Topic: timecode question

[kingdong]

I recently picked up a couple Instamic Pro C's.  They seem to present some interesting possibilities for very wide stereo or other non-standard placements.  Running the control app on a phone allows them to be timecode synced which is awfully convenient when bringing together the mono files in Audacity (my primary editing sw).  My recent recorder of choice has been the Zoom F3 (no timecode) and I was thinking about the possibilities presented by being able to combine the Zoom recording with Instamic recordings.  In a first go, I found that aligning the front end of both sources was easy but by the end of an hour recording there was about a 5 ms variation.  Not surprising really and having done it previously, I know I can use Audacity to stretch one of the recordings so that they line up better (but I remember it being a somewhat fiddly process).  What I am wondering is if I could use an Atomos Ultrasonic Blue to add timecode to the F3 (via bluetooth adapter) and also sync the Instamic timecode to the Blue at the same time (I am guessing this is possible)? 
I am using an older version of Audacity and am pretty sure it doesn't pull in/understand the timecode info imbedded in the .wav files but am suspecting that the fact that all recording devices are synced to the same timecode means that I will not see drift between them.  If that is true, then I would only need to align the beginning of the recordings and not have to deal with the stretching.  Does anyone know if this is a correct assumption?
Thanks in advance!

[goodcooker]

Timecode is metadata (a stable running time reference) embedded in the file. It will not sync the clocks of the different devices. It only provides a reference to line the files up in post.

What you need to align the actual clocks in the devices is Wordclock Sync which is not available on your devices. Devices that are Wordclock Sync capable use one clock to be the Master and all others are set to follow it to the sample level.

Think of it this way

Timecode is a clock on the wall that both of your recorders can "see". The internal clocks operate independently but they both can see what time it is.

Wordclock Sync is an internal clock that is on one of your recorders that the other recorder can see (through a pulse code provided by a cable connecting them) and align it's own internal clock to it so that each recorder runs at exactly the same rate (for 48kHz each recorder puts 48,000 samples per second in the the exact same place)

Sharing a timecode source then shrinking/stretching to fit is the only option for using the devices you mentioned. There is a tutorial (created by morst IIRC) somewhere here on TS that provides a formula for stretching files in Audacity that are very close to sample accurate.

[kingdong]

I appreciate the explanation.  I guess that is what I didn't really understand.  My hope was that maybe the device(s) would use the master clock (Atomos device in this case) the keep their internal clock/circuitry (the part that captures 48k samples per second) in sync with each other. 
I guess in my mind I was making it more sophisticated than it is. 

I guess to my current understanding, the timecode gives me no benefit.  Although I can use the app to start the insxtamics simultaneously, that won't be sample perfect to starting the Zoom F3 so I will still have to first line up the beginning of the recordings, then look at some waveform near the end and stretch whomever's sample clock is slower.  If I am missing some hidden benefit, I'd love to hear it...

[goodcooker]

With the growing market segment of consumer level devices being described as "pro" in the video/audio world some of the marketing speak can be misleading.

A device that has timecode is being marketed to users as "features rock solid wireless timecode to perfectly align your audio in post production". That works great for audio clips of a few minutes for video. Not so much for an hour long main stereo pair recording.

Some of this is over my head too. I bought a pair of Movo wireless mics when they hit the market a few years ago. Not sure how two separate mics make a stereo pair recording unless I'm just over thinking it and the clock sync is actually in the receiver not the mics.

[kingdong]

As a followup and FYI about the instamics; they do not maintain a sync to the app as best I can tell.  They start in sync, but over an hour set, I am seeing a difference of 200-300 samples.  It's manageable, but not as hands off as one might like.

[Melanie]

I sometimes do a board/mic mix after the fact because of time delay issues as mics are rarely on stage. I use a pair of Tascam DR 100mk lll which stayed synced up for hours. I do a manual sync and usually can get it right with 2 or 3 tries. I've got the new (to me) Tascam X8 but have not had an opportunity to use it other than to mix board/mic recordings from the DR100s. Hoping to put mics on stage for a 13 pc. Zappa cover band called Stinkfoot Orchestra and use the X8 this summer as a standalone unit. I got really good at manual syncs in the 90s as I did a LOT of video synced with board feeds and sometimes mics. I was using a Quasar S-VHS camcorder and it would sync up and stay on track time wise just fine for 2 hr. S-VHS tapes. Used a Panasonic S-VHS once, time would drift after 20 minutes or so, never rented that machine again, although it was a better low light camera. Bob