S/PDIF What determines Master/Slave?

[mwd]

I usually just fire my Apollo Quad to jam with my XL as I like the console function amongst other things. I'm hooked up via S/PDIF and the clock is set internal on the Apollo.

I got a new AX8 and also hooked up S/PDIF. The sound was a bit fizzy and I read in another thread to hook up audio interface as external with the AX8 so I did. I think it may have helped my issue but it brought up the question.

What determines whether you use 'internal' or 'external' on your audio interface when using S/PDIF with Fractal products? Or any products for that matter.

 

[Bakerman]

Sometimes there will only be one option for sync. With a 1-way SPDIF connection (like AX8 to interface) the upstream device (AX8) has to be master.

With the Axe-FX during normal use (playing guitar directly into Axe-FX) you have the option of using SPDIF/AES input as clock source. When using SPDIF/AES as main input source the Axe operates in slave mode, requiring the other device to be clock source.