Use Case Scenario for Optocore Autorouter at University of Melbourne

The Melbourne Conservatorium of Music was opened in 2018. The building houses three key performance venues; a multi-use auditorium, an acoustically treated concert hall and a multi-use large studio space that can accommodate quadraphonic performances. A multitrack recording studio is located behind the concert hall, and an electronic music studio with a 5.1 channel control room.

OM3 Multimode fibre is run throughout the building with multiple LC patch points available in each of the performance venues and studios. The venues and studios are fitted with DiGiCo SD12 and SD11 consoles, SD Racks and Orange Boxes, all fitted with Optocore on LC/Neutrik Opticalcon connectors. All fibre runs terminate at an optical patchbay. A DiGiCo SD11 sits at the heart of the audio network and handles all of the routing and matrixing of audio signals from the venue consoles and the teaching lecterns. The SD11 outputs to the Orange Boxes which are fitted with a DAC card in slot B to feed analogue audio to the respective system processors, as well as hearing loop systems. The idea of having all consoles and racks on a single loop was to allow the recording studio, located behind the concert hall, to be able to record multitrack audio from any of the three venues in the building. The potential to route audio between venues was also highly beneficial.

Passive optical patchbay & Floor box patch points

The original design for the Optocore network was to create the loop using the optical patchbay. While in theory this would work, in practice it did not. Venue consoles and SD racks were not to remain powered up and plugged in to fibre when not in use. This meant that when a device was powered down, it needed to be unplugged from the fibre and a short patch cable used to ‘loop out’ the open fibre connections. This created situations where the distance between nodes exceeded the maximum recommended by DiGiCo. It also increased the number of joins between nodes, thereby increasing overall loss. We could also not rely on our casual technical staff to loop out the open connections, so this practice was never going to be sustainable. 

My understanding is that the loop never correctly functioned from its inception. There were audible pops and cracks through the venue speaker systems, occurring at random during lectures, recitals and concerts. A situation arose that a performance had to be abandoned due to the audio issues. My predecessor tried on multiple occasions to identify the faults, seeking help from various specialised companies to no avail. It was decided to break the building loop and form discrete loops between consoles and racks in each venue. Analogue patching was used for system feeds. Record feeds were connected via Dante over existing CAT5 patching in the building. This set up has remained stable up to this point, however we are not gaining the full potential from the system.

From the commencement of my employment in November 2022, one of my tasks was to get the Optocore loop functioning. Having had extensive experience with DiGiCo consoles and Optocore hardware from my 18 years in the live events and entertainment industry, I had the knowledge to troubleshoot and identify any issues. I determined that the use of the optical patchbay to create the loop was the weak point in the system, potentially causing data and clocking errors, which were causing the audible pops and clicks in the speaker systems.

While speaking to Tom Allen, a former colleague from Group Technologies, the DiGiCo distributor, who was also familiar with the building, he suggested an Optocore Autorouter may be the answer to the issues we were experiencing, after one of the product specialists at DiGiCo UK mentioned it to him. I began researching the unit and decided this was indeed the missing piece of the puzzle. I contacted another former colleague in the UK, Alex Hadjigeorgiou, who is an expert in digital audio systems and explained the scenario in detail. He was in agreement that the Autorouter was the solution to creating and managing the optical loop and being able to switch devices on and off as needed and maintain connection to devices in use elsewhere in the building. Alex has exclusively used Autorouters in his system designs for Coldplay Stadium Tours since 2017, being among the first to do so in live production.

I presented this solution to university management in order to obtain special funding for the purchase, which was subsequently approved. My intention is to install the unit, begin getting devices online and see if the issues persist. If successful, I can begin the path back to having the audio transport carried out entirely over fibre. We can test multitrack recording in the main studio from all venues. Once fully implemented, we will be able to power down venue consoles and ensure audio from teaching lecterns always remains live, which is critical for day to day running of the venues. The fact there is no need to configure the Autorouter is a huge advantage. That it detects optical traffic and opens and closes slots automatically is also greatly beneficial to the smooth operation of the venues. 

Since the installion of the Optocore Autorouter, Conor has provided us with an update:

... An update on our use of the Optocore Autorouter that we purchased in July last year, and never managed to get to it. I ran some tests during the second half of last year, but given how busy the Conservatorium is, I wasn’t able to take the building offline until the week before Christmas. I spent close to 2 days getting the unit installed and the fibre run to it via the optical patchbay. One thing I did discover was I needed to swap the A & B fibres on one end so the send/receive lined up correctly.

Post New Year I had all the DiGiCo consoles and racks plugged in, remapped all the Audio I/O and set up the Optocore Send and Receive ports to pipe audio through the building. I ran several tests and tried to replicate the clocking faults we had previously encountered, and it remained rock solid. We’ve kept the Optocore loop in place for the start of semester, and it’s running perfectly. The analogue audio from the Extron XTP Lectern systems runs into our Master SD11 console and so far hasn’t caused any errors. We’ll be able to run multitrack records from the concert hall back to the studio once they start to ramp up later in the semester. .

The Autorouter has provided us with the solution we needed to make the Optocore loop function as designed. Again, thank you both for the time and support over the past year with this project. I’d be happy to show you through the building at any point and give you a run down of our fibre network and how the Autotouter has been integrated. Please just let me know and we can organise a time. Thanks...."

Conor Dunne – Technical Resources Coordinator, Audio

OPTOCORE AUTOROUTER FEATURES

• Creates an intelligent star out of Optocore ring topology
• Supports any Optocore system – standalone Optocore, Digico opto links or ProGrid by Clear-Com
• Also supports AVB of S6L AVID and Yamaha TWINLANe
• Closes the Optocore loop automatically when active device is switched on/off, added or disconnected
• Plug ’n’ play
• Up to 20 x dual Link duplex Ports for Optocore protocol connection
• No fan
• Dual power supply with automatic switchover
• 2RU Chassis