Members dougbeens Posted September 12, 2004 Members Share Posted September 12, 2004 Just curious what a "word clock" or MIDI wordclock is? Link to comment Share on other sites More sharing options...
Members jchas Posted September 12, 2004 Members Share Posted September 12, 2004 All digital components use a wordclock as a timing referencefor playing back samples and other functions. When syncingdifferent digital components it's important to use one as themaster and the rest as the slave. If not, the slight differencein each devices wordclock speed can cause timing errors and other types of un-musical glitches. Link to comment Share on other sites More sharing options...
Members Boom Posted September 12, 2004 Members Share Posted September 12, 2004 It's that thing Flava Flav wears around his neck. Link to comment Share on other sites More sharing options...
Members The Audacity Works Posted September 12, 2004 Members Share Posted September 12, 2004 No such thing as MIDI wordclock, but here's my extensive blathering about regular wordclock, posted on this very forum about fifteen zillion times (oh, that sexy, sexy search button... Oooh, it's so sleek and convenient...)_____________________________ Every PCM digital audio device generates audio made up of zeroes and ones. For CD-quality audio, it generates 44,100 "clumps" of 16 zeroes and ones every second. Hence, 16-bit, 44.1k. Now if the device spits these clumps (called "words") out exactly one-44,100th of a second apart, then we're cool. If not, well... Think of it this way: If you take a film camera and shoot a horse running across a field, and if each of the 24 frames per second are exactly 1/24th of a second apart, then upon playback, the horse's gallop will look natural and fluid. If the frames aren't lined up perfectly, the horse may look a little jittery, like turn-of-the-century movies when the cameras were hand-cranked. But it gets even more complicated when you start adding extra gear into the mix. Even if the frames on your film stock are perfectly aligned, your projector has to be synced as well. It not only has to open its shutter exactly 1/24th of a second apart, but it has to open precisely when the film is set evenly within the shutter's opening (I can't remember the correct film terminology-- bear with me here, I'm an audio guy). Notice we're not talking time-based sync here, like MIDI timecode, MIDI Clock, or SMPTE-- We're talking speed-based sync. In regards to digital audio, since we're talking 1/44,100ths of a second, it's safe to call this microspeed-based sync. Remember our jittery horse? Digital audio can exhibit jitter as well. If it's bad enough, you'll end up with pops and clicks, or worse, complete dropouts or no audio at all. If it's not remarkably bad, jitter can still result in a smearing of the stereo image, some phase issues, and a pillowy-sounding bass. Every digital audio device has some amount of jitter, even if it's the only piece of gear in the chain. It can get worse when one starts connecting two or more devices digitally. Now both devices have to be clocked together. Typically S/PDIF RCA and optical connections take care of any clocking issues for you. With ADAT lightpipe or AES/EBU, you're required to select which device is the clock master and which is the slave. The slaved device will read and write its digital audio at the speed of the master's clock. Ideally, every digital audio device would sport wordclock ins and outs, which do nothing but sync (again, microspeed-based sync) two or more devices together. Unfortunately, most don't. For those that do, the most common wordclock connector is BNC. As you might expect, there are differences in the stability of different clocks. Dedicated clock generators by Apogee, Aardvark, Lucid, and others can drastically clean up audible weirdness in a rig by sending a centralized wordclock signal to every digital device in your studio (either directly via BNC or indirectly through a BNC-clocked device's ADAT lightpipe, AES/EBU, or S/PDIF output), but any sonic advantages are primarily determined by how bad your clock problems were to begin with. If you only have two devices, don't worry about it. If you have a room full of samplers, ProTools interfaces, digital mixers, DAT machines, outboard converters, and others-- all connected digitally, dedicated clock generators can save your ass. Taking advantage of wordclock doesn't have to be complicated. Say you have a PreSonus Digimax (8-channel preamp and A/D converter) connected via ADAT lightpipe to an Echo Layla24. If you slave the Layla to the Digimax via said lightpipe, it'll probably work just fine. However, if you connect a 110-ohm BNC cable from the Digimax to the Layla (and tell the Layla to slave via BNC wordclock instead of lightpipe), chances are you'll notice a slight boost in sound quality. Or... it may sound better slaving the Digimax to the Layla. Experimentation is the key. As a general rule, a dedicated A/D converter tends to offer a better-than-average clock, so making it your wordclock master is a safe bet. If you're super anal, check this out: As a test, we ran a guitar into a Line6 Pod Pro and monitored its headphone out. Its audio outputs weren't connected to anything. We ran a BNC out from an Aardvark Aardsync II wordclock generator to the back of the Pod Pro's BNC in. If we toggled the "Digital Sync" switch from internal 44/48k to external, we could definitely tell a difference. Switching to external sync sounded better, because the Aardsync was telling the Pod Pro's converters to spit out its zeroes and ones with less jitter. Hope this helps. Link to comment Share on other sites More sharing options...
Members cybermooks Posted September 13, 2004 Members Share Posted September 13, 2004 A very good explanation Audacity. You can also use the MOTU Digital Time Piece for this. Do you find any difference if you daisy chain the clock signal, i.e. if you have several devices that need to be clocked and only a few clock I/Os on your master device? Link to comment Share on other sites More sharing options...
Members GigMan Posted September 13, 2004 Members Share Posted September 13, 2004 Originally posted by Boom It's that thing Flava Flav wears around his neck. O- M - friggin G!! I just laughed so hard I almost fell out of my chair... Good one, Boom - You Canadians are pretty darn funny, aren't you?!... Link to comment Share on other sites More sharing options...
Members Boom Posted September 13, 2004 Members Share Posted September 13, 2004 Originally posted by GigMan O- M - friggin G!! I just laughed so hard I almost fell out of my chair... Good one, Boom - You Canadians are pretty darn funny, aren't you?!... I'm actually an American citizen. Perhaps the Canadian humor (or "humour" as they spell it here) is rubbing off on me. Link to comment Share on other sites More sharing options...
Members The Audacity Works Posted September 13, 2004 Members Share Posted September 13, 2004 Originally posted by cybermooks A very good explanation Audacity. You can also use the MOTU Digital Time Piece for this. Do you find any difference if you daisy chain the clock signal, i.e. if you have several devices that need to be clocked and only a few clock I/Os on your master device?You mean with BNC "T" connectors? I daisy-chain only two devices Link to comment Share on other sites More sharing options...
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