MADI: a second coming?

Avid, Roland and SSL are among those launching new MADI devices as use of the open standard protocol continues to grow, finds David Davies
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While the debate about the future of pro-audio technology is increasingly dominated by the emerging AVB standards, a slew of new MADI-supporting solutions from Avid, Lawo, Roland, SSL and other major-name manufacturers suggests that another, quieter revolution may be underway.

Developed by a triumvirate comprising SSL, Sony and Studer, and standardised by the AES in 1991, MADI (Multichannel Audio Digital Interface) allows up to 64 channels of audio to be transmitted down a single optical cable for up to 1.3 miles (2km), along with a limited amount of control data. Near zero latency and fully transparent audio distribution head the spec sheet of a technology that has enjoyed particularly enthusiastic adoption in the broadcast market.

But although the standard could be seen as something of a veteran at nearly 20 years of age, MADI's non-proprietary approach is clearly complementary to the increasing convergence of live, install and broadcast applications. "A FOH guy might be doing a rock 'n' roll show one day, and then a live-to-air broadcast the next," says DiGiCo's marketing director, David Webster, by way of example. "The interface-ability with the broadcast truck is nice and easy if you have a MADI feed."

"As channel counts in live go up and up, and higher sampling rates are being used [more frequently], MADI has come into its own," says Rob Masters, general manager of Synthax UK, which is the exclusive UK distributor for MADIface developer RME. "Combined with the growing support for MADI from many major manufacturers, this has led to something of a 'second coming'."

SSL is among the manufacturers to have responded to the trend, and is introducing two new MADI solutions at IBC 2010: the SDI-MADI de-embedder interface, which extracts up to 16 audio channels from each of the unit's four SDI inputs to provide a maximum of 64 channels in both MADI and AES3; and the MADI-X8 system, which offers point-to-point bulk routing, source distribution, device splitting and source aggregation.

As SSL head of marketing Dan Duffell observes, the new products acknowledge "the expansion in real-time live audio requirements among a wide range of clients. For example, a venue might need to move high-channel-count audio between different consoles in separate performance spaces, or send it to multitrack recorders or broadcast trucks. MADI solves a lot of these problems: it allows you to have very long cable runs and transparent audio with no signal degradation, although I think that if it is reaching a tipping point, it may have more to do with the fact that it is an open standard than anything else."

MADI's development is hardly being hindered, however, by a refreshing degree of cross-company co-operation. SSL's Delta-Link MADI HD interface has been recommended by DiGiCo for several years now, while DiGiCo's technical director, John Stadius, recently worked with engineers from Roland Systems Group to ensure smooth interconnectivity with the latter's S-MADI REAC Bridge. The new device enables 40 channels of bidirectional conversion between Roland's proprietary REAC (Roland Ethernet Audio Communication) protocol and MADI, allowing - for example - Roland's M-48 Personal Mixing System to be used in conjunction with MADI-equipped consoles like DiGiCo's SD7, SD8, SD9 and D Series products.

"It is the first MADI product from Roland so I would say that it was 'one giant leap...'," says Roland Systems Group UK GM Simon Lowther. "Although naturally the DiGiCo involvement has been widely reported, we feel that there are many other possibilities for this product. We have existing V-Mixer users that wish to use the S-MADI Bridge with MADI stageboxes and there have been many enquiries [regarding] splits to MADI recording and broadcast interfaces." Lowther adds that the first shipment of the S-MADI REAC Bridge is due to take place in November.

Already available from Avid, meanwhile, is the HD MADI interface - one of three new solutions to assist the use of the company's Pro Tools HD DAW. Enabling the connection of Pro Tools HD systems to industry-standard MADI infrastructures without the need for a format converter, the 1RU rack mountable HD MADI interface is actually the second MADI-supporting solution from Avid in recent months, following the June launch of a MADI Option card for its VENUE live sound systems.

In a seemingly significant indication of Avid's evolving outlook, Tony Cariddi - segment marketing manager for Avid pro-audio - says that "we're very focused on becoming more open and allowing our customers to use our solutions with a variety of third-party tools. Our support for an industry-leading standard like MADI does that."

Recent weeks have also seen Lawo introduce Nova29 - a compact 16-port MADI router that can be used as a stand-alone unit or integrated with Lawo's broadcast systems - while RME continues to enjoy success with its HDSPe MADIface digital audio interface.

"The steady march forward of technology has meant that, with the arrival of the PCI-express bus and evermore powerful FPGA chips, a truly portable MADI set-up is even easier to realise," says Masters. "The RME HDSPe MADIface allows the user to add 64 channels of MADI i/o to his or her laptop via the increasingly common Express-34 format slot. It has both the coaxial and optical forms of MADI covered up to a sampling rate of 192kHz, as well as being able to handle either 56 or 64 channel variants of the format and different native frame sizes. All-in-all, it can pretty much deal with any flavour of MADI thrown at it!"

But while support for MADI continues to increase, there is recognition that the overall landscape is continuing to change rapidly. Observing the increasing control data requirements in live applications, Cariddi says that "MADI won't fully address this need, which is why many other networked solutions have emerged. While these proprietary protocols provide networked audio and control, they don't necessarily solve all of the problems (such as interconnecting two devices from two different manufacturers). As MADI has proven, an open standard works best." 

www.avnetworks2010.com AVNetworks 2010, UBM's essential conference about networking technologies, takes place at the PLASA show on Wednesday 15 September 

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