Metacorder/Mackie/Mac...NOOO!! Drift again!

[tmoesound]

Hello

My rig is adrift and I cant figure it out!

I have a S/D 788t running timecode through my mackie 1220i onyx into metacorder on my macbook pro Leopard.

15 minute take resulted in a ridiculous drift. Timecode was intact but drift was miserable and inconsistent. Used my 788 files and no problem.

Any help would be GREATLY appreciated.

Thanks

Trent

[Richard Lightstone, CAS]

There needs to be a lot more details in order to give a possible explanation to your issue.

- what was the TC rate used.

- how you routed the audio from your Mackie into your Mac (?)

- what your settings were for TC on Metacorder

- what do you mean by "Timecode was intact"

[ccsnd]

Not a timecode issue, it's a wordclock issue.

That mixer has no external WC input. Your only solution is to use something else as your I/O that has either a good WC or a WC bnc you can drive from your 788

[ccsnd]

and before we get into another TC vs WC discussion, it has already been had.

Timecode and wordclock are completely different. Seperate. Independent.

[taylormadeaudio]

Hello

My rig is adrift and I cant figure it out!

I have a S/D 788t running timecode through my mackie 1220i onyx into metacorder on my macbook pro Leopard.

15 minute take resulted in a ridiculous drift. Timecode was intact but drift was miserable and inconsistent. Used my 788 files and no problem.

Any help would be GREATLY appreciated.

Thanks

Trent

Just out of curiosity, why aren't you running your TC from the 788T straight into the 1/8" mic input on the Mac? Metacorder supports this option, and I've never had a problem with it.

~tt

[ccsnd]

that would have nothing to do with the problem. He said his timecode was rock solid.

[pscottm]

the one time i used a mackie unit similar to yours to expand inputs of a metric halo 2882 via digital ins, i had the same prob. clocking errors after about 5 min, which renders audio on those tracks unusable. then i switched to using mackie as master clock (thru AES or SPDIf, cant remember, and it went ok but still made me nervous. in the end i ditched the mackie and got another 2882 which worked flawlessly in any number of configurations for high track counts w boom recorder.

[studiomprd]

" My rig is adrift and I cant figure it out! "

Hi and welcome...

SMPTE timecode "drifting" issues can be pretty complex, and there is a lot more information required; actually, you are the one who needs to start "problem-solving", by figuring out what is drifting in relation to what-else... and then problem-solving some more to figure out it it is constant, or are the issues somewhat random... and then...

[taylormadeaudio]

that would have nothing to do with the problem. He said his timecode was rock solid.

I got the impression the 788T tracks were ok, and that the Metacorder tracks were not... how can the tracks drift if the TC is rock solid? Either it's solid or it's not -- if it's solid, no drift... if it's drifting, not solid? What am I missing?

Anyhow, I agree... more information (and troubleshooting) is needed. FWIW, I've had weird TC issues with Metacorder before... simplified things by running the TC into the Mac(Mini) via the 1/8" mic port, and problem solved... years of drift-free recording, fairly long takes included.

...just my $.02

~tt

[ccsnd]

AGAIN

TC has nothing to do with the problem.

The problem is WC. NOT TC

you can have the best TC clock in the world, but that won't help a WC with a bad jitter.

no need to troubleshoot further. I just told you with 100% certainty what the issue is. (twice)

and once more

Timecode is not wordclock and wordclock is not timecode. they are not connected in any way. you can have a rock solid timecode that has 2 recorders start sample accurate at the same place every time, but if they have different wordclocks they will not end at the same time

timecode is not wordclock, wordclock is not timecode.

one is not the other.

end of story.

[taylormadeaudio]

wow... I'm out

peace : )

~tt

[Philip Perkins]

We have hashed this all out many times here, and many many Metacorder and Boom Recorder rigs have been working successfully and without drift since those pgms first became available. In any situation using them that requires long term sync the sample rate of the recorder HAS to be locked to something ultra-accurate, or it will drift away from the other devices working. The 788 has a great clock, the Mackie has a clock that is pretty inaccurate by video audio standards. Since in this set up it is the Mackie that is your A-to-D convertor, and it isn't looking at an accurate clock, it is not sampling at exactly the same rate as your 788 (and possibly slate and Lockits) so your files will not be the same length as those made by 788. You could record any weird TC on Metacorder and have it sync up by ear or by slate clap if the clock of the interface was accurate. You can have perfect TC recorded in the MC metadata but without the accurate sample clock in the A-to-D you will still be out of sync. I'm not sure if I can see how the Mackie Onyx is going to work as a digital audio interface in this situation, since it has no way to take in an external clock (that I know of). However, you COULD use the Mackie as an analog front end and feed its direct outs to an interface that WILL take a good ext. clock (or will seriously clock itself to incoming TC--sorry, it is still true that some interfaces can do this)--this will work fine. I wish the Onyx WOULD take ext clock, like 01v96. Good luck.

phil p

[ccsnd]

Just for the sake of this topic, just so it doesn't get over confusing to the guy, lets just stay away from the clocking via TC signal. I don't know of a device that does this, but even if there is, I just want to keep this as less confusing to people as possible.

[Philip Perkins]

Just for the sake of this topic, just so it doesn't get over confusing to the guy, lets just stay away from the clocking via TC signal. I don't know of a device that does this, but even if there is, I just want to keep this as less confusing to people as possible.

I'm all for non-confusion, but the interfaces I have in mind (esp Traveler) do what I've been saying they do, and have all along. If you don't think that that is a good way to go I can understand that, but the process does work that way, that feature was designed in and is covered in the device's manual. In any case if the OP wants to have files that are in sync he needs to find some way of clocking his interface--favorite would be a nice WC source like Denecke or Ambient or his 788 or switch to a digital mixer that will take that ext clock.

phil p

[Tom Duffy]

In any situation using them that requires long term sync the sample rate of the recorder HAS to be locked to something ultra-accurate, or it will drift away from the other devices working.

This needs repeating - a Mac on its own will not keep accurate sync, and even using the Mackie, you need to be aware of how accurate or inacccurate the clock crystal is. 100ppm or 50ppm is common, that's up to 10 frames slip in an hour long recording or one frame in a 5 minute clip.

[taylormadeaudio]

I understand the difference between timecode and wordclock... and that timecode is essentially a stamp placed into the metadata at record start... what I apparently didn't understand is that Metacorder doesn't continuously "see" continuous timecode?... so in order to maintain sample-accurate sync over long takes (noticeable after anywhere from 5 to 15 minutes or so?) one needs a wordclock link as well?... so, if I connect wordclock (SD702T-out to MOTU 828mkII-in) I will alleviate the potential for drift in the longer Metacorder takes? That will keep the SD702T and Metacorder file lengths the same... right?

So for most of the long-form jobs I do anymore: as to syncing camera... using SB-T's, but TC only, not Tri-level... on longer takes, we're still relying on the chance that the camera (say, Alexa) clock and the SD clock (in this case, both Ambient) will be close enough that the initial timecode stamp and individual clock accuracy will suffice in keeping things close enough... but anything longer than 5 minutes will require genlock to really remain accurately synced...? right?

~tt

[Philip Perkins]

I understand the difference between timecode and wordclock... and that timecode is essentially a stamp placed into the metadata at record start... what I apparently didn't understand is that Metacorder doesn't continuously "see" continuous timecode?... so in order to maintain sample-accurate sync over long takes (noticeable after anywhere from 5 to 15 minutes or so?) one needs a wordclock link as well?... so, if I connect wordclock (SD702T-out to MOTU 828mkII-in) I will alleviate the potential for drift in the longer Metacorder takes? That will keep the SD702T and Metacorder file lengths the same... right?

So for most of the long-form jobs I do anymore: as to syncing camera... using SB-T's, but TC only, not Tri-level... on longer takes, we're still relying on the chance that the camera (say, Alexa) clock and the SD clock (in this case, both Ambient) will be close enough that the initial timecode stamp and individual clock accuracy will suffice in keeping things close enough... but anything longer than 5 minutes will require genlock to really remain accurately synced...? right?

~tt

Sadly, yes. The clocks in everything you mention EXCEPT the Mackie are great, and will work fine, ie less than a frame of drift in 8 hrs without being connected. The WC from 702 to the MOTU box will work fine--have done this a great deal. But you won't be able to use the Mackie as an A-to-D interface, you'll have to feed its analog outs to the MOTU and clock that for your MC rig.

Re: the Alexa--I've been through several versions of what the recommended practice is for the sort of shoots most of us do. AT the moment received wisdom (from the rental house) is to use a Lockit with only TC connected, and the Alexa in Ext TC mode. If another theory has come along in the last few days please someone enlighten me.

phil p

[Tom Duffy]

I understand the difference between timecode and wordclock... and that timecode is essentially a stamp placed into the metadata at record start... what I apparently didn't understand is that Metacorder doesn't continuously "see" continuous timecode?... so in order to maintain sample-accurate sync over long takes (noticeable after anywhere from 5 to 15 minutes or so?) one needs a wordclock link as well?... so, if I connect wordclock (SD702T-out to MOTU 828mkII-in) I will alleviate the potential for drift in the longer Metacorder takes? That will keep the SD702T and Metacorder file lengths the same... right?

So for most of the long-form jobs I do anymore: as to syncing camera... using SB-T's, but TC only, not Tri-level... on longer takes, we're still relying on the chance that the camera (say, Alexa) clock and the SD clock (in this case, both Ambient) will be close enough that the initial timecode stamp and individual clock accuracy will suffice in keeping things close enough... but anything longer than 5 minutes will require genlock to really remain accurately synced...? right?

Yes and Yes. If the clocks are professional grade in everything you are using, you don't need the wordclock (or genlock from the SB-T to the camera).

How accurate does professional grade have to be? Well the NTSC spec says 3ppm (*1), and Ambient based products can be tuned to less than 1ppm.

*1 actually it says 3.579545MHz +-10Hz, which is just less than 3ppm

Tom.

[taylormadeaudio]

Thanks gentlemen,

... oh and Philip, the OP mentioned a Mackie Onyx -- but I'm actually using a Cooper 208, and my I/O is the MOTU 828mkII... no Mackie in the equation (no offense to Mackie - my first boards were Mackie - served me well)

I'm glad to have a better grip on how Metacorder uses timecode though -- for some reason, I always assumed Metacorder was constantly "taking in" TC data - not just the initial metadata at REC start.

Anyhow thanks, and thanks to thesoundguy for your tenacity in pounding the concept home ; )

~tt

[Philip Perkins]

Thanks gentlemen,

... oh and Philip, the OP mentioned a Mackie Onyx -- but I'm actually using a Cooper 208, and my I/O is the MOTU 828mkII... no Mackie in the equation (no offense to Mackie - my first boards were Mackie - served me well)

I'm glad to have a better grip on how Metacorder uses timecode though -- for some reason, I always assumed Metacorder was constantly "taking in" TC data - not just the initial metadata at REC start.

Anyhow thanks, and thanks to thesoundguy for your tenacity in pounding the concept home ; )

~tt

Sorry for my confusion--lucky you with the 208. Anyhow, the SD recorder WC and TC with a MOTU box w/ MC served me very well for a long time, incl some really long sync rolls (4+ hrs). Mackie would have a really great product on their hands if they WOULD add ext sync to the Onyx. When they first came out I asked a really good tech if it was possible to add Ext sync to the that mixer and was told that it really wasn't in any reasonable way. If anyone knows of someone who successfully did this I'd love to hear about it. Ditto the Presonus 24.

phil p

[ccsnd]

Thanks gentlemen,

... oh and Philip, the OP mentioned a Mackie Onyx -- but I'm actually using a Cooper 208, and my I/O is the MOTU 828mkII... no Mackie in the equation (no offense to Mackie - my first boards were Mackie - served me well)

I'm glad to have a better grip on how Metacorder uses timecode though -- for some reason, I always assumed Metacorder was constantly "taking in" TC data - not just the initial metadata at REC start.

Anyhow thanks, and thanks to thesoundguy for your tenacity in pounding the concept home ; )

~tt

That is how everything deals with TC. It's a start flag in the metadata.

thats it.

[Philip Perkins]

That is how everything deals with TC. It's a start flag in the metadata.

thats it.

[Jeff Wexler]

I'm glad to have a better grip on how Metacorder uses timecode though -- for some reason, I always assumed Metacorder was constantly "taking in" TC data - not just the initial metadata at REC start.

~tt

All file based recording utilizes "time stamp" routine, not the continuous recording of linear timecode as used in linear media based recording systems (like tape). The timecode stamp at the beginning of the recording is used as a start point from which "linear" timecode addresses are calculated throughout the running time of the take.

[davidm]

Just for the sake of this topic, just so it doesn't get over confusing to the guy, lets just stay away from the clocking via TC signal. I don't know of a device that does this, but even if there is, I just want to keep this as less confusing to people as possible.

Just in case anyone does want to know about deriving wordclock / digital audio sync from timecode.....

Historically, this goes back to the introduction of computer based editing systems having to accurately follow timecode either from an analogue tape recorder or a VCR. The solution was to gearbox the editing systems speed (wordclock) from the timebase of the incoming LTC. A good example of that technology in production today is the Nunedo / Colin Broad Electronics Syncstation. http://www.steinberg...n_details0.html

As Philip Perkins noted, Mark of the Unicorn have included timecode to wordclock software with their audio interfaces - MOTU SMPTE Console. My first Metacorder setup in 2005 used a MOTU Traveller and the software looked as though it had been around since OS9 days. At the time I used a Lockit with wordclock and didn't spend much time with the SMPTE Console.

Stephen Buckland, General Manager at Sound Techniques here in Auckland has kindly lent me a MOTU UltraLite MK III for the weekend so that I could verify that the software worked. Unlike the Traveller, the UltraLite doesn't have a wordclock input so the SMPTE Console software would be useful if anyone wanted to run Metacorder or BoomRecorder with this interface. Another scenario would be running any MOTU interface with a high quality TC only source.

The test: I sent TC from a Lockit into the UltraLite CH1 audio input and ran AES3 Black Audio from the Lockit into CH1 of a dual trace Oscilloscope. I then connected the UltraLite SPDIF output to CH2 of the Oscilloscope. The Oscilloscope showed SPDIF had no sync relationship with the Lockit timecode / wordclock. I then selected SMPTE as the clock source in the SMPTE Console. Within 10" the SPDIF signal could be clearly seen slewing around the AES3 Black Audio signal. It took about 1.5 minutes to stabilise. At sample level the UltraLite continued to hunt up and down 1.25 samples every 15 seconds or so.

Comparing the TC output from the Lockit (one of the new ACL204 Lockits with dual TC outputs) and the SPDIF signal on the oscilloscope showed the same minor hunting up and down. Practically, the UltraLite has held sample stable sync from a timecode source for past 6 hours of measurement.

[taylormadeaudio]

I've been using the MOTU SMPTE Console for film dialog acquisition since before I ran Metacorder... used it with Digital Performer initially... there's a little amber light on the front of the 828mkII that tells you if you're "locked" or not... MOTU touted it as " sample-acurate sync"... anyhow I eventually stopped using it because it kinda tripped things up a couple of times ( I think -- I was in the field, and didn't have time to experiment or hypothesize a whole lot)... In any case, I didn't feel the need to keep using it that way for what I was doing. I don't recall having had any complaints in the several years since then...

I guess my point is that perhaps this why I assumed MC (and DP, etc.) did something more with the TC than just a file stamp at the top... though it was MOTU's SMPTE Console in the chain that was actually responsible. I always knew it wasn't wordclock, but it seems it functions in a very similar manner?

Anyhow, I think I'll do some tests of my own when I have some time.

~tt