SC-02-02 meeting, Online, 2022-05

Report of the meeting of the SC-02-02 Working Group on Digital audio interfaces, held online, 2022-05-06.

The meeting was convened by chair John Grant.

Present were Richard Cabot, Paul Treleaven, John Grant, Al Walker, Junichi Yoshio, Jim Meyer, Hatano Wataru, Stephen Scott, Anthony Kuzub, Kevin Gross

The formal notice on patent policy was read.

The agenda was approved as written.

There were no comments on the report of the previous meeting, held online, 2021-10-04.

Projects assigned to this group but not mentioned here had no action requested or required - see for details.

Open projects:

AES10-R Review of AES10-2020: AES Recommended Practice for Digital Audio Engineering -- Serial Multichannel Audio Digital Interface (MADI)

An enquiry had been received asking whether there is any specification of MADI over twisted pair, resulting in discussion on the reflector re-opening the question (last debated in 2017) of whether to use the same format as on co-ax or to specify the use of Fast Ethernet PHY chips. The former could interwork with the other formats, e.g. using baluns to connect between the different kinds of cable, but the latter would not because the data is "scrambled" to spread the spectrum of emissions and the PHYs need a bigger gap between frames than MADI provides when carrying 64 channels of 48kHz audio. There are a number of products on the market using each version, and it is thought they do not all use the same pinout. J Meyer volunteered to find out more detail. The question of whether AES67 renders MADI obsolete was discussed; the conclusion was that for many installations MADI provides an adequate service and avoids the latency introduced by IP networks as well as the requirement for network management.

One option would be to standardise the compatible version, including choosing a standard pin-out. Another would be to write a report (or a new section in AES-10id) detailing the different versions and recommending best practice. In either case a volunteer would be needed to lead a writing-group.

Other projects:

No activity.


Nothing reported.

New projects

No new projects were proposed.

New business

No new business was raised.

The next meeting will be held in conjunction with the 153rd Convention in October 2022.

AES - Audio Engineering Society