AES Standards Committee News

• AES11-2009 Synchronization of digital audio equipment
  

  AES11-2009, AES recommended practice for digital audio engineering - Synchronization of digital audio equipment in studio operations has been published, 2009-06-01.
  
  This revised 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 interface signal and the use of this format as a convenient synchronization reference where signals must be rendered cotimed for digital processing. Synchronism is defined, and limits are given which take account of relevant timing uncertainties encountered in an audio studio.
  
  In this revision, the relationship with AES5 has been clarified, with tolerances specified only in AES11 and nomenclature for multiple rates only in AES5. The subclause on video referencing (4.5) and Annex B (Word Clock) have been revised to more accurately reflect the current situation in the field. Annex D has been added.

• AES56-2008 Loudspeaker polar radiation measurements
  

  AES56-2008, AES standard on acoustics - Sound source modeling - Loudspeaker polar radiation measurements has been reprinted with addenda 2009-03-10.
  
  Addenda 2009-03-10: The notes to clause 4.2.3.1, 4.2.3.2, and 4.2.3.3 have been updated to clarify various practical cases.

• Call for comment on draft revised AES11-xxxx, Synchronization of digital audio equipment
  

  A call for comment on draft revised AES11-xxxx, AES recommended practice for digital audio engineering - Synchronization of digital audio equipment in studio operations, has been published 2009-02-23

• AES47-Am1-2008, Amendment 1 to AES47 - Transmission of digital audio over asynchronous transfer mode (ATM) networks has been published
  

  This Amendment adds code points in the ATM Adaptation Layer Parameters Information Element to signal that the time to which each audio sample relates can be identified as specified in AES53.

• AES31-2-Am1-2008, Amendment 1 to AES31-2 - Extended file format for audio to exceed 4 GByte has been published
  

  The 32-bit address space of a Wave file limits its maximum size to 4 GB. Some practical computer systems may impose a lower limit of 2 GB. This is not a significant obstacle for mono files at basic rate sampling frequencies, but the limitation becomes increasingly significant as the number of channels in the file is increased or when double- or quadruple-rate sampling frequencies are used. The Extended Broadcast Wave Format (BWF-E) file format described in this amendment is designed to be a compatible extension of the Broadcast Wave Format (BWF) already defined in AES31-2. It extends the maximum size capabilities of the RIFF/WAVE format by increasing its address space to 64 bits where necessary. BWF-E is also designed to be mutually compatible with the EBU T3306 "RF64" extended format.

• AES10-2008, Serial Multichannel Audio Digital Interface (MADI) has been published
  

  This standard describes the data organization for a multichannel audio digital interface. It includes a bit-level description, features in common with the AES3 two-channel format, and the data rates required for its utilization. The specification provides for the serial digital transmission of 32, 56, or 64 channels of linearly represented digital audio data at a common sampling frequency within the range 32 kHz to 96 kHz, 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 AES3, providing for the validity, user, channel status, and parity information allowable under that standard. The transmission format is of the asynchronous simplex type and is specified for a single 75-ohm coaxial cable point-to-point interconnection or the use of fibre-optic cables.
  
  This revision includes minor changes to conform to recent revisions of AES3 and AES5 and provides clarifications of sync reference signals and link transmission-rate tolerance, and references for 'NRZI' and the 4B5B coding scheme.

• AES6-2008, Method for measurement of weighted peak flutter of sound recording and reproducing equipment, a revision of AES6-1982, has been published
  

  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 out on a two-sigma statistical voltmeter over a period of at least 5 s. Results are reported as "weighted peak flutter of the recorder (or reproducer, or recording/reproducing system): ± __ percent."
  
  A toleranced graph and table give the frequency-response weighting (approximately at 6-dB-per-octave drop above and below 4 Hz, with an additional drop below 0,5 Hz). The statistical voltmeter is described; it is preferred, and replaces the quasi-peak meter (now deprecated) of the original standard.
  
  Good engineering practices are given for the meter design. The rationale for this standard is given in an annex. This standard has technical requirements identical to IEC 60386 Ed.1 1972 as amended by IEC 60386-am1, 1988. Measurement results according to this standard are identical to those made according to the older standards originally published as IEEE Std-193, IEC 60386 Ed.1 1972, CCIR 409-2, and DIN 45 507.

• AES22-1998 (r2008), Storage of polyester magnetic tape has been reaffirmed
  

  This standard provides recommendations concerning the storage conditions, storage facilities, enclosures, and inspection for recorded polyester-base magnetic tapes in roll form. It covers analog and digital tape and includes tape made for audio, video, instrumentation, and computer use.

• AES28-1998 (r2008), life expectancy of compact discs (CD-ROM) has been reaffirmed
  

  This standard specifies test methods for estimating the storage life expectancy (LE) of information stored on compact discs (CD-ROM). Only the effects of temperature and relative humidity are considered. Block error rate (BLER) is the measured response and the end-of-life criterion. An Eyring model is developed from accelerated test results. Data are normalized to 25 °C and 50 % relative humidity, and the LE, percent compliance, and confidence intervals at these conditions are calculated.

• AES56-2008 Loudspeaker polar radiation measurements
  

  A new document, AES56-2008, AES standard on acoustics - Sound source modeling - Loudspeaker polar radiation measurements has been published 2009-01-09.
  
  This standard describes how the measurements of loudspeaker polar radiation data shall be made and documented. This acquired data is suitable for application in room acoustic, electro-acoustic, and sound system predictions, and loudspeaker data sheets.

• AES54-1-2008 Connection of cable shields within connectors attached to portable balanced audio cables
  

  A new document, AES54-1-2008, AES standard on interconnections - Grounding and EMC practices - Connection of cable shields within connectors attached to portable balanced audio cables has been published 2009-01-09.
  
  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.

• AES54-2-2008 Shields of balanced audio wiring within fixed and portable passive connector panels, jack fields, and passive microphone splitters
  

  A new document, AES54-2-2008, AES standard on interconnections - Grounding and EMC practices - Shields of balanced audio wiring within fixed and portable passive connector panels, jack fields, and passive microphone splitters has been published 2009-01-09.
  
  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.

• AES54-3-2008 Shields of balanced microphone-level outputs of active equipment other than microphones
  

  A new document, AES54-3-2008, AES standard on interconnections - Grounding and EMC practices - Shields of balanced microphone-level outputs of active equipment other than microphones has been published 2009-01-09.
  
  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.

• Call for comment on draft amendment AES47-A1-xxxx, Amendment 1 to AES47
  

  A call for comment on draft amendment AES47-A1-xxxx, Amendment 1 to AES47 AES standard for digital audio - Digital input-output interfacing - Transmission of digital audio over asynchronous transfer mode (ATM) networks, has been published 2008-11-13

• Call for comment on draft amendment AES31-2-Am.1-xxxx, Extended file format for audio to exceed 4 GByte
  

  A call for comment on draft amendment AES31-2-Am.1-xxxx, Amendment 1 to AES31-2 - Audio-file transfer and exchange - Part 2: File Format for Transferring Digital Audio Data Between Systems of Different Type and Manufacture - Amendment 1: Extended file format for audio to exceed 4 GByte, has been published 2008-11-13

• Call for comment on draft revised AES10-xxxx, Multichannel Audio Digital Interface (MADI)
  

  A call for comment on draft revised AES10-xxxx, AES Recommended Practice for Digital Audio Engineering - Serial Multichannel Audio Digital Interface (MADI) , has been published 2008-11-13

• Call for comment on draft revised AES6-xxxx, Weighted Peak Flutter
  

  A call for comment on draft revised AES6-xxxx, AES Standard, Method for Measurement of Weighted Peak Flutter of Sound Recording and Reproducing Equipment, has been published 2008-11-13

• AES3-Am.6-2008 Amendment 6 to AES3-2003
  

  A new document, AES3-Am.6-2008 Amendment 6 to AES3, AES standard for digital audio engineering - Serial transmission format for two-channel linearly represented digital audio data has been published 2008-11-12.
  
  The "minimum" implementation of Channel Status was included in the original AES3 specification to allow implementers to reduce the complexity of transmitting interfaces. Its use has always been discouraged, and in the context of current electronics hardware the complexity saving compared to the Standard implementation is not significant. Moreover, it adds complexity to receivers by requiring them to recognize a special case which does not have a correct CRC in byte 23, and in practice many receivers do not recognize it and flag a CRC error.
  
  This Amendment withdraws the "minimum" implementation of Channel Status. Thus transmitters that use it will no longer conform to AES3, but the practice of insisting on a correct CRC in receivers now will conform.
  
  This Amendment also adds a code point to byte 1, bits 4 to 7, to support the carriage of MIDI data in the user bits as specified in IEC 62537 (digital interface for loudspeakers).

• AES5-2008 Preferred sampling frequencies
  

  A revised standard, AES5-2008 AES recommended practice for professional digital audio - Preferred sampling frequencies for applications employing pulse-code modulation has been published 2008-11-12.
  
  A sampling frequency of 48 kHz is recommended for the origination, processing, and interchange 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 audio 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 filtering.
  
  Further developments in working practices in digital audio have given rise to the use of even higher sampling frequencies and this revision quantifies the preferred choices for these practices. Matters of sampling-frequency precision have been removed from this standard to be handled more appropriately by the associated standard AES11 on Synchronization of digital audio equipment in studio operations.

• Call for comment on reaffirmation of AES22-1998 (r2003), Storage of polyester magnetic tape
  

  The Call for comment on reaffirmation of AES22-1997 (r2003), AES recommended practice for audio preservation and restoration - Storage of polyester-based magnetic tape, has been published, 2008-11-03

• Call for comment on reaffirmation of AES28-1998 (r2003), life expectancy of compact discs (CD-ROM)
  

  The Call for comment on reaffirmation of AES28-1997 (r2003), AES standard for audio preservation and restoration - Method for estimating life expectancy of compact discs (CD-ROM), based on effects of temperature and relative humidity, has been published, 2008-10-27

• AES58-2008, Application of IEC 61883-6 32-bit generic data
  

  AES58-2008, AES standard for digital audio - Audio applications of networks - Application of IEC 61883-6 32-bit generic data, has been published 2008-10-03
  
  The primary use of IEEE-1394 isochronous packets, as defined in IEC 61883-6, is for carrying audio and music data. This document defines an efficient means for carrying data in a wider variety of formats, for example professional audio and manufacturer-specific data, in IEC 61883-6 isochronous packets.

• Call for comment on draft AES54-1-xxxx, Connection of cable shields for portable balanced audio cables
  

  A call for comment on draft AES54-1-xxxx, AES standard on interconnections - Grounding and EMC practices - Connection of cable shields within connectors attached to portable balanced audio cables, has been published 2008-09-16

• Call for comment on draft AES54-2-xxxx, Shielding of wiring within passive connector panels and microphone splitters
  

  A call for comment on draft AES54-2-xxxx, AES standard on interconnections - Grounding and EMC practices - Shields of balanced audio wiring within fixed and portable passive connector panels, jack fields, and passive microphone splitters, has been published 2008-09-16

• Call for comment on draft AES54-3-xxxx, Shields of microphone-level outputs of active equipment
  

  A call for comment on draft AES54-3-xxxx, AES standard on interconnections - Grounding and EMC practices - Shields of microphone-level outputs of active equipment other than microphones, has been published 2008-09-16

• Call for comment on draft AES56-xxxx Loudspeaker polar radiation measurements
  

  A call for comment on draft AES56-xxxxAES standard on acoustics - Sound source modeling - Loudspeaker polar radiation measurements, has been published 2008-09-11
  
  This standard describes how the measurements of loudspeaker polar radiation data shall be made and documented. This acquired data is suitable for application in room acoustic, electro-acoustic, and sound system predictions, and loudspeaker data sheets.

• New Project, AES-X182 AES/Ethernet Simple Open Protocol
  

  A new project, AES-X182, AES/Ethernet Simple Open Protocol, has been initiated 2008-09-03 and assigned to the SC-02-02 working group on digital audio interfaces.
  
  The project is intended to produce a standard to specify a means for transmission over category 5 data cable of unidirectional digital audio and bidirectional control data. Intended applications are active loudspeakers and amplifiers for live performance and for installations

• AES-R10-2008 Use cases for networks in professional audio
  

  AES-R10-2008, AES standards project report - Use cases for networks in professional audio, has been published 2008-08-25.
  
  Use cases for some advanced audio applications using the IEEE 1394 Higher Performance Serial Bus were explored by joint task groups set up by AES Standards Working Group SC-02-12 and the 1394TA Pro Audio Working Group. The work was subdivided into three application areas; Recording, Live Sound, and Installations. This report summarises the output of these three groups.

• Call for comment on DRAFT AES3-am6-xxxx, Amendment 6 to AES3
  

  A Call for Comment on DRAFT AES3-Am6-xxxx, Amendment 6 to AES standard for digital audio - Digital input-output interfacing - Serial transmission format for two channel linearly represented digital audio data, was published 2008-08-11.

• Call for comment on DRAFT REVISED AES5-xxxx, Preferred sampling frequencies
  

  The Call for Comment on DRAFT REVISED AES5-xxxx, AES recommended practice for professional digital audio - Preferred sampling frequencies for applications employing pulse-code modulation, has been published 2008-08-10.

• Call for comment on DRAFT AES58-xxxx, Application of IEC 61883-6 32-bit generic data
  

  A Call for Comment on DRAFT AES58-xxxx, AES standard for digital audio - Audio applications of networks - Application of IEC 61883-6 32-bit generic data, has been published 2008-07-01.
  The comment period has now closed. There were no comments.

• AES31-3-2008, Simple project interchange
  

  AES31-3-2008, AES standard for network and file transfer of audio - Audio-file transfer and exchange - Part 3: Simple project interchange, has been published 2008-05-08.

  This standard provides a convention for expressing audio edit data in text form in a manner that enables simple and accurate computer parsing while retaining human readability. Edit precision is sample-accurate while a presentation method (TCF) retains the readability of conventional frame-based time codes.
  
  This revision incorporates previous corrigenda, and includes a number of editorial updates and corrections based on experiences of practical implementation. It has also been extended to include support for higher sampling frequencies and simple gain and surround pan automation.

• AES3-am5-2008, Amendment 5 to AES3-2003
  

  AES3-am5-2008, Amendment 5 to AES standard for digital audio - Digital input-output interfacing - Serial transmission format for two channel linearly represented digital audio data, has been published 2008-04-19.

  Recent projects to support carriage of MPEG Surround data in an AES3 bitstream (see AES55-2007), as well as questions arising when considering non-PCM data in an AES3 signal, require some detailed changes to the AES3 specification. This amendment adds a flag to indicate hidden data within a PCM signal, provides indications for two additional sampling frequencies, and clarifies the use of certain status bits when the signal is non-PCM.

• AES55-2007, Carriage of MPEG Surround in an AES3 bitstream
  

  AES55-2007, AES standard for digital audio engineering - Carriage of MPEG Surround in an AES3 bitstream, has been published 2008-03-18.

  MPEG Surround is an ISO/IEC standard to extend mono or stereo audio towards multiple channels. The mono or stereo audio channels represent a downmix of the original multi-channel audio that is generated by the MPEG Surround encoder. In addition the MPEG Surround encoder generates spatial side information (MPEG Surround data). An MPEG Surround decoder is able to combine this information with the downmix to result in a multichannel audio signal. In this way backward compatibility to mono and stereo systems is achieved.

  This standard specifies how MPEG Surround shall be carried within an AES3 bitstream where the downmix channels remain in the linear PCM domain and the MPEG Surround data is encoded into the least-significant bits of the PCM audio data.

• AES-R9-2008 Considerations for standardising AES metadata sets
  

  AES-R9-2008, AES standards project report - Considerations for standardising AES metadata sets, has been published 2008-03-12.
  
  This report discusses primary issues and outlines some elementary considerations relevant to the standardisation of sets of audio metadata.

• Call for comment on DRAFT REVISED AES31-3-xxxx, Simple project interchange
  

  A Call for Comment on DRAFT REVISED AES31-3-xxxx, AES standard for network and file transfer of audio - Audio-file transfer and exchange - Part 3: Simple project interchange, was published 2008-02-07.

• Call for comment on DRAFT AES3-am5-xxxx, Amendment 5 to AES3
  

  A Call for Comment on DRAFT AES3-Am5-xxxx, Amendment 5 to AES standard for digital audio - Digital input-output interfacing - Serial transmission format for two channel linearly represented digital audio data, published 2008-01-18, has closed without comment.

• Call for comment on DRAFT AES55-xxxx, Carriage of MPEG Surround in an AES3 bitstream
  

  A Call for Comment on DRAFT AES55-xxxx, AES standard for digital audio engineering - Carriage of MPEG Surround in an AES3 bitstream, published 2007-12-17, has closed without unresolved comment.

• AES-R8-2007 Synchronisation of digital audio over wide areas
  

  AES-R8-2007, AES standards project report - Synchronisation of digital audio over wide areas, has been published 2007-12-06.
  
  This document is intended to provide guidance on synchronisation issues to implementers of systems in which an audio signal originated in digital form in one location is transmitted over a digital network to another location.

• Call for comment on reaffirmation of AES46-2002, Radio traffic audio delivery extension to the broadcast-WAVE-file format
  

  The Call for Comment on reaffirmation of AES46-2002 AES standard for network and file transfer of audio Audio-file transfer and exchange Radio traffic audio delivery extension to the broadcast-WAVE-file format, published 2007-07-04, closed without unresolved comment. AES46-2002 (r2007) is reaffirmed.

• Call for comment on reaffirmation of AES20-1996 (r2002), Subjective evaluation of loudspeakers
  

  The Call for Comment on reaffirmation of AES20-1996 (r2002), AES recommended practice for professional audio - Subjective evaluation of loudspeakers, published 2007-11-15, has closed without comment. AES20-1996 (r2007) is reaffirmed.

• Call for comment on reaffirmation of AES27-1996 (r2002), Managing recorded audio materials intended for examination
  

  The Call for Comment on reaffirmation of AES27-1996 (r2002), AES recommended practice for forensic purposes - Managing recorded audio materials intended for examination, published 2007-10-31, has closed without comment. AES27-1996 (r2007) is reaffirmed.

• AES-R4 Guidelines for AES47 - Transmission of digital audio over (ATM) networks NEW REVISION
  

  AES-R4-2007, AES standards project report Guidelines for AES Recommended practice for digital audio engineering -- Transmission of digital audio over asynchronous transfer mode (ATM) networks, a revision of AES-R4-2002, has been published 2007-07-04.
  
  The report was revised to correspond to the 2006 edition of AES47 and to take account of other events such as the publication of AES51, AES52, and AES53.<.p>

• Call for comment on reaffirmation of AES46-2002, Radio traffic audio delivery extension to the broadcast-WAVE-file format
  

  The Call for Comment on reaffirmation of AES46-2002 AES standard for network and file transfer of audio Audio-file transfer and exchange Radio traffic audio delivery extension to the broadcast-WAVE-file format, published 2007-07-04, closed without unresolved comment. AES46-2002 (r2007) is reaffirmed.

• AES-2id-2006, Guidelines for the use of the AES3 interface has been published
  

  This document provides guidelines for the use of AES3, "Serial transmission format for two-channel linearly represented digital audio data", together with AES5, "Preferred sampling frequencies", and AES11, "Synchronization of digital audio equipment in studio operations".
  
  This extensive and substantial 2006 revision integrates all that information relating to standards AES3, AES5, AES11 and information document AES-3id that is important to the implementation of AES3 but which is itself not part of the standard in any normative sense.
  
  These guidelines are intended to assist a user to understand and use the AES3 digital audio interface. The examples provided are not intended to be restrictive, but to clarify. The AESSC hopes these guidelines will further the design of mutually compatible interfaces and encourage consistent operational practices. This revision includes details on the implementation of the coaxial interface described in AES-3id-2001.
  
  This text has been restructuring to split physical, transport and essence into separate parts which may be more conveniently revised in the future.
  [2007-04-06]

• AES-12id-2006, Jitter performance specifications has been published
  

  A new Information Document, AES-12id-2006, AES Information Document for digital audio measurements - Jitter performance specifications, has been published.
  
  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.
  [2007-03-19]

• AES-6id-2006, Personal computer audio quality measurements has been published
  

  A substantially updated Information Document, AES-6id-2006, AES information document for digital audio - Personal computer audio quality measurements, has been published.
  
  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.
  
  There have been many improvements in PC audio since the original AES-6id document was published. This revision of AES-6id-2000 includes substantial updates that reflect the improvements in the PC sound sub-system, as well as some updates based on many real world measurements.
  [2007-02-21]

• AES-11id-2006, Extended term storage environment for multiple media archives has been published
  

  A new Information Document, AES-11id-2006, Extended term storage environment for multiple media archives has been published
  
  This information document provides guidelines for archivists faced with storing a variety of audio, still image and moving image media in a single storage environment. This circumstance is faced by many archivists in small and medium size archives that must preserve and make available the wide variety of media from nitrate film to optical discs. These guidelines provide recommendations to harmonize storage recommendations contained in standards and recommended practices published by the AES and the International Standards Organization (ISO).
  [2007-02-19]

• Call for comment on reaffirmation of AES-4id-2001, Surface scattering uniformity
  

  The Call for comment on reaffirmation of AES-4id-2001, AES information document for room acoustics and sound reinforcement systems - Characterization and measurement of surface scattering uniformity published 2007-02-13, closed without unresolved comment. AES-4id-2001 (r2007) is reaffirmed.

• Call for comment on DRAFT REVISED AES-2id-xxxx, Guidelines for the AES3 interface
  

  A Call for Comment on DRAFT REVISED AES-2id-xxxx, AES information document for digital audio engineering - Guidelines for the use of the AES3 interface, published 2006-12-28, closed without unresolved comment. AES-2id-2006 has been published (see above).