D
Dr Unedumacated
New member
I've seen alot of stuff about SMPTE, studio clocks, and synchronization, but what do they actually synchronize? Do they synchronize the ADAT machines or what? Are they all the same thing?
DDev
New member
OK, lets see....the poll has nothing to do with the topic....
Anyway, to provide a quickie answer to the question. I don't know a lot about SMPTE but it is usually referenced in relation to synchronizing audio gear with video gear, I think.
As far as studio clocks go, they provide a common source to synchronize multiple digital audio devices together in a studio. Without a common clock each piece of gear will operate on its own internal clock and there may be variations that can cause audible distortion to the digital audio when several pieces of gear are used together.
Hope this helps,
Darryl.....
Anyway, to provide a quickie answer to the question. I don't know a lot about SMPTE but it is usually referenced in relation to synchronizing audio gear with video gear, I think.
As far as studio clocks go, they provide a common source to synchronize multiple digital audio devices together in a studio. Without a common clock each piece of gear will operate on its own internal clock and there may be variations that can cause audible distortion to the digital audio when several pieces of gear are used together.
Hope this helps,
Darryl.....
K
kilowatt
New member
Sync is everything
There's no way I can answer /all/ that right here, but here's a basic guide:
There are two types of sync. Real-time, and Tempo-based.
First the real time:
Realtime sync carries absolute time-reference from one thing to another. An example of a real time position is 01:34:20:02, which is expressed in hours, minutes, seconds, frames.
SMPTE LTC (linear time code?) is the audio form of real-time sync. That is, SMPTE travels via audio equipment. You can record SMPTE on tape, and you can cable it just like any other audio signal. You can even hear it - sounds like a turkey running around or something.
MTC is MIDI Time Code. Its basically the same thing as above, only over MIDI cables. This is a popular way of getting SMPTE LTC into computers (you just need a PPS2 or similar to convert the media).
VITC, Vertical Interlaced Time Code, is real-time sync over video. I don't know much about this.
Now for the Tempo-based:
Tempo-based sync is used mainly for syncing MIDI to Audio. An example of a tempo-based location would be something like Bar 10, beat 4, quarter-note-part 22. In order to sync with a real-time device, you need either a computer, or an MPC studio-edition (I think), which has been made aware of the song's start time, and tempo.
FSK, Frequency-Shift Keying. This isn't used much anymore, mainly because of how popular computers in studios are. But here's what it is. Its tempo-based sync over audio. If you had a MIDI sequencer in the studio, and you wanted it to play back with your tape, in sync, you just stripe FSK down on the tape, convert it to MIDI (with a PPS2 or similar), and you're done. You can record it on tape, and move it around your studio with regular audio cables. Sounds a lot like SMPTE.
Midi Clock is the MIDI form of Tempo-based sync. Lots of devices accept and understand Midi clock.
The thing is though, a computer provides so much flexibility in changing real-time sync into tempo-based sync, that these tempo-based syncs are rarely used alone now. Studios without a computer, however, probably use them frequently.
I guess we might as well go over actual studio clocks now, as that was the topic of your post.
As DDev said, studio clocks are used to generate a common 'pulse' for digital gear. Imagine this, you have a DAT player with AES/EBU out, connected into a cd recorder, with AES/EBU. If the two clocks are off slightly (and at 44,100 samples per second, you can bet they will be a little different), data will get sent, when the other device isn't looking for it. And then you get these drop outs, and similar. Its very bad sounding
.
So what people will do, is either patch "word clock" between the devices to keep everything in sync (and set one device to 'slave' to the other, usually 'ext' for external), or use the timing within the incoming digital signal.
This works great, but then you have situations with so much gear, it would be impossible to sync them all up to one dat recorder, due to the signal loss of 'splitting' word clock 20 times or so. The average digital studio has so much gear, it would be a nightmare.
So, they have these things called studio clocks, which provide stable, distributed clock pulses to everything. The better the clock source, the lower the jitter (variations in sample rate, which I think would translate into unstable pitch on playback). Seemingly bad converters might sound half way decent with a better clock source.
There's also machine sync, which is used to control the location and transport of two or more machines. For example, you want the dat recorder to start recording the moment you hit 'play' in protools. This can be either over midi, (MMC - Midi Machine Control), 9-pin serial, or something completely strange, like the 15-pin connector on the back of an Otari tape machine.
Sync is really important to understand, in my opinion, because it opens up possibilities that would otherwise be, well, impossible.
There's no way I can answer /all/ that right here, but here's a basic guide:
There are two types of sync. Real-time, and Tempo-based.
First the real time:
Realtime sync carries absolute time-reference from one thing to another. An example of a real time position is 01:34:20:02, which is expressed in hours, minutes, seconds, frames.
SMPTE LTC (linear time code?) is the audio form of real-time sync. That is, SMPTE travels via audio equipment. You can record SMPTE on tape, and you can cable it just like any other audio signal. You can even hear it - sounds like a turkey running around or something.
MTC is MIDI Time Code. Its basically the same thing as above, only over MIDI cables. This is a popular way of getting SMPTE LTC into computers (you just need a PPS2 or similar to convert the media).
VITC, Vertical Interlaced Time Code, is real-time sync over video. I don't know much about this.
Now for the Tempo-based:
Tempo-based sync is used mainly for syncing MIDI to Audio. An example of a tempo-based location would be something like Bar 10, beat 4, quarter-note-part 22. In order to sync with a real-time device, you need either a computer, or an MPC studio-edition (I think), which has been made aware of the song's start time, and tempo.
FSK, Frequency-Shift Keying. This isn't used much anymore, mainly because of how popular computers in studios are. But here's what it is. Its tempo-based sync over audio. If you had a MIDI sequencer in the studio, and you wanted it to play back with your tape, in sync, you just stripe FSK down on the tape, convert it to MIDI (with a PPS2 or similar), and you're done. You can record it on tape, and move it around your studio with regular audio cables. Sounds a lot like SMPTE.
Midi Clock is the MIDI form of Tempo-based sync. Lots of devices accept and understand Midi clock.
The thing is though, a computer provides so much flexibility in changing real-time sync into tempo-based sync, that these tempo-based syncs are rarely used alone now. Studios without a computer, however, probably use them frequently.
I guess we might as well go over actual studio clocks now, as that was the topic of your post.
As DDev said, studio clocks are used to generate a common 'pulse' for digital gear. Imagine this, you have a DAT player with AES/EBU out, connected into a cd recorder, with AES/EBU. If the two clocks are off slightly (and at 44,100 samples per second, you can bet they will be a little different), data will get sent, when the other device isn't looking for it. And then you get these drop outs, and similar. Its very bad sounding
.So what people will do, is either patch "word clock" between the devices to keep everything in sync (and set one device to 'slave' to the other, usually 'ext' for external), or use the timing within the incoming digital signal.
This works great, but then you have situations with so much gear, it would be impossible to sync them all up to one dat recorder, due to the signal loss of 'splitting' word clock 20 times or so. The average digital studio has so much gear, it would be a nightmare.
So, they have these things called studio clocks, which provide stable, distributed clock pulses to everything. The better the clock source, the lower the jitter (variations in sample rate, which I think would translate into unstable pitch on playback). Seemingly bad converters might sound half way decent with a better clock source.
There's also machine sync, which is used to control the location and transport of two or more machines. For example, you want the dat recorder to start recording the moment you hit 'play' in protools. This can be either over midi, (MMC - Midi Machine Control), 9-pin serial, or something completely strange, like the 15-pin connector on the back of an Otari tape machine.
Sync is really important to understand, in my opinion, because it opens up possibilities that would otherwise be, well, impossible.
Track Rat
Just Your Average Sized Member
Syncing transports is one thing but if you're refering to Master Clock, it can be extremly important, even if you only have one digital device (a digital recorder that is equiped with an external Word Clock input). A high quality, low jitter clock can improve audio performance over the stock clock that comes inside a lot of digtal gear. I use a Lucid GenX6 to clock my HD24, MOTU 2408 mkII and anything else in the studio that's digital and has an external Word Clock input.
G
GamezBond
New member
thanks man
B
BRDTS
Member
Here's my totally weird setup regarding clock. This has evolved over many years and was definitely not planned in the beginning.
Nuendo with 2 Laylas inside. 1 set to master clock. Word clock out to 2nd card, wordclock out of that to Digital Timepiece clock . DT feeds clock to two adat machines. Also feeds mtc/spdif clock to a stack of old Fostex D90-s for sync. Also feeds smpte to a Midiizer which feeds and syncs an old Tascam msr24 and Tascam 8516B...which also feeds an ats500 synchronizer which syncs an old Tascam TSr8, which also feeds an mtc signal to a 2nd pc with Acid, which also feeds a 3rd pc with Vstack. All of this stuff basically fed from the DT after it receives master clock from the Laylas in the Nuendo pc. I figure that makes for about 2 bazillion tracks of analog and digital.
Do I ever actually use everything at the same time? I did a couple of years ago to see if it all worked. It did. Perfectly flawless sync. But do I routinely use it? No. Would've been real nice to have these inventions in 1972 when I really needed the track count.
Nuendo with 2 Laylas inside. 1 set to master clock. Word clock out to 2nd card, wordclock out of that to Digital Timepiece clock . DT feeds clock to two adat machines. Also feeds mtc/spdif clock to a stack of old Fostex D90-s for sync. Also feeds smpte to a Midiizer which feeds and syncs an old Tascam msr24 and Tascam 8516B...which also feeds an ats500 synchronizer which syncs an old Tascam TSr8, which also feeds an mtc signal to a 2nd pc with Acid, which also feeds a 3rd pc with Vstack. All of this stuff basically fed from the DT after it receives master clock from the Laylas in the Nuendo pc. I figure that makes for about 2 bazillion tracks of analog and digital.
Do I ever actually use everything at the same time? I did a couple of years ago to see if it all worked. It did. Perfectly flawless sync. But do I routinely use it? No. Would've been real nice to have these inventions in 1972 when I really needed the track count.
sjoko2
New member
What time is it??? 
Track Rat
Just Your Average Sized Member
sjoko! good to see you in these parts. What's up man?
Blue Bear Sound
New member
Sjoko!!! Where ya been, mon?!?!sjoko2 said:What time is it???
M
musicman23
New member
I'm trying to find the answer : My Pro Tools session shows me this message
"Problem detected with audio clock. Check that your clock source and sample rate are correct. " What do I have to do ? I cannot play the session.
Thank you
"Problem detected with audio clock. Check that your clock source and sample rate are correct. " What do I have to do ? I cannot play the session.
Thank you
Similar threads
- astokesmusic
- Studio Building & Acoustic Treatment
- cncjerry
- Alesis Forum
- rob aylestone
- Recording Techniques