In a recent discussion with an old friend(JRMintz on the usual groupdiy.com) he mentioned the need for a talkback controller.

Some kind of device that could be used to switch the microphone to pass to the live room. Think of it as a push to talk switch with a microphone.

At a high level, that's simply a dpdt switch that either sends the mic signal through, or ground. Real simple.

But, thinking this through, I decided to expand the idea a little with the following features

  • Onboard electret microphone, so you don't need to burn a waste a nice dynamic mic
  • Onboard Microphone Preamplifier for External XLR or Electret Microphone
  • Audio source switching (so it could be used in a headphone mix path)
    • Select one of 2 audio sources by default, which get muted when microphone is enabled
  • Mono Balanced or Stereo unbalanced support per relay card
    • Not all studio's run their talkback systems in stereo, nor do they run them balanced.
  • Remote button or remote button/mic combo.

Now lets talk a little about form factors

Rack Mount unit - simple unit that has 3 buttons, an electret mic and a small integrated speaker and amp.

Rack Mount Unit + External interface with integrated Mic and single push-to-talk switch.

Rack Mount Unit + Complete Remote Control. 

The Rack Mount unit would look something similar to this:

The grill on the left could contain a feedback speaker from the live room, which would ensure smooth conversation between the control room and the live room.

There's a hole for the electret microphone to be mounted behind the panel.

Not shown in the image above are the mounting holes for the PCB's behind.

In the next blog entry, I'll cover the functionality side of things. how things should work etc. This has a huge impact on the software being developed.



Written by Dafydd Roche — September 16, 2013

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