. Current AES stan-
dards address measurement methods, commercial loudspeaker specifications, and digital audio
recording/transmission systems.

10.1.3 AES Documents

The following documents relating to audio technologies in general, and digital audio in particu-
lar, are available from the Audio Engineering Society. For more information, contact the AES at
www.aes.org.

10.1.3a

Informational Documents

AES-2id-1996 (r2001)

: Guidelines for the Use of the AES3 Interface

This document provides guidelines for the use of AES3, AES Recommended Practice for Digital
Audio Engineering—Serial transmission format for two-channel linearly represented digital
audio data, together with AES5, AES Recommended Practice For professional digital audio
applications employing pulse-code modulation—Preferred sampling frequencies, AES11, AES
Recommended Practice for Digital Audio Engineering—Synchronization of digital audio equip-
ment in studio operations, and AES18, AES Recommended Practice for Digital Audio Engineer-
ing—Format for the user data channel of the AES digital audio interface.

AES-3id-2001 (Revision of AES-3id-1995): 

Transmission of AES3 Formatted Data by

Unbalanced Coaxial Cable

This document contains information regarding cables, cable equalizers, and receiver circuits
including adaptors to or from standard AES3 equipment and cabling where it is required to trans-

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Audio Production System Standards

10-10 Audio Production Standards, Equipment, and System Design

mit AES3 formatted signals over long distances (up to 1000 m), or in a video installation using
analog video distribution equipment. It is not intended to be an alternative electrical specifica-
tion to AES3, which is based on balanced, shielded, twisted-pair cable transmission over dis-
tances of up to 100 m. The information is based on studies and laboratory experiments discussed
in a series of technical reports that have been partly summarized and included.

AES-4id-2001

: Characterization and Measurement of Surface Scattering Uniformity

This document provides guidelines for characterizing the uniformity of scattering produced by
surfaces from measurements or predictions of scattered polar responses. In this context, the sur-
face scattering is quantified in terms of a single diffusion coefficient. The diffusion coefficient is
a measure of quality designed to be used by producers and users of surfaces that, either deliber-
ately or accidentally, diffuse sound. It is also intended for use when needed by developers and
users of geometric room acoustic models. The diffusion coefficient is not intended, however, to
be blindly used as an input to current diffusion algorithms in geometric room acoustic models.
The diffusion coefficient characterizes the sound reflected from a surface in terms of the unifor-
mity of the scattered polar distribution. The information document details a free-field character-
ization method.

AES-5id-1997:

 Loudspeaker Modeling and Measurement—Frequency and Angular

Resolution for Measuring, Presenting, and Predicting Loudspeaker Polar Data

This document provides guidelines for measuring, presenting and predicting polar data from a
single acoustic source or from an array of acoustic sources. It describes and quantifies measure-
ment resolution, presentation resolution, prediction techniques and measurement environments.
The information presented here is based on objective measurements and does not take subjective
or psychoacoustic criteria into account.

AES-6id-2000

: Personal Computer Audio Quality Measurements

This document focuses on the measurement of audio quality specifications in a PC environment.
Each specification listed has a definition and an example measurement technique. Also included
is a detailed description of example test setups to measure each specification.

AES-10id-1995

: Engineering Guidelines for the Multichannel-Audio Digital Interface

(MADI) AES10

This document provides guidance for areas of application of the MADI standard (AES10) that
might be unclear. It is not intended to replace AES10, but to supplement it in those areas that are
not suitable for definition in a standards document.

10.1.3b

Project Reports

AES-R1-1997:

 Specifications for Audio on High-Capacity Media

This document is the report of Task group SC-02-M, a task force within the Audio Engineering
Society Standards Committee (AESSC), which studied the future of high-capacity audio media
(such as DVD) for over one year with input from more than 80 persons and organizations.

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Audio Production System Standards

Audio Production System Standards 10-11

AES-R3-2001

: Compatibility for Patch Panels of Tip-Ring-Sleeve Connectors

This report covers the concentric connectors known as phone plugs and jacks that are widely
used in the audio industry for the interconnection of sound system components as general-use
consumer tip-ring-sleeve (TRS) types as well as for the interconnection of broadcast and other
professional systems, such as professional TRS types. Because differing dimensions specified by
various standards often result in mechanical and, as a consequence, electrical incompatibilities
among the various TRS jacks and plugs, this report surveys the standards, connectors, and possi-
ble incompatibility problems.

10.1.3c

Standards and Recommended Practices

AES2-1984 r1997

: Specification of Loudspeaker Components used in Professional

Audio and Sound Reinforcement

This document is a recommended practice for describing and specifying loudspeaker compo-
nents used in professional audio and sound-reinforcement systems. These components include
high-frequency drivers, high- and mid- frequency horns, low-frequency drivers, and low-fre-
quency enclosures. For drivers, specifications are given for describing frequency response,
impedance, distortion, and power handling. For horns and enclosures, specifications are given
for describing directional characteristics and additional pertinent performance data. For all com-
ponents, specifications as are given for describing necessary physical and mechanical character-
istics, such as hardware, mounting data, size, and weight. Appendices supporting the text give
guidelines for making proper free-field measurements, sizing of baffles for low-frequency mea-
surements, a method for producing the specified noise signal used in power testing, and a sum-
mary of required information.

AES3-1992 (r1997):

 Serial Transmission Format for Two-Channel Linearly Represented

Digital Audio Data

The format provides for the serial digital transmission of two channels of periodically sampled
and uniformly quantized audio signals on a single shielded twisted wire pair. The transmission
rate is such that samples of audio data, one from each channel, are transmitted in time division
multiplex in one sample period. Provision is made for the transmission of both user and interface
related data as well as of timing related data, which may be used for editing and other purposes.
It is expected that the format will be used to convey audio data that have been sampled at any of
the sampling frequencies recognized by the AES5, Recommended Practice for Professional Dig-
ital Audio Applications Employing Pulse-Code Modulation—Preferred Sampling Frequencies.

AES5-1998:

 Preferred Sampling Frequencies for Applications Employing Pulse-Code

Modulation

A sampling frequency of 48 kHz is recommended for the origination, processing, and inter-
change of audio programs employing pulse-code modulation. Recognition is also given to the
use of a 44.1-kHz sampling frequency related to certain consumer digital applications, the use of
a 32-kHz sampling frequency for transmission-related applications, and the use of a 96-kHz
sampling frequency for applications requiring a higher bandwidth or more relaxed anti-alias fil-
tering.

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Audio Production System Standards

10-12 Audio Production Standards, Equipment, and System Design

AES6-1982 r1997:

 Method for Measurement of Weighted Peak Flutter of Sound

Recording and Reproducing Equipment

Weighted peak flutter is measured using a 3150-Hz tone transmitted through the equipment. The
tone is frequency demodulated, frequency-response weighted, peak-to-peak detected, time-
response weighted, and read on a meter as the zero-to-peak (one-half of peak-to-peak) values.
Results are reported as “weighted peak of the recorder (or reproducer, or recording/reproducing
system): +/- __ percent.” A toleranced graph and table give the frequency-response weighting
(approximately a 6-dB-per-octave drop above and below 4 Hz, with an additional drop below 0.5
Hz.) A toleranced table gives the time-response weighting (the reference is the peak-to-peak
amplitude of a 4-Hz sine wave; the test signal is a series of unidirectional pulses of the same
peak-to-peak amplitude, spaced 1 second apart; a pulse length of 60 ms gives 90-percent
response; the fall between 100-ms pulses is a 40-percent reading.)

Good engineering practices are given for the meter design. The rationale for this standards is

given in an appendix. This standard, originally published as IEEE Std-193, has technical require-
ments identical to standards IEC Pub. 386, CCIR 409-2, and DIN 45 507. An ANSI version is
available as S4.3-1982.

AES7-2000:

 Method of Measuring Recorded Fluxivity of Magnetic Sound Records at

Medium Wavelengths

This standard specifies a method of measuring the recorded flux per unit track width, called flux-
ivity, of a magnetically recorded sinusoidal test signal at medium wavelengths for all magnetic
sound record formats, by using a high-efficiency magnetic reproducing head. It also specifies the
equipment needed to implement this method. An ANSI version is available as S4.6-1982.

AES10-1991 (r1997):

 Serial Multichannel Audio Digital Interface (MADI) 

This standard describes the data organization for a multi-channel-audio digital interface. It
includes a bit level description, features in common with the AES3-1985 two channel format,
and the data rates required for its utilization. The specification provides for the serial digital
transmission of 56 channels of linearly represented digital audio data at a common sampling fre-
quency within the range 32 kHz to 48 kHz (+/- 12.5%) having a resolution of up to 24 bits per
channel. 

The format makes possible the transmission and reception of the complete 28-bit channel

word (excluding preamble) as specified in the document AES3-1985, providing for the validity,
user, channel status, and parity information allowable under that Standard. The transmission for-
mat is of the asynchronous simplex type and is specified for a single 75 ohm coaxial cable point-
to-point interconnection, although the use of fibre-optic medium is also possible. An ANSI ver-
sion is available as S4.43-1991.

AES11-1997

: Synchronization of Digital Audio Equipment in Studio Operations

This standard provides a systematic approach to the synchronization of digital audio signals.
Recommendations are made concerning the accuracy of sample clocks as embodied in the inter-
face signal and the use of this format as a convenient synchronization reference where signals
must be rendered co-timed for digital processing. Synchronism is defined, and limits are given
which take account of relevant timing uncertainties encountered in an audio studio.

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Audio Production System Standards

Audio Production System Standards 10-13

AES14-1992 (r1998):

 Application of Connectors, Part 1—XLR-Type Polarity and Gen-

der

This standard specifies a common scheme for wiring the connectors used in audio systems, par-
ticularly to avoid the inversion of absolute polarity among the items in the analog signal chain.
An ANSI version is available as S4.48-1992.

AES15-1991 (r1997):

 Sound-Reinforcement Systems Communications Interface (PA-

422)

This standard specifies the electrical characteristics of a balanced-voltage circuit for the inter-
change of serial binary signals for the control of sound-reinforcement systems. It provides for
interchange among data terminal equipment (DTE), that is, computers and microprocessors, and
data circuit terminating equipment (DCE). PA-422 is a mnemonic, signifying professional audio
implementation of Electronics Industries Association EIA-422-A. Device control language is
provided in an annex. An ANSI version is available as S4.49-1991.

AES17-1998 (revision of AES17-1991)

: Measurement of Digital Audio Equipment

This standard provides methods for specifying and verifying the performance of digital audio
equipment. Many tests are substantially identical to those used when testing analog equipment.
However, because of the unique requirements of digital audio equipment and the effects of its
imperfections, additional tests are necessary.

AES18-1996 (revision of AES18-1992):

 Format for the User Data Channel of the AES

Digital Audio Interface

This standard describes a method of formatting the user data channels provided within the digital
audio serial interface format (AES3). The transmission format is an adaptation of the packet-
based high-level data link control (HDLC) communications protocol and provides for the trans-
mission of ancillary data that may or may not be time related to the audio signal. The data rate is
constant within a range of +/- 12.5 percent of a sampling frequency of 48 kHz. The standard also
provides a data priority and management strategy to ensure that adequate capacity is available for
downstream data insertion.

AES19-1992 r1998

: Measurement of the Lowest Resonance Frequency of Loud-

speaker Cones

This standard test method is intended to determine the frequency of lowest resonance of a loud-
speaker cone. Such information is used for engineering design and for quality control. The
method has been developed to improve correlation of measurement between cone manufacturers
and loudspeaker manufacturers. An ANSI version is available as S4.30-1992.

AES20-1996:

 Subjective Evaluation of Loudspeakers

This standard is a set of recommendations for subjective evaluation of high-performance loud-
speaker systems. It is believed that, for certain audio components including loudspeakers, sub-
jective evaluation is a necessary adjunct to objective measurements. The strong influence of
listening conditions, program material and of individual evaluators is recognized. This document
seeks, therefore, to assist in avoiding testing errors rather than to attempt to establish a correct
procedure.

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Audio Production System Standards