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Case Study: Virtual NewsMixer

Case Study:  Virtual NewsMixer

The Challenge

Replace an older physical newsroom mixer with a virtual option, utilizing as much existing equipment on hand.   

The Gear

With an Axia Audio network present in the facility (Master Control houses an AXIA Element with StudioEngine), an open port on the AoIP network available and a Mixed Signal xNode that could be assigned to the relatively light local i/o requirements of the NewsBooth, on the surface this was a very cut and dried application for Axia’s IP-Tablet product.  Licensing the IP-Tablet Core software and then unlocking control of the xNode would allow us to build a customized virtual mixer, record bus, and digital VU metering for the channels in question.  A second NIC was added to the PC which would host the IP-Tablet as it would still be used on the office network to run the newsroom software.  The curveball came with the requirement to have bi-directional talkback between the Control Room and the NewsBooth.  With Axia Pathfinder in place, that would be a few quick logic settings, the mixer itself could actually be built within Pathfinder and deployed to the desktop of the NewsBooth computer as an executable.  However, Pathfinder was not in-situ and not in budget, so… Terry and Grant got to work!

The Solution

Building out the IP-Tablet mixer and sorting out the layout is a relatively easy drag and drop process. 
As the channel numbers on the xNode appeared when displayed on the channel strips (and could cause potential confusion for the end user), with some creative formatting Grant was able to edit the text colour to black so the channel numbers ‘disappeared’ into the background colour.  We were then able to then create user friendly labels to describe what specifically was assigned to each channel.  From left to right our faders are:

  • Mic – ingested via the XLR input on the mixed signal xNode.
  • PC Audio – IP Driver connection to the local NewsBooth PC.  This is brought into one of the virtual input sources available on the xNode.  This could also be accomplished via the xNode’s line level input.  
  • Phone – connect to the hybrid.  Mix minus is built out utilizing the xNode’s internal source/destination routing matrix.  We have the ability to rout the microphone to the backfeed.  
  • MCR – this is the master control PGM audio feed.  It is also the channel where the Booth announcer talkback will be present.  The NewsBooth has the ability to listen to the studio feed, as well as send the booth audio to the record bus if there is a guest or interview which may require archiving.  

As for the PGM bus assignments:

  • PGM 1 (blue) – adds to the aggregated Mixer output which can be selected in the control room.
  • PGM 2 (red) – feeds the record bus to the local PC. 
  • PGM 1 (green) – allows for local monitoring of the control room feed, but does not loop “back to the booth” (hence colour being used to differentiate its function).   


Pathfinder would simplify the logic of this process immensely.  However, utilizing the external Studio talkback of the control room StudioEngine, and the 2xGPIO ports of the NewsBooth mixed signal xNode (and Terry implementing a custom soldered DB-15 connector to bridge a connection) we are able to build out a TB interface within the IP-Tablet mixer.  The green “TB to MCR” button on the NewsBooth mixer offers a hold-to-talk connection which routes the microphone in the NewsBooth to the cue speaker in Master Control.  Heading the other way, if the NewsMixer has the MCR channel up and active they can monitor the station PGM feed which will duck and have the Booth announcer’s voice audible when the announcer depresses the ‘Talk to Studio’ button on their Element console.  Depressing that button in the Control Room also triggers a GPIO indicator state being monitored on the NewsMixer (labelled MCR TB on the mixer), so in the event the News reader is cutting audio locally and isn’t monitoring the MCR feed which would carry the talkback audio from the booth, they will still have a visual notification that the booth is trying to get their attention, and can turn on the MCR channel to listen at an opportunity which is convenient to their workflow.  

The Final Product

With IP-Tablet we have the ability to alter the background image (we created a very classic looking textured slate look for this one) and add a station logo.  There’s also the ability to do further customization with the button colours, along with some of the text and faders to match station branding.  The layout is saved locally to the computer which runs the IP-Tablet executable as a .json file so the work put into one mixer can be copied and easily replicated on numerous other workstations with minimal changes required in the back-end to select and route the connections to that specific xNode.  We have a 3 source mixer in this particular implementation, there is potential to have a couple more faders accessible depending on their input type (line, AES, Livewire) if required – the ceiling will be the number of sources and destinations in the xNode’s routing matrix.  The size of the mixer can be adjusted to match your monitor, as well as where the mixer is statically placed on the desktop.  Our user just so happened to have a spare monitor they decided to use as an extended desktop to their primary news computer screen, so the mixer will live solely on that display.  Even better, that monitor is a touchscreen!  As more and more AoIP and virtualized gear emerges in the broadcast industry, the possibilities and changes to studio design continue to open up.  

Have an idea for your studio you want to run by us?  Want to dig more into the specifics of what we built for this project?  Our name is Pippin Technical Service for a reason.  Drop us a line, we’d love to discuss your project and how we may be of assistance.  


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