Useful AES Standards
The Audio Engineering Society (AES) is a professional organization that publishes standards relevant to the audio industry. Below is a list of the ones I've found personally relevant. Access is free if you are an AES member.
AES3
AES standard for digital audio engineering - Serial transmission format for two-channel linearly represented digital audio data
AES3 provides for the serial digital transmission of two channels of periodically sampled and uniformly quantized audio signals on various media. This revision comprises four parts - also available separately - and includes all amendments prior to 2009.
Part 1 specifies the semantics of the audio data, including the "validity" flag. It also specifies the sampling frequency by reference to AES5, AES recommended practice for professional digital audio - Preferred sampling frequencies for applications employing pulse-code modulation.
Part 2 specifies the information transmitted with the audio data: principally the "channel status" but also user data and the use of the auxiliary bits to carry a co-ordination signal.
Part 3 specifies the framing and channel coding for transmission on a unidirectional point-to-point physical link. The specified format minimizes the direct-current (DC) component on the transmission line, facilitates clock recovery from the data stream, and makes the interface insensitive to the polarity of connections.
Part 4 specifies the physical signals that convey the bit stream specified in Part 3. The current version covers electrical signals on twisted-pair and co-axial cables. Other media, including fibre optic, are under consideration.
AES-2id
AES information document for digital audio engineering — 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 equipment in studio operations, and AES18, AES Recommended Practice for Digital Audio Engineering - Format for the user data channel of the AES digital audio interface.
AES14
AES standard for professional audio equipment - Application of connectors, part 1, XLR-type polarity and gender
This Audio Engineering Society (AES) standard specifies a common scheme for wiring the connectors used in audio systems, particularly to avoid the inversion of absolute polarity among the items in the analog signal chain.
AES68
AES standard for audio connectors - XL Connectors to Improve Electromagnetic Compatibility
This standard specifies a variant of the standard XLR connector that provides improved shell-to-shell connection to aid the rejection of RF interference. While maintaining compatibility with existing XLR connectors, a circumferential connection between the connector shells is added.
AES62
AES standard for audio connectors - Modified XLR-3 Connector for Digital Audio
This standard covers new connector types in order to identify AES3 equipment, signals and transmission circuits (tie lines). By extension, the same connectors will also identify AES42 microphone connections. The new "digital" connectors are based on the conventional analogue three pole XLR-type connectors with the difference of additional keying. The keying is realized in a manner as to prevent mating with conventional XLR-type connectors. Furthermore new "compatible" connectors that mate with both "digital" and conventional types are being specified.
AES72
AES standard on interconnections - Application of RJ45-type connectors and quad twisted pair cable for audio interconnections
This standard documents 8P8C (RJ45) pin-outs commonly used in analog and digital professional audio applications to carry four links, including channel/link order, signal polarity and phantom power compatibility. Type numbers are assigned to these variations, allowing manufacturers to easily specify which wiring standard is used in a particular piece of equipment. Users may use these type numbers to assess compatibility of disparate equipment in a given application. This standard also documents practical application details of interest to users of this technology. Conformance with this standard will identify mutually compatible devices, enabling users to avoid problems when employing equipment from multiple manufacturers.
AES59
AES standard for professional audio - Audio application of 25-way D-type connectors in balanced circuits
This document describes a standard contact assignment and gender convention for users of the 25-contact D-type connector as a multi-channel balanced audio interconnection, in analogue or AES3 digital form, to facilitate interconnection of equipment from different suppliers using standardized cables. The intent is to simplify the rapid and reliable interconnection of equipment in temporary installations, perhaps using rented equipment, although the method may be extended to permanent installations where appropriate.
AES20
AES recommended practice for professional audio - Subjective evaluation of loudspeakers
This Standard is a set of recommendations for subjective evaluation of high-performance loudspeaker systems. It is believed that, for certain audio components including loudspeakers, subjective 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.
AES75
AES standard for acoustics — Measuring loudspeaker maximum linear sound levels using noise
This standard details a procedure for measuring maximum linear sound levels of a loudspeaker system or driver using a test signal called Music-Noise. In order to measure maximum linear sound levels meaningfully and repeatably, a signal is required whose RMS and peak levels as functions of frequency have been shown to be representative of program material. Various existing standards define noise-based test signals which, like Music-Noise, have incorporated the knowledge that typical program material has a diminishing RMS level with increasing frequency, but Music-Noise uniquely also features a relatively constant peak level as a function of frequency, so that the crest factor (peak level – RMS level) increases with frequency, which an analysis on a large variety of music and other content has revealed is an important additional characteristic of typical program material. The specified procedure determines a loudspeaker’s maximum linear sound levels by incrementally increasing the Playback Level of Music-Noise until a stop condition is met: either an unacceptable change in the transfer function’s magnitude or an unacceptable change in the coherence of the transfer function.
AES26
AES recommended practice for professional audio — Conservation of the polarity of audio signals
This document standardizes the polarity of the signals at the various interface points between different items of equipment, in particular from the acoustical, electrical, mechanical, digital, and magnetic aspects. Each item of equipment complies separately with the polarity requirements for the input and output signals.
AES54
AES standard on interconnections - Grounding and EMC practices
This standard has three parts:
- 1: Connection of cable shields within connectors attached to portable balanced audio cables
This standard specifies requirements for, and summarizes general considerations relative to, the connection of cable shields within connectors attached to portable balanced cables for the transmission of audio, taking into account measures commonly necessary for the preservation of electromagnetic compatibility (EMC) at both audio and radio frequencies. (link) - 2: Shields of balanced audio wiring within fixed and portable passive connector panels,jack fields, and passive microphone splitters
This standard specifies requirements for, and summarizes general considerations relative to, the shielding of balanced audio interconnections within fixed and portable connector panels, jack fields (patch bays), and passive microphone splitters, taking into account measures commonly necessary for the preservation of electromagnetic compatibility (EMC) at both audio and radio frequencies. (link) - 3: Shields of balanced microphone-level outputs of active equipment other than microphones
This standard specifies requirements for, and summarizes general considerations relative to, the shielding of balanced microphone-level outputs of audio equipment, taking into account measures commonly necessary for the preservation of electromagnetic compatibility (EMC) at both audio and radio frequencies. (link)
AES-12id
AES Information Document for digital audio measurements - Jitter performance specifications
The question of sample-clock quality is a perennial one for digital audio equipment designers, yet most chip makers provide very little information about the jitter performance of their products. Consequently, equipment designers are sometimes caught out by jitter issues. The increasing use of packet-based communications and class-D amplification is throwing these matters into sharper relief.
This information document reviews various ways of characterizing and quantifying jitter, and refines several of them for audio purposes. It also attempts to present a common, unambiguous terminology. Its focus includes wideband jitter, baseband jitter, jitter spectra, period jitter, long-term jitter and jitter signatures. Comments are made on jitter transfer through phase-locked loops and on the jitter susceptibility of audio converters.
AES-R2
AES project report for articles on professional audio and for equipment specifications — Notations for expressing levels
This document describes the style for levels standardized in IEC 60027-3, Letter symbols to be used in electrical technology -- Part 3: Logarithmic Quantities and Units, and the power and voltage level clauses of IEC 60268-2 Sound system equipment -- Part 2: Explanation of general terms and calculation methods, and summarizes and reviews the presently-used notations for expressing levels in condensed or abbreviated form, what expressions are used, and what quantities and reference quantities are implied. The original document of 1998 was revised 2004-02 to delete considering the adoption of 1 V as the reference quantity for new work in audio engineering.