Word clock

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Nick The Man

Nick The Man

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what is the purpose of a word clock .. is it something i can buy and hook up to things ... where why when do i use one and for what reason
 
If im understandin u correctly its a syncing option u can use in software.
 
misscc803 said:
If im understandin u correctly its a syncing option u can use in software.
Click to expand...

is that what its used for

sync??


ive also never understood what sync is used for??
 
Syncing is done to keep everything in track. Like say you have a keyboard and u made a beat on it and u need to record it into the computer(software). You will need to track out each sound u used. So lets say u used 10 sounds(tracks). Now using MIDI u can now record each sound and they all be fittin properly. Cause if u have a kick come in at 3 secs and a snare at 5 secs the only way to keep it in that alignment is to have somethin to start each track from the same location, the beginning. Hope that helped. By the way are u needin to do some of this or somethin?
 
misscc803 said:
Syncing is done to keep everything in track. Like say you have a keyboard and u made a beat on it and u need to record it into the computer(software). You will need to track out each sound u used. So lets say u used 10 sounds(tracks). Now using MIDI u can now record each sound and they all be fittin properly. Cause if u have a kick come in at 3 secs and a snare at 5 secs the only way to keep it in that alignment is to have somethin to start each track from the same location, the beginning. Hope that helped. By the way are u needin to do some of this or somethin?
Click to expand...

nope just asking some unanswered questions of mine thank you ioll fins anpother to ask when i think of one
 
A word clock is used to synchronise different digital devices.

Say you've got an outbaord AD converter feeding your computer.
What is sent from the AD converter to the computer is just a series of 0s and 1s (bits-basic binary stuff there). Each digital "word" will be made up of 16 or 24 bits (depending on the bit depth you're recording at).
However, there isn't any way for the copmuter to know which bit comes where in the "word".
What a word clock does is act as a kind of "metronome" for digital devices. It synchronises the computer and the AD converter, so the comptuer knows which bit is the first, the second, and so on.

This becomes important when you have more than two bits of kit.
Say, for example, you've got 3 eight-way convters feeding a single 24-track recorder. Whilst it is possible for each converter to tell the 24-track where it's up to, if the three converters are out of synch with each other, then 24-tracker will get confused and will start recording the wrong bits in the wrong places, resulting in digital noise.

Some signals (like ADAT lightpipe) contain a clocking signal, however this will only work between 2 devices. If yo uhave 3 or more devices, you need a way to synchronise them.
 
cpl_crud said:
A word clock is used to synchronise different digital devices.

Say you've got an outbaord AD converter feeding your computer.
What is sent from the AD converter to the computer is just a series of 0s and 1s (bits-basic binary stuff there). Each digital "word" will be made up of 16 or 24 bits (depending on the bit depth you're recording at).
However, there isn't any way for the copmuter to know which bit comes where in the "word".
What a word clock does is act as a kind of "metronome" for digital devices. It synchronises the computer and the AD converter, so the comptuer knows which bit is the first, the second, and so on.

This becomes important when you have more than two bits of kit.
Say, for example, you've got 3 eight-way convters feeding a single 24-track recorder. Whilst it is possible for each converter to tell the 24-track where it's up to, if the three converters are out of synch with each other, then 24-tracker will get confused and will start recording the wrong bits in the wrong places, resulting in digital noise.

Some signals (like ADAT lightpipe) contain a clocking signal, however this will only work between 2 devices. If yo uhave 3 or more devices, you need a way to synchronise them.
Click to expand...


Thanks i jus gave him the Elementry version while u gave him the College Version. LOL.
 
misscc803 said:
Syncing is done to keep everything in track. Like say you have a keyboard and u made a beat on it and u need to record it into the computer(software). You will need to track out each sound u used. So lets say u used 10 sounds(tracks). Now using MIDI u can now record each sound and they all be fittin properly. Cause if u have a kick come in at 3 secs and a snare at 5 secs the only way to keep it in that alignment is to have somethin to start each track from the same location, the beginning. Hope that helped. By the way are u needin to do some of this or somethin?
Click to expand...

What you're reffering to there is MIDI timecode, or SMTPE, in which you can control various bits of equipment to come in at various times.
It's used not only with sequencers/synths, but recorders, software, camera gear etc.
However, it does not have the resolution to control digital audio. A Word Clock "beats" 48,000 times a second, whereas a SMTPE or MIDI clock will beat at about 24-30 times a second (from memory- it may be more, but certainly not high enough for a digital audio stream).

SMTPE is what most control surfaces use to control software, although USB/Firewire is starting to take a hold.
 
cpl_crud said:
What you're reffering to there is MIDI timecode, or SMTPE, in which you can control various bits of equipment to come in at various times.
It's used not only with sequencers/synths, but recorders, software, camera gear etc.
However, it does not have the resolution to control digital audio. A Word Clock "beats" 48,000 times a second, whereas a SMTPE or MIDI clock will beat at about 24-30 times a second (from memory- it may be more, but certainly not high enough for a digital audio stream).

SMTPE is what most control surfaces use to control software, although USB/Firewire is starting to take a hold.
Click to expand...

Thanks for clearing that up but i was on da right track at least. World Clock isnt popular here on my end but MTC and SMTPE def iz.
 
Here is a defenition i found:"Word Clock Sync: This is a different beast altogether. Its the clock source used by your audio interface to sync sample "words". It has nothing to do with timecode, and has everything to do with the smooth flow of digital audio between digital devices." Also check the link below for more info on MIDI and time codes.

http://www.tweakheadz.com/sync_mmc_mtc_smpte.htm
 
yeah alright fellas i think i got it thanks alot i guess ill have to think of more questions


i dont think i will be using the word clock feature for some time

all i got is my buses feeding into the interface then to the computer ... pretty direct

thanks again
 
Nick The Man said:
what is the purpose of a word clock .. is it something i can buy and hook up to things ... where why when do i use one and for what reason
Click to expand...

The more detailed explanation....

Every digital audio device contains (deep within it) a clock. If you set an audio interface to 44.1 kHz, for example, that clock generates a signal 44,100 times a second to tell the analog-to-digital converter (ADC) to take a sample of the audio.

The problem with clocks is that they are, by their very nature, relatively imprecise devices. Many are based on a crystal design, which takes advantage of the piezoelectric effect to cause a particular frequency to be generated in the presence of electricity. You'll see others that are transistor-based, and there are probably other designs that I'm not thinking of at the moment.

In any case, these clocks beat at a fairly constant rate, but that rate will fluctuate if voltage or temperature are not constant. If a circuit is designed well, you can control voltage fairly well, but temperature is a problem that really has no solution. Thus, no matter how a clock is designed, two clocks will always beat at a slightly different frequency. If you're willing to spend enough money on the design, you might get two clocks pretty close, but not exact.

The result is that if you take audio input from two different audio interfaces with two different clocks, one might sample 441,002 samples in ten seconds, while the other might sample 440,998 samples, while the ideal is 441,000. A very slight error, but an error nonetheless. Over a sufficiently long period of time, this error will accumulate, and if you recorded for an hour, that would be a difference of 1440 samples. That's about 1/30th of a second---enough to notice audibly.

That deviation of 4 samples every ten seconds is relatively small. It's not at all uncommon to drift by as much as 0.1 seconds in under 10 minutes. At that rate, an hour long recording would be off by the better part of a second. Occasionally, you'll even find really lousy cards that drift by hundreds of milliseconds per minute. That particular card would drift over 8 seconds an hour from "truth".... :D

To prevent this problem, quality audio interfaces usually provide some means to synchronize to an external clock source. For the most part, musicians use one audio interface as the "master" device and the other device as a "slave". In this way, one device uses the clock signal from the other device to basically repeatedly kick its own clock backwards or forwards slightly so that the clocks stay in time. (For the curious, look up phase locked loop.)

There are three common mechanisms to do this: Word Clock, S/PDIF, and AES/EBU.

The first, Word Clock, is the simplest form, as it is basically just a clock signal sent across the wire, AFAIK. Most devices support this, though there are notable exceptions (e.g. the FirePod).

The second, S/PDIF, is a means of transferring digital audio from one interface to another. Since the digital samples are being sent at the sampling rate of the first device, the second device must make its clock match the rate of the first device in order to interpret that data. It does this by extracting the timing information from the digital data stream itself. This is somewhat more involved than synchronizing to a word clock, and is thus probably slightly more prone to jitter, but it still gets the job done.

The third, AES/EBU, is basically the same thing as S/PDIF, only it is a balanced (differential, dual-ended) design instead of an unbalanced (single-ended) design. By using a balanced signal, it can be sent across longer distances without worrying about cable impedance as much. (S/PDIF is only recommended up to about 15m, while AES/EBU has been used at up to 300m.)

With the exception of the physical layer, S/PDIF and AES/EBU are nearly identical, though slight variations in implementation of the spec can cause some incompatibilities when trying to make an S/PDIF device talk to an AES/EBU device or vice-versa. Click here for more info.
 
ADAT Lightpipe also carries a clocking signal, so units connected by lightpipe will be using the same clock, just like S/PDIF
 
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