MOTU Digital Timepiece

Three years since it was first announced, MOTU's Digital Timepiece is here at last. Bristling with features, it aims to become the one‑stop solution for the digital project studio's AV sync needs. Mike Collins explains how to get clock‑wise...

Are you using a Pro Tools system along with an ADAT or a Tascam DA88 or 38? Maybe you're putting music to video using Emagic Logic Audio or Mark Of The Unicorn's Digital Performer? Have you recently bought a Yamaha 02R or 03D, or are you perhaps planning to get the new Mackie digital desk? Until now, you've probably been running a MIDI sequencer locked to a SMPTE code coming from an audio or video tape machine, and all you needed was a SMPTE/MIDI converter. But now you're going to need a new sync box that will keep your digital audio devices all running in step with each other and in step with any SMPTE coming from analogue audio or video machines.

Mark Of The Unicorn's Digital Timepiece (DTP for short) has been a long time coming. It was first announced at least three years ago and shown at various audio exhibitions — where several criticisms of the original design were made, along with some positive suggestions for improvements and additions. Wisely, it was held back until all the suggestions for additional features could be incorporated: the first production units finally showed up in the shops just a short while ago.

In Control

MOTU are known for their MIDI Timepiece and other popular MIDI interfaces, as well as their Digital Performer software for the Macintosh (my favourite MIDI sequencer). You might be thinking that you need a Mac to control the DTP — but, fortunately, this isn't the case. All the basic settings can be made using buttons on the front panel; however, you do need to use the supplied ClockWorks software for the Macintosh if you want to access all the advanced control features (MOTU plan a PC version eventually, but none is available yet). For instance, ClockWorks lets you set the DTP to feed the output of your VCR through the DTP to your video monitor and overlay SMPTE on screen, so that you can see where you are, timing‑wise. You can also display status information about the DTP settings you are using, which can be very helpful at times, and you can display your own text messages on screen — such as the name of the client or the project.

For anyone putting music to video, the features on offer are superb. The Digital Timepiece can generate and slave to every variety of SMPTE timecode, including LTC, VITC and MTC, and it supports both 44.1kHz and 48kHz sampling rates. It also offers 0.1% pull‑up and pull‑down at both sample rates — an essential feature for anyone working with film cues that have been temporarily transferred to NTSC video for music scoring or audio post‑production, as it allows you to avoid sync problems arising from the 0.1% speed difference between the film transfer rate of 30fps and the NTSC video playback rate of 29.97fps. This is not so common here in the UK, where video is normally in PAL 25fps format, but can be important if you need to cover all eventualities while working to picture. The DTP also supports the Sony 9‑pin machine control format, so you can slave a Sony 9‑pin compatible video deck to the DTP or vice versa. This way you can control the video deck, along with all of your other gear, from any MMC‑compatible computer software or hardware controller.

Anyone thinking of using an ADAT or Tascam DA88/38 is going to love the Digital Timepiece. You can hook up a chain of ADATs and Tascam units and control all of these using the DTP's MIDI Machine Control (MMC) transport and record functions. Using the ClockWorks software, you can even program SMPTE timecode offsets for a single ADAT within a chain of ADATs, or program individual track offsets for ADATs or DA88s. So you won't need to shell out for an expensive Alesis BRC or Tascam RC848 unless you really need the advanced functions available on these, and are prepared to pay for the privilege.

Clocking Out

The DTP can also output wordclock to devices such as Yamaha digital mixers, Sonic Solutions digital audio workstations, professional DAT or CD players, and digital outboard equipment. Digidesign use a non‑standard wordclock running at 256 times the speed of the standard clock used by everyone else (probably to encourage people to buy Digidesign synchronisers), but fortunately, the DTP offers x256 wordclock input and output for use with Pro Tools systems. And you can also synchronise to the clock signals within an S/PDIF

The DTP has the functions of at least three separate boxes in one unit — a master clock source, a machine control synchroniser, and a SMPTE/MTC synchroniser.

audio feed, or generate and output a clock signal via S/PDIF — particularly handy if you're using Audiomedia cards, which don't have separate wordclock sync inputs. Previously, if you were using, say, Logic Audio with an Audiomedia card, your sequences would be likely to drift over time because there was no way to resolve the Audiomedia card's clock to external timecode. There has always been a software option in Logic Audio and the other MIDI + Audio sequencers that adds or removes samples as needed to stay in sync with external timecode, but this degrades the audio quality. Another method was to chop the longer audio regions into many short regions which would then be re‑triggered before drift became too noticeable. Neither of these was an ideal way to work, and now you don't need to make these compromises, if you use the Digital Timepiece.

Working To Picture

I get lots of calls from composers working to picture who are not totally sure about the best way to set everything up to sync to video. To make this clear, it's worth considering the three primary components involved in a synchronisation system for video, digital audio and MIDI equipment. First of all, a rock‑solid clock source or 'timebase' is needed for all your digital audio devices to synchronise their clocks to. All digital devices have an internal clock, but professional models and many consumer models can sync to an external clock. Video devices normally sync to a video 'black burst' or 'house sync' signal supplied from a very high‑quality video sync pulse generator. Ideally, you should always use a video 'house sync' signal connected to the Digital Timepiece's Video input as the timebase master for your system, because this will provide the most stable clock source to use as your timebase — and you will also get the fastest possible lock‑up times when the DTP is using external video sync. Secondly, a timecode address is required to identify where you are within the piece you're working on. This may be derived internally from the DTP or externally from Sony 9‑pin, MTC, LTC or VITC sources. Finally, Transport Control (ideally MIDI Machine Control or Sony 9‑pin machine control) is required to allow you to play, stop, rewind and cue all the devices in your system from whichever of these devices is acting as the master controller.

So, with the Digital Timepiece at the hub, you can set your system up to control your video deck along with a whole rack of ADATs and any other MIDI Machine Control‑compatible devices, using the transport controls of a MIDI sequencer running on your computer. The timebase master is either the DTP or house sync; the sequencer is the Transport master, sending MMC commands to the DTP, which in turn controls everything else. In this scenario, your video deck needs to be able to slave to SMPTE timecode sent by the DTP, or it needs to support Sony 9‑pin machine control or MIDI Machine Control. If your VCR has none of these features, you will never be able to slave it to the DTP: you'll have to use the VCR as both transport and address master — using its transport controls to control everything else in your system and sending LTC or VITC to the DTP to let all your devices know where they should be positionally.

One thing to watch out for is that when cueing to a SMPTE location several minutes away using 9‑pin control, the DTP will only wind the video forward at twice normal speed — which is nowhere near fast enough. I ended up manually cueing to the approximate position rather than waiting for the DTP to take me there automatically. It would be nice if MOTU could sort this one out.

There are two final points I'd like to make about working with the DTP. Firstly, if you are working to picture using the Digital Timepiece, it's advisable to use a professional VCR with Sony 9‑pin or MIDI Machine Control capabilities, rather than a consumer VHS machine. Also, working with Pro Tools is not quite as convenient as working with the MIDI + Audio sequencers, because Pro Tools doesn't support MMC! Digidesign need to get their act together here, but in the meantime Pro Tools users can switch to MOTU's ClockWorks software to initiate MMC commands if they don't mind the slight inconvenience.

Verdict

The Digital Timepiece works with a wide combination of digital recording hardware and outboard, as well as MIDI + Audio software and video recorders. What more can you say? It's the near‑ideal sync box to use in a digitally‑minded project studio, especially if you're working with video.