Today’s question is about word clock and how it affects a chain of recording devices. For the sake of our limited space we’re going to spare you the person’s rather lengthy and thorough set up to the question, which is:
“My question is, can a device set to be word clock master “listen” to digital audio coming from a [device slaved to that word clock]?”
Under normal circumstances yes. The important thing that must occur for digital devices to accurately exchange audio data is the synchronization of their clocks. In principle and theory it really shouldn’t matter which one is master or slave, so long as they are synchronized. For example, you could slave the word clock of your digital mixer to the output of your DAT machine and still be able to transfer audio both directions. Pro Tools can slave its clock to an external device and still send and receive audio to or from any other digital device so long as it is slaved (one way or the other) to that same word clock. This is the whole principle behind things like house sync.
In practice things aren’t always as neat and simple, and your equipment may vary in some interesting ways. Some digital devices don’t do a very good job of actually syncing to another device. There are actually tons of specific little problems you can run in to, but as technology progresses things work better and better.
One of the big problems we continue to face is that once you start building a digital studio you’ll quickly become aware of how many digital devices are out there that have no ability to synchronize to external clock. Sure, it’s great to get the digital output option on your new keyboard, but are you really willing to clock your whole studio to that keyboard just so you can run its audio into the system digitally? This is the type of thing we are faced with in setting up our systems. Until more equipment is capable of syncing to external clocks we are still going to have to use analog connections for quite a few things. Fortunately most converters these days sound good enough that this isn’t a huge problem.