SSL's C100

In keeping with CBS Television City's policy of providing its clients with an optimum selection of modern production equipment, we recently commissioned our first primary digital audio console on a TV stage. Stage 58's primary client, “The Late Late Show with Craig Ferguson,” had used a 48-input analog console for about eight years. As the show grew, this console became too small and restricted the show's ability to give guest bands a top quality sound.

In a cooperative evaluation by the mixers, technicians and management, a Solid State Logic (SSL) C100-40 digital audio console was selected as a replacement. What we found was that like modern video switchers, current audio consoles are difficult to distinguish from routers.

The console we purchased has 240 inputs and 240 outputs. They break down as follows: 72 microphone inputs and isolated outputs, 72 high-level analog inputs and outputs, and 96 digital AES/EBU inputs and outputs. So why did we need so much IO?


A prime feature of digital audio consoles is their ability to use programming to be configured differently with a single button push. This programmability includes fader layout, tracking, auxiliary sends, sub and isolated mixes, equalization, and dynamic processing settings. Just about anything that can be set can be programmed and then recalled with just a push of a button. “The Late Late Show with Craig Ferguson” uses this feature by dividing the show's production into two phases, interview and production.

For the interview segments, microphones and line inputs are arranged to enhance the mixing of that segments. When it's necessary to preproduce a production number, another fader layout is called up. With a single button, the mixer can arrange a constellation of faders that support their mixing style that is unique for that segment. Say we have a musical group; we have had as many as 26 pieces, or a small combo. In either case, the mixer doesn't have to do the grand slide from one end to the other trying to reach faders that are only occasionally used. With a programmable console, the faders most important for the current segment — along with EQ, dynamics and aux sends — can be assigned to be within easy reach.

Each fader can be programmed to function as an individual channel input, a stereo input or a 5.1 mix fader. This flexibility helps in keeping the active mixing surface small and accessible. An example is the audience reaction (AR) mix that is picked up by about eight single microphones. These faders are placed on a hidden layer and bussed to a single stereo fader on the active surface. If necessary, the layers can be exchanged and the AR mix adjusted. It is sometimes necessary to adjust this mix during the show or to isolate a section of the audience. Then with a touch of a button, the AR layer is hidden again, and the more important faders are available. In the past, this would require a separate console or the dedication of multiple faders and console real estate. Now with programmable routing, it can be accomplished at one mixing desk and the individual faders, when they are not needed, hidden.

Programmability also enhances the output routing. “The Late Late Show with Craig Ferguson” typically uses about four videotape recorders with 16 discrete audio tracks. However, when a large or complex musical group is performing, additional recorders are added. Before, the console tracking to the additional machines was limited and required patching to create a different output schedule. Now the only limitation is the number of console outputs.

Programmable output routing can be used in other ways. For instance, it can be used to send selected inputs to selected outputs without any fader involvement. This capability used to require the mixer to interrupt the routine just to send a short clip or production piece for recording though the main outputs.

Main electronics frame

With so much I/O, the main electronics frame looks like a large router with dense and concentrated cabling. SSL even calls is the Centri Core or, more affectionately, “the Crate.” This density and the placement of connectors on both the front and back take up a lot of space. Space was also required for the service loops so that the connectors can be removed for module maintenance and to allow for the rather large turning radius of AES/EBU audio cable.

This was something we missed in our initial planning. Although we had been using AES/EBU low-capacitance cable for about 10 years, this was the first time we had so many concentrated connections. So we found that even though the electronics Crate itself is only 15RU high, we had to allow another eight or so rack units for cable access.

Like many of the compact digital boxes used today, the power supply fans make quite a racket. This means that the main electronics frame needs to be sonically isolated from the mixer. This lack of mixing desk and electronics Crate co-location means another PC for maintenance logging, separate technical power and the necessity for the operators to move to another room to use the zip drive to store or retrieve their setups.

Initially, we did not include the GPI I/O module. As we started to implement the desk into the show, we found a real need for this feature. One thing that had escaped our attention was an alarm for leaving the tone oscillator active on a non-monitored track. With so many tracking options and the necessity to identify each track, it is possible for a line-up or ID tone to be left on unnoticed. With the GPI I/O module, it would have been easy to program an alarm whenever the internal tone oscillator was left on.


SSL has employed a proprietary operating system, and it has been rock-solid reliable. We have been through two software, one firmware and a hardware update, and things have gone smoothly. We have had the same experience with the hardware. After a few failures in the commissioning period, the electronics hardware has been failure-free.

Jay Harmer is a technician at CBS Television City.