View Full Version : Mix Minus Audio - 455

03-18-2013, 10:13 AM

Much has been discussed about latency issues in TriCaster. This refers to audible and/or visible delay of the output material as compared to the real-time live input.

I would like to propose a feature that would allow for the elimination of audible latency in a live environment. This WILL result in a slight mismatch in the sync of the displayed video, but will prevent a live speaker from hearing audible delay in their voice. And it will still allow for a synchronous recording of the audio and video. This feature would only be necessary in a circumstance where TriCaster was being used to provide some of the audio content of a live presentation, such as from a DDR or the on-board audio player.

This method employs two outboard (non-TriCaster) components. An upstream audio mixer and a downstream audio mixer.

The mic-level output of the upstream mixer is fed to TriCaster. All live room mics are mixed via this upstream mixer.

The proposed feature allows this upstream mixer source audio to go to the on-board recorder as normal, but allows you to deselect any given TriCaster input from the output main audio output of TriCaster (which goes to the amplified sound system).

This is somewhat risky, as without confidence listening it could lead to making a recording without the mixer audio. There should be a switch to allow headphone monitoring of either the main out or the record out. Or perhaps split these options between the stereo channels of headphones. I would also recommend some sort of color change (or perhaps luminance reversal) on the display of any mixer channel which has the "mix-minus" feature enabled.

So the main audio out of the TriCaster would be "Mix-Minus," meaning it contains all audio elements except (in this case) the upstream mixer.

Then one could take either another mic or line out of the mixer, or a DA feed from that mixer, or the Headphone out of that mixer and re-blend that upstream mixed audio with the output of TriCaster using the Downstream mixer.

This would eliminate the audible latency in the house, but would also make the audio and video slightly mis-matched with any live display of the TriCaster video output. However the audio would be correctly synched on the recording.

My assertion is that it is easier for the audience to forgive mismatched visual sync than it is for a speaker to forgive the audible delay of their own voice as they present.


Ken in Denver