In live sound anyone who, like me, started working professionally in the pre-digital 90s or earlier would remember the large splitter racks which would sit on stage and were the the central point in the system. All the inputs from the stage were patched into it and the signals were split into two duplicate sets of outputs, one to the multicore heading off to the front of house mixer, another to the monitor position at the side of stage.
Splitters were always under scrutiny because they were expensive to build properly. The magic words “transformer isolated” were what everyone wanted to hear as that meant that a wiring issue in the split couldn’t affect the main feed. Understanding this, back in the 80s Mike built his own transformer isolated split for his mobile recording business so he could confidently say that the live feed into which he was tapping was a straight piece of wire and if there was an unexplained hum or level change it definitely wasn’t his fault!
AoIP And Dante - Easy Splits
When properly done, passive splits work well but issues will arise if you try to passively split a signal too many times. Active analogue splits came along but were even more expensive with the BSS system perhaps being the most well known. When I first came across the current generation of AoIP solutions like Dante, my first thought was that it was going to make stage splitters obsolete overnight.
That’s pretty much what has happened and the enthusiastic take up of Dante by the live events market has made life much easier for those of us who offer recording or broadcast services to the live events industry, with the possibility of unhindered bridging between Dante networks using mixed sample rates is particularly useful here as live sound productions move to 96KHz workflows while broadcasters still largely working at 48KHz used to be constrictive but using the DAD AX32 in combination with the Dante card means the AX32 can provide all the flexible, crosspoint routing of a Dante network but from within the DADman software.
Returning to the splitter racks of my early career, another very attractive advantage of Dante is the use of installed network infrastructure and some of the earliest early adopters of Dante were universities who bought rolling racks, loaded with Dante IO which could be wheeled in to whichever performance space was required and plugged into a gigabit network port. Working this way full multitrack capture and monitoring can be seamless regardless of the room being used.
This put me in mind of the splitter racks I started out with but where there used to be expense, compromise and lots and lots of cable (so much cable!) there was now a simple and convenient upgrade. I liked it straight away.
I was put in mind of these early adopting universities when I came across the recent install at La Seine Musicale in Paris, a prestigious live venue with an integrated recording studio. Riffx Studio is based around a DAD AX32, a Pro Tools HD system, running on a Mac and for hands-on control and an Avid S6 with 32 faders. The studio also has two rolling racks, each featuring an AX32, one with 32 analog inputs, 8 analog outputs and 8 AES inputs and outputs. The other unit has 16 analog inputs, 8 analog outputs and 8 AES inputs and outputs. These racks can easily, and freely moved, to any room or hall in which a recording session is scheduled. A single Ethernet cable from the rack to a network port in the wall routes all of the channels to the control room in which another AX32 unit is gathering the audio streams. From that point onward, the DADman software’s audio-routing matrix can simply distribute and redistribute to any destination, including Pro Tools, monitors, redundant recordings etc.
The AX32 is a favourite piece of hardware, whereas for use with Pro Tools, the Avid MTRX offers compatibility with DSP systems. While quality costs, this approach is extremely efficient in that the IO is a shared resource between the four recording spaces and the concert halls at La Seine Musicale. The network infrastructure is standard Ethernet and the saving compared to installing analogue cabling is huge. The mobile racks are so quick to install and because configurations for the different rooms can be instantly recalled, it allows the highest quality hardware to be shared between rooms without creating an impractical burden in terms of patch and setup time if they were trying to share conventional resources in this way.
For flexibility in large facilities the advantages of Dante and the AX32 are easy to see but these advantages can also benefit smaller scale facilities. If you want to know more about the Dante system and the AX32 as used in Riffx studios see the article on the DAD website.