MADI for it

Despite the rise of new digital audio interfaces such as DANTE and the nascent AVB standards, MADI continues to find favour with the pro audio community. Chris Fitzsimmons finds out why.

First, a little revision note for those of you not familiar with MADI. The Multichannel Audio Digital Interface otherwise known as AES10, was first laid out in 1991 and later updated in 2003.

It defines a method for transporting multiple channels of digital audio over a coaxial or fibre optic cable. In AES10-2003 up to 64 channels of audio are supported, with sampling rates of up to 96kHz and resolution of up to 24 bits per channel.

A final, most recent update (AES10-2008) saw minor amendments made to bring the standard line with the latest version of AES3, with which the standard shares several features.

The standard was initially developed by AMS Neve, Solid State Logic (SSL), Sony and Mitsubishi but it now widely adopted in the pro audio, particularly amongst desk manufacturers.

But why, in the age of DANTE and other emerging standards such as AVB are vendors continuing to launch new interfaces and products that work with the standard?

One of the earliest adopters, outside of the initial development group, was Digico. The company includes MADI connections in every single one of its consoles, including the very latest, the SD11. This 19” rackmount or tabletop mount digital console still finds space for a single MADI interface 18 years after the standard was first introduced, but why?

“At the time it was the simplest way for us to transport large amounts of I/O between console surfaces and remote rack frames,” remarks Gordon. “But, the reason for using it is greater now than when we started. We initially used it to connect Digico products together, now we can connect it to almost any console or hard disk system, using a single format with no license fee attached.”

A relatively new adopter of MADI is Allen & Heath. The company offers a MADI interface card for its iLive mixing and distribution system, which research and development director Rob Clark says has been very successful. The company is also working to integrate MADI into its GSR-24 recording desk.

“MADI is brilliant for point-to-point systems. It requires almost no configuration, it’s very reliable robust at shifting audio from A to B. This is why it’s been an extremely successful method of capturing audio. It has filtered down from broadcast to recording, and to other audio applications, because it’s so flexible. “

Another use for the standard, noted by Clark, is as a bridge between other networks. There are MADI bridges available for almost all the digital audio standards, allowing it to act as common ground between any 56 / 64 channel system.

Soundcraft product manager Andy Brown echo’s Clark’s comments on simplicity. “MADI’s popularity arises from its plug and play operation, combined with a reasonably high channel count from a single cable. It also has very low latency [3-4 samples] and you can combine control data on the same cable without using up any of your audio channels.”

The Harman group includes MADI support in its entire range of Soundcraft and Studer desks, either via built in modules or option cards.

“In the live event and broadcast industries, where higher sample rates are not required, the channel count of 64 is a useful and convenient pipeline size. Even with the 96KHz rate it’s still possible to use MADI, albeit with a reduced channel count,” he added.

Even Roland, which has its own proprietary snake system in the shape of REAC, has a MADI product. Its S-MADI bridge performs bi-directional format conversion between REAC and MADI for up to 40 x 40 channels of digital audio. “It’s simple, reliable and it works,” notes the company’s Phil Palmer.

German networking fanatics, Optocore, has recently launched two completely new MADI products – the DD4MR-FX and the DD2FR-FX. The former offers four BNC MADI ports, while the latter includes two duplex fibre MADI ports.

Each device integrates 128 MADI input and output channels in the Optocore fibre system and the SANE Cat5 based system. The products also include external world clock inputs and outputs, and Ethernet links.

“Optocore’s MADI interfaces were developed specially to interface with different digital consoles and to enable Optocore’s preamp control directly from Lawo, Studer, Soundcraft, SSL and Yamaha boards.

“The main advantage of the MADI format is the high channel count and reliable point-to-point transmission. It’s an open standard so it enables easy integration with different manufacturers.”

So, given the plethora of recent products supporting or dedicated to MADI, is it actually still taking a large chunk of the market in general? 

Not according to Yamaha Commercial Audio’s deputy general manager Karl Christmas. “Yamaha is in reasonably good position to gauge popularity of various formats, as we allow connectivity with virtually all bar AES50. Using the MY card facility, all Yamaha digital mixers and DMEs can connect to one or more of the current range of digital formats.

“We are seeing no resurgence of MADI here at Yamaha. On the contrary, sales are only 60% of the previous two years’. Of the major networking protocols, MADI only represents 4% of total sales this year. This will of course look different with other manufacturers who limit their connectivity to a few protocols including MADI.

“New kid on the block, Dante has made significant inroads in the livesound and install market despite having been on the market for just a short while.”

And what does the future hold for the industry’s favourite old soldier? For the answer to that we need to look at the competition. Most agree that the likely challengers to MADI’s position are Dante and AVB.

Dante, according to Yamaha’s Christmas, has made a significant impact in its short life. But there are others who believe it hasn’t gained much traction, or at least not enough to see off the threat from the license-free AVB.

Roland’s Palmer believes that: “widespread adoption of AVB could be the thing that finally finishes off MADI”.

Digico’s James Gordon worries that increasing sample rates will drive users elsewhere in the medium term: “As our consoles move to higher sample rates, the I/O count reduces dramatically, which in the future will restrict the format. On a positive note, right now almost all brands now support MADI, making it at last a true digital standard.

“There are a number of different formats attempting to be the next standard. Mainly these revolve around audio over IP layer 3 formats such as Dante or AVB. These are certainly interested in the future, although currently they are far from being as widely accepted as MADI.”

Optocore’s Maciej Janiszewski believes that MADI should respond to these two with developments of its own: “The next step for MADI development should be a Cat5-based MADI standard, as Cat5 cables are cost-effective when compared to other media. Optocore and others already have Cat5 solutions, but possible soon there will be an AES approved standard enabling multi-vendor equipment connections.”

Andy Brown believes that MADI will continue to have a future whatever else comes along: “Other computer-type interface standards may be able to match the number of channels but are unlikely to match the transmission distance possible. With low-cost copper cables. Network technologies such as AVB may replace the use of MADI for applications such as stagebox links, but there will always be a place for a MADI connection wherever simple point-to-point connections between different manufacturer’s equipment is required.”
And there-in lies the rub. There are without doubt new and exciting things just over the horizon for audio connections. There always are. However, given the continued proliferation of new standards, and the existing array of options, MADI will remain a safe bet. Like a fine wine, AES10 has only improved in its usefulness with age.

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