Random digital cracks with SPDIF

Armageddon

Armageddon

Member
Hello to the Fractal community !

I'm posting here to maybe have some good advices as I'm trying to figure out how to solve an annoying issue.
I'm currently recording a band and the guitarist is passing through my Axe FX 2 XL.
I'm using the SPDIF out of the Axe to the SPDIF in of my sound card (Motu 2408 MK3).
My sound card is set to 48 Khz and I'm using high quality SPDIF gold plated cables.
The sound is great (no digital mess, the card and the Axe are in sync) but, from time to time I get small cracks in the recorded sound.
It appears here and there and it looks and sound like digital junk.
Take a look at the screen capture attached. This is a close up view on a small area where those cracks appear. There are individual samples here and there out of sync.
This is simple as this and this appears at different random times on the waveform.
What I don't understand is where it is coming from and how to get rid of it.
Could it be a clock issue between the Axe and my sound card ?

Thanks for your help and suggestions.
 

Attachments

  • cracks.PNG
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OK ! I will try to change this. I think the sound card is the master indeed, I use it as the master for another digital device.
Thanks for the quick answer !
 
The manual is a bit incomplete and out of date in that section. The Axe-FX can sync to an external clock source (at SPDIF or AES input) during normal guitar playing (main input source = Input 1) with the "word clock" parameter set to SPDIF/AES.
 
I have the same digital click issue with AX8-->Scarlett 6i6 via SPDIF. I've tried everything I can think of and can't get rid of it. If I go AX8 straight to monitors there is no click.
 
The digital clicks are unrelenting. If anyone has thoughts on resolving this I'm all ears. Including changing from focusrite to something else.
 
Wigam2 said:
The digital clicks are unrelenting. If anyone has thoughts on resolving this I'm all ears. Including changing from focusrite to something else.
Click to expand...
I've been previously using Axe FX through SPDIF with focurite with no issues at all.
If the world clock is set correctly, that is.
 
The clock settings match, otherwise there would be no guitar coming through. But I'm not sure what the "world clock" is. I've seen this term a couple times, not sure if it's something different or where it would be found.
 
Wigam2 said:
The clock settings match, otherwise there would be no guitar coming through.
Click to expand...

This might not be accurate as some interfaces (including Focusrites, Saffire line at least) can monitor/record digital input without syncing, but this usually results in clicks.

When you say "the clock settings match", what are you seeing on each device? What's the clock/sync source in Focusrite mix/control software?

FreeMind meant "word clock" above, not "world clock".
 
I might have solved it. . . in the focusrite software there's a setting for "Clock source" and the options are "internal" or "S/PDIF". It was set to internal. I switched it to S/PDIF and the clicks seem to have disappeared.

Fingers crossed!
 
My recollection is that you need to toggle the master/slave relationship based on what you are doing.

Recording from the Axe : Axe master, interface slave
Re-amping back to the Axe : interface master, Axe slave
 
Wigam2 said:
I might have solved it. . . in the focusrite software there's a setting for "Clock source" and the options are "internal" or "S/PDIF". It was set to internal. I switched it to S/PDIF and the clicks seem to have disappeared.

Fingers crossed!
Click to expand...
That's what we've been trying to tell you from the beginning. In any synchronous digital transmission there needs to be a shared clock. In the case of SPDIF the clock can be derived from the data stream. This means you need one device to be a master (internal clock) and the other slave (derived from data stream).
 
Thick skull I guess. . . what I lack in knowledge I make up for with persistence. :D. I have an AX8 and "word clock" was unfamiliar.

I appreciate the input as it appears to be resolved!
 
Those are the only two options, on the AXE either SPDIF/AES IN or AUTO.
The Focusrite is either Internal or SPDIF.

When trying to set the Focusrite to SPDIF (slave) it switches to 44.1 and will not lock to the AXE which is set to AUTO.
 
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