Timecode accuracy

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

Re-tuning radios

So, it’s illegal to use channel 69 now, but what if you’ve still got some gear tuned to that region- or is it worth your while picking up second hand gear tuned to other frequencies?

Almost all these modifications require swapping out components in the systems, some are cheaper than others.  Let me know if you’ve got any info on other brands/models (Micron?, Zaxcom?)

Sennheiser price list is up here: [PDF] (prices are ex VAT)

Lectrosonics here: [PDF] (US prices, ex VAT)

Audio Limited 2040’s are around £750+ VAT per TX/RX pair, older models (2020, 2000 series can’t be modified)

Sony DWX series- I’ve been quoted £558+VAT for the DWR-S01D receiver last year.  However I’ve also seen warranty packs in the states for US$215 or so (although not to CH38)

It’s also been pointed out to me that there’s another list on the IPS site (from December 2010): http://www.ips.org.uk/tx-upgrade-costs