Broadcasters are looking for cost-effective
studio and technical solutions. While comparing the acquisition
costs for various mixing consoles, audio routers and the like is
the first step in a comparative process, there is more to
consider. Installation. A few years ago, it was easy to compare
various studio equipment suites because the cost of installation
was pretty much the same no matter what equipment you bought.
All the wiring was “point to point”, and flexible cabling
systems including punch blocks, patch bays, cross-connect wiring
and the like were installed, or not, at the direction of the
facility engineer. Nowadays, there are new methods of wiring
equipment and studios together. Some of these new methods
benefit from some labor-savings over traditional methods. Some
new technology is radically different in terms of the labor
required for successful implementation. This report compares
three studio wiring scenarios, giving tabular and textual
comparisons of the three chief methodologies available today.
Traditional Method
Traditional
studio and inter-studio wiring methods tend to be “console
centric”; the audio console is the center of each studio.
All audio sources and destinations are wired directly into
and out of the audio console. These consoles typically have
a large number of connectors, either behind the meter bridge
or under the console, within the console pan. Many engineers
choose to extend all these connections out to a field of
punch blocks or other cable termination so that additional
wiring may be done without opening the console while it’s in
operation.
Wiring among studios and/or between each
studio and a central wiring area, or “Tech Center” is
usually done with multi-pair audio cables. These cables are
often terminated on both ends by more punch blocks.
Cross-connect wires are then used to connect cable
terminations to console inputs and outputs. This practice
can result in a typical audio feed being “punched down” from
4 to 8 times on its journey from source device to the
transmission path output. Even more connections occur if the
Tech Center employs a central patch panel or centralized
routing switcher.
Traditional studio wiring, indeed, often
begins at the audio console in each studio. Most engineers
can identify with the laborious job of wiring all the inputs
and outputs related to a traditional audio console. Wiring
sources and destinations directly to and from console I/O’s
is a bit more efficient,
but
is inflexible. Connecting console I/Os to equipment through
punch blocks is even more laborious, but offers flexibility
for future changes and additions.
Taken to its extreme, this kind of “point to
point” wiring can get out of hand over the course of several
years, format changes, additions or deletions to the
stations in a given facility.
This photo exemplifies what can actually
happen when a facility is connected using a methodology
inadequate to the facility’s growth needs.
A
more reasonable example of traditional wiring techniques in
a multi-studio facility follows. Here we see a typical Tech
Center wall with dozens of punch block interconnects. Even
when using a centralized routing switcher, an audio path
often includes 4 or more trips through these punch block
connections.
Moreover, additions and changes down the
road involve physical work, moving or adding cross-connect
wiring, and documenting those changes.
Router/Surface Method
A new crop of audio routing switchers and
add-on control surfaces emerged, beginning in the late
1990’s. This class of routers is often called Time Domain
Multiplex or “TDM” routers due to their internal design.
The first router/surface combinations relied
on a centralized audio router to which all sources and
destinations were wired, resulting in wiring technique
similar to the “traditional method” described above. Later
versions have incorporated “satellite” card cages designed
to reduce inter-studio wiring.
While some efficiency was gained and the
amount of inter-studio wiring was reduced, it’s still
necessary to connect all studio sources and destinations to
a single terminal frame, or more often, a set of punch
blocks in one location.
Inter-studio wiring is reduced significantly
– usually to just a few CAT-6 cables and/or fiberoptic
cables. However, since the satellite cages and central audio
routers use high-density connectors, they’re still brought
out to punch blocks for connection to source and destination
gear.
Audio over IP Method
First implemented commercially in early
2004, the Audio over IP method is similar to the networking
of computer peripherals. Audio source and destination
equipment is connected to nearby audio “nodes”. A node
converts analog or AES3 audio to and from an RTP streaming
format. Each node then connects to an Ethernet switch using
a single CAT-6 cable. Modern Ethernet switches and protocols
are employed, ensuring timely delivery of audio-bearing IP
packets to their destinations. The central switch is an off-theshelf
100/1000 Mbps Ethernet switched hub. Other studios are
networked together by connecting their Ethernet switches
together, in a “star” or “daisy chain” fashion, or both.
Audio nodes are installed near the equipment
to be served, reducing cabling significantly. In this
studio, for example, the longest audio cable (excluding the
mic and speaker wires) is 3’ 6” long. Both ends of each
audio wire are visible behind the equipment, so no
documentation is required. Audio wire routing is
self-evident. Those who have installed this “distributed”
audio network system report that installation time and
materials are cut dramatically over other methods.
Installation
of an IP-Audio network represents a departure from the other
methodologies. Resembling a computer LAN in its topology, an
IP-Audio network completely eliminates a number of usual
pieces of hardware traditionally associated with
multi-studio installations. Patch bays, distribution
amplifiers, punch blocks, multi-pair cables, heavy-duty
cable trays, all wall space previously devoted to
intermediate connection systems, and more are not needed.
Moreover, the planning and installation of these items is
also eliminated.
Virtually all audio connections are made
with no need for field soldering and field connectorization.
Most equipment connections are literally “plug and play”
using off-the shelf adapters and cables. PCs used for audio
recording or playback may be connected directly to the
IP-Audio network without audio cards or GPIO devices.
Once the local audio I/O connections are in
place, configuration of audio routing, paths and assignments
is made with a graphical web browser interface.
Each studio connects to the Tech Center
using from 1 to 4 CAT-6 Ethernet cables.
