Delay Compensation

[Pochflyboy]

Hey,

Part of my production uses a large screen mobile screen that sits on the back of a truck. These are great but the only issue is by the time I go through my video switching trailer and into the big screen there is an inherent delay of about 500ms or maybe even a bit more. Is there anyway for me to delay the audio in a video cue within SCS so that I can easily make the sound match the delayed video on the screen?

Thanks,
Joe

[Eric Snodgrass]

I believe you need to delay the audio after it leaves SCS and goes into whatever mixer you are using. Usually the audio guy can delay it, especially if he is using a digital console that has built-in delay. It would be better anyway for the audio guy to delay it because the delay in the house could be different from venue to venue and event to event.

[charlier]

If you use the SoundMan-Server audio engine version of SCS, you can do internal delays for each output and even specific delays at each crosspoint and vary them over time without artifacts. I'm not sure exactly how SCS provides the controls for these at this point however.

[Pochflyboy]

Delay on a board is usual used as an effect and not really for this issue. I did not know that about the SoundMan Server. I should look into that. Thanks, that would be a great solution.

[Mike Daniell]

Eric's solution is what I would recommend, ie using delay on the console. Delay is not only used for 'effect' - it is also used in auditoriums where you have speakers down the sides, etc, to delay the audio to the speakers further from the stage. The delay time is typically set by listening for a clean output with no apparent echo. The theory is that the delay time should equal the time taken for sound to travel from the front speakers to the speaker who's delay you are setting. Sometimes the delay is made a few milliseconds longer than that so the audience still gets the impression the sound they are hearing is coming from the front.

As Charlie points out, SoundMan-Server does have delay available but SM-S does not handle video files so it would be necessary to encode a WAV file from the video file and play that in parallel with the video file. Also, SCS currently doesn't support the SM-S delay feature.

[Pochflyboy]

So basically just dial it in like I would for the delay towers on the board? That makes sense I was just thinking about it the wrong way... I was worried as our matrix has delay for the separation of the PA in it but I spose I could just delay the aux input the same way and it will all work fine adding to the sum of delay that I will need in total across the soundfield.

[Eric Snodgrass]

So basically just dial it in like I would for the delay towers on the board? That makes sense I was just thinking about it the wrong way... I was worried as our matrix has delay for the separation of the PA in it but I spose I could just delay the aux input the same way and it will all work fine adding to the sum of delay that I will need in total across the soundfield.

Yes, exactly. Put the delay on the input of the audio from the video. That way it will not affect any delays already set for the speakers. I do not know what type of board you are using but if it is an analog board you should consider purchasing an outboard delay unit (dirt cheap these days) and patch it on the insert points of the input, or even put it inline between your video playback computer and the board. The delay compensation setting usually will come out to anywhere from 250 to 400ms.

[Pochflyboy]

WE are using a Beheringer x32 console this year. I would be shocked if it could not do it. I will ask the audio guy though. I am not an expert when it comes to live sound engineering.

[Eric Snodgrass]

WE are using a Beheringer x32 console this year. I would be shocked if it could not do it. I will ask the audio guy though. I am not an expert when it comes to live sound engineering.

Just a short viewing of the Behringer X32 site doesn't reveal a delay capability on each channel. It appears that the channels only have built-in Gate and Compression. Having said that, there is probably some sort of plug-ins that can be used on a per-channel basis, including a delay plug-in.