adat and syncing effect on sound?

[scopus]

hey im new to using adat and recorded a bunch of material not synced between my rme interface and external instrument. Both were set to master. Only recently learned that the external should be set to slave and only now interface displays sync. The recorded material sounds ok but im worried perhaps i could have gotten better quality if they were synced ? so thinking about rerecording everything but itll be a lot of work so need to know if will be any benefit at all doing so. what does syncing/having the external as slave do exactly and how does it effect the sound?
thanks

 

[miroslav]

Are you talking about the digital clock sync...and which is master which is slave...?

Each digital device has it's own internal clock...and if they are all set to the same sampling rate, in theory, everything should be in time.
However, there is always some very minor clock drift between devices...so usually one is set to be the master clock, and the other one follows it (master/slave).

If you had them both set as master, they were on their own internal clocks. If there was significant drift...you could get digital jitter in the transfer of digital data from one device to the other...but it would have to be really significant to be audible. If everything sounds good to you, move on...and next time just set one to be the master.

 

[mixsit]

I'm curious about what you're useing;

between my rme interface and external instrument.

Like a digital keyboard ourput perhaps.
Anyway, what I've only found with clock problems is manifests as clicks in the audio. And it's very obvious, easy to hear.

 

[scopus]

Are you talking about the digital clock sync...and which is master which is slave...?

Each digital device has it's own internal clock...and if they are all set to the same sampling rate, in theory, everything should be in time.
However, there is always some very minor clock drift between devices...so usually one is set to be the master clock, and the other one follows it (master/slave).

If you had them both set as master, they were on their own internal clocks. If there was significant drift...you could get digital jitter in the transfer of digital data from one device to the other...but it would have to be really significant to be audible. If everything sounds good to you, move on...and next time just set one to be the master.

yes clock mode of both my rme interface and external device. Both had their internal clocks set to master, same 44.1 sample rate, and werent synced during all the recording. but if you say jitter would have to be significant to cause any noticeable effect on the recording than ill move on. Playing back the audio i dont hear any noticible artifacts or anything. surprised dont hear any clicks/pops as i recorded quite a bit of audio.Did i just get lucky? if i wont have any audible benefit regarding quality rerecording everything happy to move on
thanks

 

[scopus]

I'm curious about what you're useing;

Like a digital keyboard ourput perhaps.
Anyway, what I've only found with clock problems is manifests as clicks in the audio. And it's very obvious, easy to hear.

actually hooked up with adat 2 audio interfaces via 2 computers. my main daw computer with the rme and a secondary computer with different (sonnicore) pci interface recording its synths that use its interface software and dsp.

Playing back the audio dont notice any clicks or anything, guess im in the clear and wont have any benefit rerecording ?

thanks

 

[mixsit]

"Did i just get lucky?"
Interesting ..and curious how you could have. (Can't imagine why, or how it could have.
What's the instrument BTW?

 

[mixsit]

actually hooked up with adat 2 audio interfaces via 2 computers. my main daw computer with the rme and a secondary computer with different (sonnicore) pci interface recording its synths that use its interface software and dsp.

Playing back the audio dont notice any clicks or anything, guess im in the clear and wont have any benefit rerecording ?

thanks

Thanks.

 

[keith.rogers]

So you recorded on two separate devices and they sync'd Ok? Or am I misreading this?

The clocks (these days) are so precise that I've never noticed the drift in shorter pieces. Maybe around 1/2 hour or so, but nothing that isn't correctable anymore.

If you want to sync two independent devices, one of them must have the ability to send just a clock signal and the other the ability to just accept it.

If you're connecting an ADAT device through an interface, e.g., with an optical cable, there's some chance that the default configuration may be doing what you should have configured, i.e., the ADAT acted as the master clock, even though you didn't do that beforehand. Or, yes, "you got lucky." Something to practice configuring properly so less dependency on luck next time!

 

[miroslav]

The clocks (these days) are so precise that I've never noticed the drift in shorter pieces. Maybe around 1/2 hour or so, but nothing that isn't correctable anymore.

I think maybe you are confusing timeline synchronization (actual time - SMPTE/MTC)...VS...digital clocking of the data transfer (making sure the samples line up from one device to the other relative to their selected sample rate.

There won't be any real "drift" over time between tracks with digital clock issues, like something you can adjust with time-alignment...etc.
It's just data transfer jitter, which might be heard as pop/click noise, or maybe a sense of audio "smearing" of a stereo image...etc.
You can have clock jitter and not notice it...or it maybe quite noticeable. The audio gets a grainy quality to it.

 

[ashcat_lt]

If the two devices recorded their respective tracks seperately, both as masters, to their own internal storage, and you then make one slave to the other for playback, you won't get noise, but you may have one of them playing back at a rate different from what it recorded at, which will cause both time and pitch change exactly like varispeed on analog tape.* It's when you try to play one through the other (digitally) with both trying to be master that you end up with clicks and pops and flangey craziness.



Edit - *This is also exactly what we'd expect if we were to directly import the data from one to another and then play back just from the one. Unless one of the clocks is severely fucked, or you have super accurate perfect pitch and timing, or it goes for days on end, you'll probably not notice the difference.

 

[miroslav]

If the two devices recorded their respective tracks seperately, both as masters, to their own internal storage, and you then make one slave to the other for playback, you won't get noise, but you may have one of them playing back at a rate different from what it recorded at, which will cause both time and pitch change exactly like varispeed on analog tape.* It's when you try to play one through the other (digitally) with both trying to be master that you end up with clicks and pops and flangey craziness.

OK...but I don't think that has anything to do with the OP's situation.

He's outputting his ADAT tracks to an RME interface...and forgot to set one as the master clock.
I don't believe there was any mention of two recording devices used for playback...or that different sampling rates were used.

 

[scopus]

It's just data transfer jitter, which might be heard as pop/click noise, or maybe a sense of audio "smearing" of a stereo image...etc.
You can have clock jitter and not notice it...or it maybe quite noticeable. The audio gets a grainy quality to it.

This what was worried about, that it affects the sound beyond clicks/pops. Dont want any smearing/grain or loss of resolution in recordings which i might be harder to notice. Guess should rerecord. Thanks

 

[rob aylestone]

Re-record? Why? If there's no problem you can hear, then all is fine and dandy. It's been a long while now, but ADAT needed it's own sync to allow multiple recorders to actually go into record. The first one would roll, then the others would lock to it, then go into record. If they couldn't sync, the record lights would not come on. Word clock sync was the totally separate system that allows every recorder and other device to use the same generator for the digital stream. With any system that has to lock up, it is bad to put the left and right of a pair on different machines because as the mechanical machines are controlled to keep the in sync, there are small timing errors that cause phasing issues. Keeping the paired tracks on the same machine makes it work properly. If your tracks don't glitch, there's no point re-recording. The time differences here are microscopic compared with a musicians timing.

There will be no difference in the sound at all - if one machine records as 44.1000001 and the other at 44.09999999KHz that isn't an error, its just life. Word clock makes them all the same. You will not hear this. Remember that ADAT has a really good error compensation system to deal with tiny gaps in the digital stream that are totally unnoticeable until they are so big the machine mutes.

 

[miroslav]

This what was worried about, that it affects the sound beyond clicks/pops. Dont want any smearing/grain or loss of resolution in recordings which i might be harder to notice. Guess should rerecord. Thanks

Again...listen to you source tracks directly off the ADAT and listen to the transferred tracks...if you're not hearing any obvious issues, why re-record.
I think the "smearing" and graininess would be more evident if you had transferred a finished stereo mix, where the Left/Right imaging needs to be solid, and where poor clock sync and jitter might be a real issue. With the individual tracks, I wouldn't think so. I mean, are you recording real delicate stuff...like stereo miked acoustic guitar or a real piano..etc...where even the most subtle sonic nuances would need to be perfect and crystal clear...?

 

[mixsit]

actually hooked up with adat 2 audio interfaces via 2 computers. my main daw computer with the rme and a secondary computer with different (sonnicore) pci interface recording its synths that use its interface software and dsp. ...

I'm still not clear what this means.

Two seperate I/F's and computers
-one a DAW and the other running synths?
Does the DAW just record the software synths' stream via ADAT.. from the other computer's sound card.. or?
IDK I'm guessing here..

 

[scopus]

since you guys say the difference will be microscopic not noticble than ill just leave it as is. thanks

 

[scopus]

I'm still not clear what this means.

Two seperate I/F's and computers
-one a DAW and the other running synths?
Does the DAW just record the software synths' stream via ADAT.. from the other computer's sound card.. or?
IDK I'm guessing here..

yes one computer running daw with the rme receiving adat from a second computers interface which has synths/fx that run on it

 

[mixsit]

yes one computer running daw with the rme receiving adat from a second computers interface which has synths/fx that run on it

Thanks Scopus. Now I just need that to 'peculate some to get the ramifications to poke out the other side. :>) For my own purposes at least (learning and understanding..), I doubt it was 'luck, just not sure yet how it worked out ok. Probably missing something basic re the 'master/slave data flow scenario -which I thought I knew!

 

[miroslav]

Oh...now I get it. I initialy understood it was an actual ADAT recorder, feeding an RME interface.

OK...so then, the question...why do you need to apply synths/fx in that manner...from a second computer?
I mean...it can be done... but why not record the live/acoustic instruments & vocals right to the RME computer, and then add the synths/FX there, on that computer...?...why do you have to use two computers?

 

[mixsit]

since you guys say the difference will be microscopic not noticble than ill just leave it as is. thanks

A digital stream is either solid (in sync) or not. However.. the exception being the receiving end's re-clocking quality.
And RME's is probably among the best.
That could be the answer.