FIRE WORKS

An Introduction To mLAN Part 3

Published in SOS October 2000
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People : Industry/Music Biz

After looking at the development of and theory behind mLAN, Paul Wiffen continues his series on this new FireWire-based music and audio protocol with a practical look at the effect it will have on the gear in our studios and how we connect it together.

Last month, I looked at some of the technical theory behind mLAN and how it will function on a protocol level. However, just as you don't need an in-depth knowledge of how MIDI works in order to hook a MIDI sequencer to a keyboard and record some music, it's also not necessary to understand how MIDI or audio data is encoded in mLAN in order to use it! However, there are some basic concepts which you will need to understand to get mLAN working for you. In this instalment we will look practically at how mLAN devices can be hooked together, using some of the devices which have already been announced by Yamaha and others, and then go on to speculate about some of the changes in studios which mLAN might bring about.

The first thing you will notice about an mLAN-equipped product is that its FireWire connectors are not labelled In, Out, or Thru, unlike those for MIDI, S/PDIF, ADAT optical, word clock or any of the other interfaces whose functions mLAN may well take over. This is because FireWire is not a serial interface like all these others, and is bi-directional. In other words, a single cable will carry MIDI, digital audio or any of the other signals in both directions. If multiple connectors are provided on a FireWire/mLAN device, it will be to facilitate the building up of bigger systems, not because you need to have two connections between devices to get two-way operation. This makes life a lot easier, especially if you have multiple devices to put in an mLAN network. Provided different bits of gear are connected somewhere on an mLAN network, they will be able to exchange data in both directions. To take a concrete example of how this will improve things, with serial MIDI, when you wanted to initiate a SysEx data dump or MIDI sample dump between a computer and several synths, you had to make sure that all the synths were connected back to the computer for both the request and the data to be successfully received. With mLAN, as everything is being sent down one cable, you either have all the connections you need or not -- so there will be no more staring at MIDI and/or SCSI cables, trying to work out which one is letting you down, and no more struggling with a computer whose screen keeps bringing up the disheartening message 'The unit is not responding. Please check the cables and connections'.

With digital audio, too, routings will be simplified greatly. At the moment, even if you are using a multi-channel digital interface like ADAT optical or TDIF, not only do you need to make sure devices are connected in both directions, but if you want to reorder or reconfigure the groups of audio channels, you need a junction box-type device which can pick up the individual channels, move them around and repackage them in new groupings for transmission. With mLAN, things will be much simpler and much more like using MIDI channels; you'll allocate a channel address on the transmitting device, dial in that channel address on the receiving device, and it should then pick up the audio from that channel. If necessary, several devices will be able to pick up the same audio channel without any rerouting or wasting bandwidth by duplicating material on multiple channels.

As mentioned briefly in the first part of this series, owners of FireWire-equipped Macs and Yamaha digital mixers will be the first people capable of taking advantage of mLAN, as one of the first mLAN products Yamaha have announced is the CD8mLAN, a YGDAI interface card (ie. compatible with their O-series mixers) with mLAN connectivity. Just like the existing YGDAI cards which offer ADAT optical, TDIF, and AES/EBU connectors, each CD8mLAN will only handle eight audio channels because that is the limit of each YGDAI slot (see the 'Untapped Potential' box on page 154 for more on this). However, in an O2R, you could put four cards in and have 32 channels of mLAN audio I/O. Now, you might reasonably wonder what the difference is between putting in four mLAN cards and putting in four ADAT optical or TDIF cards, which would also give you 32 channels of digital I/O in those formats. The difference would become apparent if you interfaced the O2R with a FireWire-equipped computer. Instead of needing to add PCI cards with four ADAT optical connectors (say four Korg 1212s, two Sonorus StudI/Os, two RME Hammerfall Lites or a Frontier Dakota and Montana) or four TDIF connections (like a pair of Soundscape Mixtreme cards), you merely connect a single FireWire cable from the computer to the first CD8mLAN, saving yourself up to £1500 in PCI cards, and all 32 channels of I/O will then exit the computer on a single FireWire cable. Of course, you will have to use both 1394 connectors on each card to daisy-chain the other three CD8mLANs so that the O2R can receive all 32 of those channels, but you would still have a connector free on the final card to connect onwards to other mLAN equipment.

Even in the case of an O1V or an O3D, which can only take a single YGDAI card doing eight channels, you save the cost of an ADAT optical or TDIF-equipped card in the computer. But it doesn't take too much imagination to envision a FireWire connector on a future mixing desk which will allow all the channels on the desk to be sent and received via mLAN over one cable to the computer.

However, that kind of streamlined connectivity is still a way off. For the time being, the majority of equipment is going to need a stepping stone into the world of mLAN. For many, this will take the form of option interface slots like the YGDAI cards for the Yamaha mixers, or the plug-in option card for the Korg Triton Rack mentioned last month (and since the last instalment of this series was written, news has reached me of a similar planned mLAN option board for Swissonic's AD8 converter rack unit). Unfortunately, not all existing products have the option slots which will allow this kind of update to their interface capabilities.

Fortunately, a solution is at hand. Another of the first generation of mLAN products from Yamaha is specifically designed to welcome existing products into the mLAN fold. The mLAN8P (see page 150) provides a gateway to mLAN for analogue audio and standard MIDI instruments, offering the familar trio of serial MIDI sockets and allowing eight channels of audio in and out plus S/PDIF on both co-axial and optical connectors. The mLAN8P also contains a DSP of the same type used in the O1V, which can add effects to incoming audio, whether it's arriving via the analogue or digital inputs or the mLAN connection. Two pieces of software will be supplied with the mLAN8P, the nattily titled Patchbay and Mixer, allowing you to turn the mLAN8P into either a master signal router or a mLAN mixing desk (where the effects capability will be even more welcome).

I think this will be the first of many mLAN devices which externally feature little more than analogue and digital I/O connectors and a minimal user interface, but whose internal capabilities will be unlocked by computer control via the mLAN interface. In the past, hardware devices have required any number of interfaces for effective computer control, including SCSI, MIDI, RS232/422, and S/PDIF. Now that all facets of the operation of a device can be controlled over mLAN, as well as the I/O of the various signals it needs to process, hardware costs should decrease drastically, and functionality increase. Look for many more devices like the mLAN8E in the future, occupying a position between effects units, mixers and routers.

The third mLAN product Yamaha are planning does the same thing for Yamaha synths as the CD8mLAN does for mixers, but with the DSP and software programs that come with the mLAN8P. The mLAN8E (pictured in the first part of this series) is the optional expansion board for Yamaha synths and other future devices which will provide them with mLAN compatibility. Sporting three FireWire connectors and a serial I/O, it will allow eight channels of digital audio I/O plus MIDI onto the mLAN buss (as with the CD8mLAN, I suspect the eight-channel audio restriction is a result of limitations in the connected equipment).

The mLAN8E's DSP capability should prove most useful, not only for effecting the timbres of the synth the board is connected to, but also for processing sounds from anything else on the mLAN network. The bundled Mixer and Patchbay applications will not only allow the user to control the configuration of the network, but will increase the value of the mLAN8E to include mixdown of both the internal sounds and other networked devices.

The word on the wire is that this month's AES trade show in Los Angeles will see a host of new mLAN devices being announced. So keep your eyes open for mLAN-related products in the News pages of SOS over the next couple of months, and if the number of products shown merits it, perhaps you'll see a roundup from me of all the new manufacturers signing up to make use of this most capable music and audio protocol.

Untapped Potential     One of the possible problems relating to how mLAN will be perceived as it strives for widespread acceptance is that limitations of pre-mLAN gear to which mLAN options are fitted are not improved by the addition of the new protocol. For example, the CD8mLAN YGDAI board for Yamaha's O-series mixers only offers eight channels of I/O per board, making it look as though this is all mLAN is capable of carrying, when in fact the limitation is down to the YGDAI/O-series architecture. There is a parallel here with Korg's support for the ADAT optical interface. When they first introduced it on their Trinity and Z1 workstations, their internal hardware was only capable of generating four separate outputs, even though the interface itself supported eight audio channels. So Korg went back to the drawing board, and when the later Triton workstation was released, it supported eight separate outs. I think mLAN will really come into its own when new synths are being designed with the FireWire connector in the frame from the start and the internal hardware is being built with mLAN's capabilities in mind. Again, this has happened before; it took a year or two after the advent of MIDI before manufacturers started to develop multitimbral synths. Without onboard sequencers (and a proprietary internal allocation of voices), there was no way to allocate the different sounds on a synth to different tracks on a sequencer. But once a synth could respond on different MIDI channels with different sounds (something so common nowadays that we take it for granted), the way was paved for single instruments to be capable of playing all the different parts in a MIDI sequence. I am looking forward to the same paradigm shift in digital audio, when the number of channels that mLAN can pass around is taken into account at the design stage of mixers, synths and samplers. In fact, it may finally allow hardware samplers to catch up with the number of separate outputs we are starting to see with software-based samplers, where each MIDI channel can often have its own stereo audio output inside the computer. But this is only what we can imagine now; and often we do not see the really revolutionary applications of a new interface technology when it first appears. When MIDI was first proposed, everyone was talking about playing one keyboard from another, or using a computer to edit programs and store them. Now both things have happened to some extent, but the real runaway success of MIDI has been sequencing, which got much less press at the time (in fact, Sequential Circuits Model 64 Interface for the Commodore 64 with its built-in sequencer was one of their biggest failures, and it took several years of perseverance by German and US software houses before everyone caught on). Perhaps mLAN will have a similar, as-yet-unknown revolutionary impact on the way we work?