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Sound Reinforcement - Forums for Live Sound Professionals - Your Displayed Name Must Be Your Real Full Name To Post In The Live Sound Forums => Lighting Forum => Topic started by: Stuart Anderson on July 15, 2018, 03:35:30 PM

Title: Syncing light with music, considering sound propagation delays
Post by: Stuart Anderson on July 15, 2018, 03:35:30 PM
Just curious...

In programming automated lighting to match my band's backing tracks, I experimentally determine the audio & lighting system delta between 'hearing it' and 'seeing it'.  (This boils down the net effects of audio and lighting software app processing, audio decoding, MIDI & DMX propagation, light rise time, etc. to an observed delta time unique for my particular system.)  I then apply this slight (global and constant) time adjustment to the lighting events so any lighting events intended to match an audio beat look & sound right on the mark.  For my systems, I've found that shifting the lighting program events about 100 msecs relative to the corresponding audio backing track brings it 'in the pocket' with the audio.  Not doing so, even though this is a small amount, makes it look like the light guy is a bit on the klutzy side.

But what about larger venues where the delay of sound due to audience distance from the main speakers can get near this same ballpark (e.g. nearly 60 msecs at 20 meters)?  My band will only play in compact venues where it doesn't matter, but I'm curious if those that deal with larger venues have to deal with instantaneous light versus slow sound, and if so how they handle it?
Title: Re: Syncing light with music, considering sound propagation delays
Post by: Tim McCulloch on July 17, 2018, 11:16:05 PM
Just curious...

In programming automated lighting to match my band's backing tracks, I experimentally determine the audio & lighting system delta between 'hearing it' and 'seeing it'.  (This boils down the net effects of audio and lighting software app processing, audio decoding, MIDI & DMX propagation, light rise time, etc. to an observed delta time unique for my particular system.)  I then apply this slight (global and constant) time adjustment to the lighting events so any lighting events intended to match an audio beat look & sound right on the mark.  For my systems, I've found that shifting the lighting program events about 100 msecs relative to the corresponding audio backing track brings it 'in the pocket' with the audio.  Not doing so, even though this is a small amount, makes it look like the light guy is a bit on the klutzy side.

But what about larger venues where the delay of sound due to audience distance from the main speakers can get near this same ballpark (e.g. nearly 60 msecs at 20 meters)?  My band will only play in compact venues where it doesn't matter, but I'm curious if those that deal with larger venues have to deal with instantaneous light versus slow sound, and if so how they handle it?

You align for the spot where the influential band spouses or whoever signs your cheque stands.
Title: Re: Syncing light with music, considering sound propagation delays
Post by: Stuart Anderson on July 19, 2018, 11:01:30 AM
You align for the spot where the influential band spouses or whoever signs your cheque stands.

Ha!  Always a good tactic...