Master Clocks for Post

[breaktheory]

I was reading an article in last month's SOS about master clocks, why we need them, when we need them, how the big ben stacks up against the isochrome etc....

What confused me was that they mention all sorts of studio scenarios and how it's possible to get by without an ext clock...however, when they get to post and working with video they say it's ESSENTIAL to avoid a drift between video and audio.

I've been editing to video w/o an ext. master clock for about 3 years now on my LE system but never in a multi editor mix room scenario...when SOS says "essential" are they just referring to dub stages with multiple PT systems that need to lock in to one master video?

[charles maynes]

unless you are slaving to a multi-device digital chain, OR need to run a pulled up or down sample rate, they would be a waste of time if working with a digital picture.

just my opinion.

[Whitecat]

yeah, sorta sounds like someone who hasn't done post since the late 1980's or something who wrote that article.

working almost entirely ITB as I and many, many, many others do, it's not necessary. and even then, I think they might be confusing clocks and burst/sync generators...

as you say, multiple systems, yes... but with LE, assuming you're loading in quicktimes for the mix, don't worry about it!

[breaktheory]

Originally Posted by charles maynes

unless you are slaving to a multi-device digital chain, OR need to run a pulled up or down sample rate, they would be a waste of time if working with a digital picture.

just my opinion.

That makes sense, I don't really see the value inside the digital world - I'm assuming that these high end word clocks come into play when analog gear becomes part of the chain and the article is maybe referring to some sort of non digital video playback? Sound on Sound seems to know their stuff so I was confused.

That said though, on a dub stage does the recordist use a master clock to keep everyone's sessions synched to the video he's projecting?

[charles maynes]

most stages will have many systems which they resolve to blackburst. As to the timecode resolution, that will typically be good down to the quarter-frame.

[breaktheory]

Originally Posted by charles maynes

most stages will have many systems which they resolve to blackburst. As to the timecode resolution, that will typically be good down to the quarter-frame.

Not sure I know what you mean by resolving to black burst

[charles maynes]

Originally Posted by breaktheory

Not sure I know what you mean by resolving to black burst

videosync- known as blackburst- it is a holdover from the analog days. Most of the current wordclock generators / timecode synchronizers will accept it a a sync source- though tri-level sync is now far more common due to HD TV.

[breaktheory]

Originally Posted by charles maynes

videosync- known as blackburst- it is a holdover from the analog days. Most of the current wordclock generators / timecode synchronizers will accept it a a sync source- though tri-level sync is now far more common due to HD TV.

Thanks Charles - Hard to keep up

[nathand]

Originally Posted by whitecat

yeah, sorta sounds like someone who hasn't done post since the late 1980's or something who wrote that article.

working almost entirely ITB as I and many, many, many others do, it's not necessary. and even then, I think they might be confusing clocks and burst/sync generators...

as you say, multiple systems, yes... but with LE, assuming you're loading in quicktimes for the mix, don't worry about it!

I didn't read the article, but you sorta sound like someone who doesn't do many laybacks. I guess there might not be as many of us as there are of you, but where I work we layback to Digital Video decks on a daily basis. Last time I checked it was the year 2010.

If you want to sync your digital device to another digital device you need a sync generator. Better make it Tri-Level while you're at it.

[Rick Sanchez]

If you are syncing any two physical devices (video or audio decks, multiple ProTools systems, ProTools to Logic, Nuendo, to any of the above etc) you need to have a stable clock source.

If you are ONLY working in a file based workflow and NOT trying to get two systems or decks to play together in sync, then you can get by with only an internal clock.

If you are an audiophile, or have money to burn, especially working in acoustic music and syncing multiple devices, then something like a big ben would be a worthwhile investment. That said, Sync HD or Sync I/O for ProTools is fine with a tri-level sync or blackburst.

[charles maynes]

adding to Ricks thoughts-

Unless you have these things things sorted out pretty well, a Big Ben or other high resolution clock will be a waste of money-


1- a GOOD listening enviornment- this might be headphones, but if you are in a "regular" room or edit bay, the acoustics of the room will render the clock insignificant.

2- GOOD speakers.

3-GOOD D/A converters - If you are clocking consumer grade D to A's the benefit will be trivial.

For me- if I felt the clock wasnt good enough- (I have PTHD and an a Sync i/o which spends most of its time in the "off" condition) I would first suggest making your room as quiet as possible- either via an iso-box for your computer, or new windows, or better air conditioning isolation. After that was dealt with, I would upgrade speakers and monitor control and then the D/A and then, finally the clock.

I do know some people swear that an external clock is critical to their sound quality, but unless you are able to monitor without other sonic distractions, I would say the money could be better spent.

[Whitecat]

Originally Posted by nathand

I didn't read the article, but you sorta sound like someone who doesn't do many laybacks. I guess there might not be as many of us as there are of you, but where I work we layback to Digital Video decks on a daily basis. Last time I checked it was the year 2010.

If you want to sync your digital device to another digital device you need a sync generator. Better make it Tri-Level while you're at it.

which is why I specifically mentioned burst/sync generators as opposed to "clocks" (as in the SOS article).

I've been there before - and PTLE users generally don't do laybacks, I'm not even sure it's possible (it might be, but I've never done it with that!) - hence my reply was geared towards that sort of rig. I'm really just trying to clarify terminology if nothing else - if you go out and buy a wordclock generator, guess what, it likely won't do what you want it to wrt a picture->audio sync...

and yes, the world is going tape-free, slowly... but surely. (possibly... annoyingly.)

[Fajita]

we're starting to go tapeless @ Discovery. Once it's in the Omneon server... you don't need tapes.

[nathand]

Originally Posted by whitecat

and yes, the world is going tape-free, slowly... but surely. (possibly... annoyingly.)

No annoyance here. I can't wait to be completely file-based.