Professional Sound - June 2022 - Page 27

Luca Giaroli : So , RAI Television hired me as designer and signal distribution manager , asking me to satisfy the high level of resiliency required by the EBU . The most important one is the first level of redundancy , which must be triggered automatically . So , there must be something that is automatically solving the problem without the human being doing anything . That ’ s a kind of a challenging thing , especially because you have to do that for both front-of-house ( PA , monitoring , and in-ear monitoring ) and broadcast . It ’ s a complicated task . Therefore , because RAI has known me for a long time as we are in contact for several reasons , they gave me the responsibility of the design and the programming .
In order to achieve that challenging goal of having the first level of redundancy be fully automated , I deployed 13 different DirectOut Prodigy . MP [ multifunction audio processors ,] which offer plenty of tools to guarantee that automatic switching on several aspects . Basically , the Prodigy . MP offers a different level of redundancy for different aspects . For example , clocking — you can have a hierarchy or priority in terms of clocking . So , you can say “ if everything goes in this direction , I want to get the word clocking from number one …” And then if something goes wrong , I can have word clocking input number two . And then if that goes wrong , I can have the clock extracting from the incoming MADI or from the incoming network .
That is an important thing because the design for the Eurovision Song Contest is completely synchronous .
So , NEP is in charge of the big broadcast vans , which are twinned for redundancy purposes . They are distributing the clock to RAI , which is doing the music mix , and then RAI is forwarding that clock to the stage , and then the stage is getting the clock for everything regarding stage racks , monitor console , and front-of-house consoles . So , if everything goes in the right direction , we are all synchronized to the same clock . But if something goes wrong and for any reason the clock should be disconnected somewhere , each portion should carry on , independently generating their own clock , and therefore , an automatic sample rate conversion , bi-directional , will be immediately inserted to prevent glitches or something like that .
So , that ’ s another of the important aspects of the Prodigy . MP used in the all the crucial points of audio exchange , which are offering several things . For example , for every multi-channel digital IO such as MADI or network ( meaning Dante or Ravenna or whatever ) it ’ s offering automatic sample rate conversion . So , if everything goes in the right direction , there is no need for sample rate conversion — the signal goes straight and synchronous . But the first time that the received signal is out of sync , even if just one sample is out of sync , the Prodigy . MP will automatically insert the first sample rate conversion to solve the issue . So , that ’ s another important aspect .
Last but not least – of course on top of the fact that we ’ ve got redundant power supplies and those usual things – is a redundant connection . So , for example , MADI can be used in pairs to have main and redundant . But also , recently , we developed something called Automator , which is a service running inside of the unit that can offer several triggers . And those triggers combined in a Boolean algebra can stroke different actions . So , if I have something lost and the signal is changing ( for example , if the fast sample rate converter is required or something ), not only is the device reacting automatically , but it ’ s also able to change the settings of external devices . For example , changing the position of a GPO or sending an OSC command or sending an HTTP command or a TCP command . So , the Prodigy . MP is not only reacting to internal changes , but it ’ s also the means of changing other devices in order to overcome the problem of failure , which can happen at any time .
So , combining the word clock recovery , the fast sample rate converter , which is automatically enabled if needed , the Automator , and other redundant features that are built into the Prodigy . MP , I could design a very rock-solid system and the Prodigy . MPs are used in all the crucial points where the signals are either generated or redistributed . For example , starting from the playback rig , we have three Pro Tools rigs . The
first one is having a MADI interface and is considered our main . The second and the third ones are equipped with Dante Virtual Soundcard and are using Dante as a second backup and disaster recovery . Those three Pro Tools rigs are connected to two independent Prodigy . MPs , which are each receiving both main and backup and disaster recovery , and automatically select the one that is currently working . If main is working , fine ; otherwise , there ’ s the backup and then the disaster recovery .
And why two Prodigy . MPs ? Because , as I said , the EBU requires that not any one device could represent a single point of failure . So , if you have a Produgy . MP , which is used to collect the three Pro Tools rigs , but if it ’ s really the Prodigy . MP that fails , then it doesn ’ t matter how many Pro Tools rigs you have because you will lose the entire thing . So , everything is doubled . Everything is doubled and exchanging signals or changing the role inside of the design depending upon the current situation .
So , the three Pro Tools rigs are feeding two Prodigy . MPs . One of the Prodigy . MPs is considered the main one for the broadcast distribution , and the second device is considered the main one for the live performances , but either of them can act as a redundant or a backup solution for the other . Even if the two Prodigy . MPs end up having different clock references , thanks to the fact that ( worst case scenario ) the feed that is not in sync will go through a sample rate converter , that is solving the issue .
From those two Prodigy . MPs , a main central patch room is fed for both broadcast and live . Once again , the patch room is divided into different souls ( broadcast and live ), because at any time the clock