AES Standards News Blog

AES53-2006 (r2011) AES standard for digital audio — Digital input-output interfacing — Sample-accurate timing in AES47 has been reaffirmed.

This document specifies how the timing markers specified in AES47 may be used to associate an absolute timestamp with individual audio samples.  AES47 specifies a format for the transmission of digital audio over asynchronous transfer mode (ATM) networks.  A recommendation is made to refer these timestamps to the SMPTE epoch which in turn provides a reference to UTC and GPS time.

 AES52-2006 (r2011) AES standard for digital audio engineering — Insertion of unique identifiers into the AES3 transport stream has been reaffirmed.

The AES3 transport stream continues to be used extensively in both discrete and network based audio systems alongside audio stored as files. Audio content is moving towards being handled by asset management systems and descriptive metadata associated with that content is also being stored within systems. In order to provide a mechanism for AES3 transport streams to have similar abilities to work with content management systems, some form of unique label is required which can provide the link with these systems. One of the unique labels currently standardised in the media industry is the SMPTE UMID while another commonly used in the Information Technology area is the IEC UUID.

This standard specifies the method for inserting unique identifiers into the user data area of an AES3 stream. This specifically covers the use of UUID as well as a basic or extended SMPTE UMID.

AES51-2006 (r2011) AES standard for digital audio – Digital input-output interfacing – Transmission of ATM cells over Ethernet physical layer has been reaffirmed

This standard specifies a method, also known as “ATM-E”, of carrying asynchronous transfer mode (ATM) cells over hardware specified for IEEE 802.3 (Ethernet). It is intended as a companion standard to AES47 (Transmission of digital audio over ATM networks), to provide a standard method of carrying ATM cells and real-time clock over hardware specified for Ethernet.  

AES47-2006 (r2011), AES standard for digital audio - Digital input-output interfacing - Transmission of digital audio over asynchronous transfer mode (ATM) networks, has  been reaffirmed. 

This document specifies the method of carrying multiple channels of audio in linear PCM or AES3 format in calls across an asynchronous transfer mode (ATM) network to ensure interoperability. The specification includes the method of conveying information concerning the format and sampling frequency of the digital audio signal when setting up the calls.

 AES31-1-2001 (r2011), AES standard for network and file transfer of audio - Audio-file transfer and exchange - Part 1: Disk format has been reaffirmed.

This document defines a disk format specification to maintain compatibility with as wide a user base as possible to facilitate audio-file transfer and exchange between differing systems. The document does not describe a complete disk format but provides enough information for choosing a proprietary system that will maintain compatibility.

AES62-2011 AES standard for audio connectors - Modified XLR-3 Connector for Digital Audio has been published.

http://www.aes.org/publications/standards/search.cfm?docID=86

This new 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 specified. 

This standard specifies variants of the XLR connector family to be used for professional audio applications that include AES3 digital audio interfaces.

Test methods to confirm the correct function of the keying are indicated. Additional means supporting identification of different connector types are under consideration. 

The document does not include any electrical requirements.

AES-6id-2006 (r2011) AES information document for digital audio - Personal computer audio quality measurements has been reaffirmed in a new printing.

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-12id (r2011) AES Information Document for digital audio measurements - Jitter performance specifications has been reaffirmed in a new printing.

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. 

AES26-2001 (r2011) AES recommended practice for professional audio interconnections — Conservation of the polarity of audio signals has been reaffirmed in a new printing.

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.

 AES45-2001 (r2011) AES standard for single programme connectors — Connectors for loudspeaker-level patch panels has been reaffirmed in a new printing.

This standard complements IEC 60268-12 including amendments 1 and 2, extending the standardization of the application of AES45-series connectors to their use for loudspeaker-level patch panels.