AES Standards News Blog

AES50-2011, AES standard for digital audio engineering - High-resolution multi-channel audio interconnection (HRMAI) has been published.  This new edition revises AES50-2005 and contains amendments resulting from a real-world implementation of the standard.

AES50 specifies a means to carry multiple channels of digital audio in AES3 or bit-stream formats, plus system synchronisation information, over a structured data cable using the IEEE Std 802.3 physical layer. It includes a means to convey arbitrary packet-based data over the link, in addition to the specified audio interconnection.

HRMAI provides a professional multi-channel audio interconnection with a number of distinctive characteristics:

• Support for a wide range of commonly-used digital audio coding formats, including “high-resolution” formats such as high sample-rate linear PCM, and one-bit delta-sigma modulated formats.

• Low and deterministic latency (< 100 μs)

• Use of ubiquitous “Category-5” data cable

• Interconnect span up to 100 m

• High-quality full-duplex clocks transmitted in parallel with audio data

• Full-duplex audio interconnection

• 5 Mbit/sec full-duplex auxiliary data connection, compatible with Ethernet networks.

HRMAI is a high-performance point-to-point audio interconnection, rather than a network (although the auxiliary data may operate as a true network, independently of the audio). It is thus an alternative to AES10 (MADI). AES10 lacks many of the features listed above, which are enabled by developments in underlying technology in the thirteen years since AES10 was introduced. However, for applications which do not need these additional facilities, AES10 will continue to be appropriate.