Most pieces of professional audio and video gear designed for sync sound recording workflows run timecode, so that editors can easily match up picture and video which have been recorded separately. However not all of them can be trusted to run on their own without drifting out of sync. In order for equipment to avoid slipping out of sync, very accurate clock circuits must be used, which require specialised circuitry (temperature controlled crystal oscillators or TCXO). They’re also expensive, so manufacturers often don’t implement them in their products.
I’ve gone through a load of manufacturers specifications to try and find timecode accuracy in equipment and here’s what I found. I couldn’t find any specs for timecode accuracy in a number of products, in fact no cameras meaning they need to be attached to an external source.
Also, timecode alone will not stop picture and sound files being different lengths. High accuracy clocks are also required to feed wordclock on audio devices and genlock on video in order to slave other devices to these rates, otherwise you’ll experience a difference in file length in accordance to how much your clocks are drifting. This can be especially bad on long takes or syncing up live broadcasts
Also each of these figures goes for the accuracy of one source at maximum (specified) drift. if using two of the same source, these figures should be doubled.
| TC Source | TC accuracy (parts per million) | Time to drift 1 frame (mins) @30fps | ||
|---|---|---|---|---|
| Sonosax | 1 | 555.55 | 9hrs 15mins | |
| Zaxcom | 1.54 | 360.7468 | 6hrs 1min | |
| Tascam (specs from HS-P82) | 100 | 5.5555 | 5mins 33s | External Sync necessary |
| Ambient* | 0.2 | 2777.75 | 46hrs 18 mins | (requires tuning for this accuracy) |
| Ambient ACN | 0.1 | 5555.5 | 92hrs 46mins | |
| Timecode Buddy | 0.16 | 3472.188 | 57hrs 52mins | |
| Fostex (specs from PD606) | 100 | 5.5555 | 5mins 30s | External Sync necessary |
| Roland (specs from R88) | 15 | 37.3737 | 37mins | External Sync necessary |
| Denecke | 1 | 555.55 | 9hrs 15mins | |
| Betso | 0.2 | 2777.75 | 46hrs 18mins |
*in Sound Devices 7 series and 664, AETA 4minx, ARRI Alexa and Pre- ACN Lockit boxes
Updated to include Roland R88