hippydog wrote:maybe theirs some confusion here
lets stay with the 120 BPM example
When we say we want the BPM from VDJ,
we are not asking for the lights to "sync" exactly on the down beat.
Why? because even with your S2L tool, which DOES actually trigger on every beat, the enherent limitations of DMX512 and the lights themselves means the lightshow will probably NOT be in EXACT SYNC anyways.. (par lights and LED are the exception, but the majority of DMX lights use motors to change position and colors, which have a delay)
ALSO, music changes, yet the enherent "beat" keeps going.. (IE: their are songs where the downbeat completely changes , yet the "rythym" stays the same)
The limitations of DMX512 is only the time a new DMX512 packet takes to create and 'travel' to the fixtures. Which takes in FreeStyler combination worst case scenario about 50 msec in total. (between FreeStyler telling the light to go on, and the actual moment the light goes on - in case of, for example, a LED fixture).
The speed of sound is 343 meters per second (1125 ft/s), meaning that if you are standing 17,15 meter (56,6 feet) from the speakers in the venue, you'll see the lights go on exactly in sync or even earlier.
(And ofcourse some digital amps and processors add an extra built in delay for processing time, could me 5 msec or more...)
For PAR spots you could enable some kind of pre-glow, responds are way faster. Still there would be a small delay, but I can guarantee that that still looks better then just taking the 120 BPM signal.
Pan/tilt movement or any other mechanic operations is a choice to use on Sound 2 light signal. I often choose not to.
Soooo!, a true "sync" of lights to music is actually very tough in real life..
What we simply want.. is if the DJ says the BPM is 120 BPM, then we want the 'light sequence' to switch scenes 120 times every minute.. IE: set the scene time to 500ms.
and if VDJ says the BPM is 60, then we want the scene time to change to 1000ms or 1 second
and we want this to stay the same during the entire song! yet switch to a different scene time automatically if we change songs.. (IE: have Freestyler take its scene time from VDJ's BPM)
The real problem here is internal timing. It is frankly impossible to let FreeStyler (or for that matter any other app) run an internal trigger at 120 BPM wich does not shift a very tiny bit every time from the 120 BPM that VDJ thinks to have. The longer it runs, the larger the offsync will be, until the beat is exact at the same point and then the story begins over and over again.
The only solution for that is FreeStyler and VDJ have a common time-sync source (lets say a simple one, the internal clock of the computer). I don't know if VDJ uses the internal clock of the computer to calculate the BPM. If so, then this is the common time-sync source and will eliminate the shift problem. But my guess is that VDJ does NOT use the internal clock of the computer but uses the sample rate of the current played track (the same way S2L calculates the BPM) that sample rate is played out through the soundcard which has its own internal clock (way better than any other mainboard time source but still can vary more than 0,01%). FS does not have that info at all so it would shift in time all over the place, making the use of any BPM source from any app without proper time sync kind of useless. Setting the speed of the cue by hand or triggering by hand would be more accurate.
Maybe the confusion lies in the fact we actually want something thats actually "not as good" as your S2L? LOL , in fact something simpler?
Its no confision, using the BPM will just be not as great as people like to think.
Your S2L is AWESOME.. I would put it on par with Sunlights! but I've noticed in some cases a "true" S2L trigger can actually look WORSE then a simple static speed change, and as a DJ I don't always have time to "tweek" the settings to get the S2L to "look better" with the song I'm playing..
hopefully I'm making some sense here... and maybe cleared some things up?
Using the BPM of VDJ does only make sense when used together with a real time sync source (or for that matter, a real beat trigger could be the time sync source).
You can do a tiny test: try to make a sequences that has step times exactly on the beat. (the BPM)
Start it together with the song you've choosen with that BPM... You'll see the time shift that -will- occur and how impossible it is.
)
