what's a word clock for?

[superchow]

Hi! I'm kinda new to the world of digital audio, and I'm just wondering what the "word clock" on the back of most digital audio equipment does....Normally, it comes like as word clock "in" and "out"....thanks!

[ThunderRoadPost]

"Word Clock" is clock information associated with AES/EBU digital audio channels. The clock is needed to synchronize audio data so it can be read by machines connected via AES/EBU.

And to answer your next question:

AES/EBU: The Audio Engineering Society (AES) and the European Broadcasting Union (EBU) together have defined a standard for Digital Audio, now adopted by ANSI (American National Standards Institute). Commonly referred to as 'AES/EBU', this digital audio standard permits a variety of sampling frequencies, for example CDs at 44.1 kHz, or digital VTRs at 48 kHz. 48 kHz is widely used in broadcast TV production.

This digital format is commonly distributed via standard XLR (low impedance three-pin connection [mic cable]) cables.

[Sphyr]

Thunder ain't exactly correct. Word clock is sample accurate timing information. When your doing a digital transfer, the source and the target have to be clocked and running at the same speed with accuracy equal to the sample rate i.e 1/48000 or 1/44100 a second (48kHz and 44.1kHz). If machines arn't clocked proberly, you get word errors. Nasty digital spikes that can be very loud and painfull. You can't transfer digitly between 2 differant sampling. The source and the targets have to be the same usally 44.1 or 48kHz. AES-EBU carries clock information on the first stereo pair, channels 1 and 2, but not 3-8

[Sphyr]

Thunder ain't exactly correct. Word clock is sample accurate timing information. When your doing a digital transfer, the source and the target have to be clocked and running at the same speed with accuracy equal to the sample rate i.e 1/48000 or 1/44100 a second (48kHz and 44.1kHz). If machines arn't clocked proberly, you get word errors. Nasty digital spikes that can be very loud and painfull. You can't transfer digitly between 2 differant sampling. The source and the targets have to be the same usally 44.1 or 48kHz. AES-EBU carries clock information on the first stereo pair, channels 1 and 2, but not 3-8

[ThunderRoadPost]

Originally posted by ThunderRoadPost:
"The clock is needed to synchronize audio data so it can be read by machines connected via AES/EBU."

That's exactly what I said, though I didn't go into too much detail so as not to confuse Mr. Superchow. If machines are not synced together via word clock they will not be able to read, nor play, the audio correctly (resulting in the problems you go on to describe).

Thanks for the input, though. http://www.audioforums.com/forums/smile.gif