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AES Section Meeting Reports

Los Angeles - August 27, 2013

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Summary

On Tuesday, August 27, Studer rolled its 53 foot semi-truck filled with Studer Consoles and other professional audio
equipment for the monthly AES Los Angeles meeting.. Studer sent its Director of Sales for the US, Rob Lewis, as well as
Paul Shorter and James Tunnicliffe, both support engineers who were on hand in the truck for demos and to answer any
questions about the gear.
Rob gave the society a brief presentation on the state of Audio over Ethernet and Audio over IP, prior to releasing
the group to the equipment.. Rob calls himself a "console guy," but felt that because so much of the future of audio
recording, transmission, and distribution is riding on packet-based technologies, an overview and some examples of how
they're being used today would be useful to the group.
In his talk, Rob noted that the functions of Capturing, Producing, and Playout & Record are now frequently linked
together over a Gigabit Ethernet infrastructure. Live mixing consoles, like the Studer Vista line and the Soundcraft Vi
line (which share some common technologies) can often be integrated into these environments. In doing so, though,
special attention must be paid to seeing that Ethernet packets get to their destinations in the order and time at which
they need to.
In conventional digital audio, (MADI and AES), audio is dependent on precision timing through some kind of
studio clock, and hardware distribution through dedicated, wired links. Each link's bandwidth is devoted entirely to audio
transmission, unlike the shared packet environment of an Ethernet network. There is almost no protocol overhead since
there is very little routing or switching information carried in the stream, aside from channel assignment.
In contrast, manufacturers have taken two approaches to Audio over Ethernet: Layer 2, and Layer 3. In both
cases, many thousands of channels can be routed through standard Ethernet switches, as long as the bandwidth is
available.
In Layer 2 AoE (Audio over Ethernet), robust hardware is the determining factor of whether audio will be
distributed and played back properly. Delay or robustness of signal is determined entirely on how quickly Ethernet
packets can be switched through the various devices and arrive at their destinations. Layer 2 installations require a
dedicated switching environment, but can be used in a number of network topologies including point-to-point, star, and
tree. Layer 2 is being developed in IEEE working group 1722. Audio-Video Bridging is an example of a Layer 2 protocol
as well, but is being developed under IEEE 802.1Qat and 802.1Qav.

Layer 3 AoIP (Audio over IP) is in principle more flexible, in that it uses routable UDP packets rather than the
more basic Ethernet packets to transmit audio signals, but at a cost of needing a much more tightly managed network
infrastructure. Because often other packets can be competing for bandwidth on the network, audio packets must be
given absolute priority through the implementation of some kind of QoS (Quality of Service) rules. Statistical behavior
can provide real-time behavior, but not without the risk of dropouts, as you might see on a congested YouTube feed.
Nevertheless, to achieve transmission at a distance, some kind of Layer 3 protocol must be used — Layer 2 is not
enough to break outside the LAN.
Unfortunately these two protocols are not interoperable. Different manufacturers are still pursuing differing
standards, and not enough commonality has yet been achieved to guarantee that one product will talk to another
product.
Nevertheless, some manufacturers are providing products that are already changing the way that live audio and
video production is being achieved. Rob went on to describe a recent example from the London Olympics, where
Swedish Television used a product from NIMBRA, a Swedish audio company, to transmit the audio feeds from London
back to their studios in Stockholm. Rather than sending a remote truck, they attached only their Studer D21 I/O box in
London to the NIMBRA Net Insight transmitter/receiver, connected it to dark fiber to Stockholm, and reconnected it at
that end to another Net Insight device and Studer D21 I/O. The control room in Stockholm was thus able to achieve
remotely a level of control over the feeds that they'd never had before — control down to the mic pre-amps from nearly
2000 km distance. MADI was used to encapsulate the stream.
The Studer Truck:
Following the presentation on Audio over IP, we were invited outside where the Studer truck awaited. Studer's
demo truck is packed with state of the art, very expensive production consoles. Studer decided to build the truck to
create what they saw as the ideal demonstration environment for their products — it's not limited to a location, and
because the environment can be carefully controlled, they have much higher confidence that their products can be set
up and shown quickly, without worry about integration on site. Thus the two or more long days of setup time at a typical
trade show can be cut way down, and no one has to worry about the uncertainties of factors usually beyond their
control. It has two home bases, one in Southern California, and the other in Elkhart, Indiana.
Toward the rear of the truck is the Vista 9, their flagship product. It is designed for live broadcast production,
and here in Los Angeles, consoles are owned by Fox, the NFL and DirecTV, among others. It is capable of over 350
channels mixed to 150 busses, with up to 1728 inputs/output through its built in touch-screen router. Fox and the NFL
have already used up to 1052 of the available channels. It features their control system called Vistonics, which as Rob
Lewis describes it, "Where I touch is where I control. There's no paging. That's a pretty heavy statement. But there's
no paging on the surface. I touch the EQ and this is now my full four-band parametric EQ. If I touch the green, now I
have my compressor. OK, expander, gate, all right here. And if I hit yellow, I know have my pan, from 7.1 down to
mono. So it's just really simple for the operator to touch and have these controls."

The console is based on a large LCD screen with an
overlay of non-mechanical knob controls. The knobs are
placed on spindles, but have ridges at angles to allow for
feedback to the console much like an optical mouse rolling
over a mousepad. They report that the reliability of the product
has skyrocketed due to the reduction in mechanical parts.
The virtual nature of the LCD surface also allows very specific
information to be conveyed to the mixer — when a spike in
audio occurs, it is possible to see exactly what input is causing
the issue, not just an aggregate of many channels mixed
into a bus.
Because the console is remote from the D21 I/O box,
which is rack mountable, the hardware design has also allowed
them to add a second, smaller remote console as a
backup or second operator station. Studer's software does
not currently support the addition of a third console but the
hardware in principle (which is interconnected via Ethernet)
could allow that in the future.
Other products on display in the truck are the Vista 5,
which is quite similar to the Vista 9, just in a smaller form, and
the Vista 1, which includes the DSP and the IO in the console
itself, more for a live mixing environment. The Vista 1 has 32
mic pre's, 32 line-outs, 8 AES stereo i/o, dedicated MADI, and
a flexible expansion slot that for one example can even be
used with MADI for up to another 64 mic pre's. The consoles
can be configured at the factory in a number of sizes, but cannot
be retrofitted after sale.

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