? Clocking Problem with AFIII + Apollo x8 + Apollo twin + Audient ASP 800

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philbert_s

Member
HI Team,

Somewhat complicated setup here, but stay with me.

I've got my Audient 8 channel preamp / interface connected by ADAT cable to my Apollo x8. Audient is clock source. I have the Apollo twin connected to the Apollo x8 by thunderbolt. This setup works great.

The AFIII is also connected to my MacBook by USB (so that I can use Axe-Edit), and the main analog outs are connected to the Twin.

Sometimes, I get audio glitching through the monitors. Kind of a soft crackling. I am 99% sure it is a clocking problem (because I've had it before if for some reason the apollo doesn't clock right to the Audient). The crackling goes away if I turn off the Axe. Sometimes, it doesn't happen. For example, if I am careful to power up the Axe last, sometimes I have no problem at all.

When I look under my control panel, the AFIII is available as a device for sound output. It makes me wonder if the system is somehow getting multiple clock signals and things are getting flaky. So I'm wondering if there is a way to make the USB not see the AXE as an audio interface.

Does this make sense to anyone?

Phil
 
are all devices clock sources set to right source? And i think you need also a 2nd ADAT cable from Apollo's out to Audient's in...incase it's missing. I have kind of a similar setup like yours, and i am also using digital out of Axe FX 3...no issues sice years.

My signal chain, all digital via optical/spdif/thunderbolt : Axe FX 3 -> Apollo x8p -> Apollo 8 -> Neumann KH750 Subwoofer
 
The second ADAT cable isn't needed. Everything on the apollo side is running at 44.1 glitch free otherwise. The problem only appears when the Axe is switched on, and the only connection it could be responding to is the USB. So I'm guessing what I'm hearing is a sample rate mismatch because the AFIII is trying to clock to the USB signal from the mac?

Really, I just want to use the Apollo for guitar tones / analog. I don't want it to interact digitally with the rest of the studio.

Phil
 
Thanks team. I've managed to rule out a system clocking issue. It happens even if I disconnect USB. I've got something overloading somewhere. I just can't figure out where. Will start a new thread.
 
Leaving this for posterity, in case someone else runs into this problem.

The UAD literature says that the twin will clock automatically to the x8 over thunderbolt. However, it will only do this if the x8 is not clocked to an external device (i.e. The x8 must be master).

Thus, to make the system work, the x8 is master and the asp880 must be slaved to it over a wordclock bnc cable. The twin should then slave to the x8 automagically.

We will see when my cable arrives tomorrow.

Why the twin can’t just read the clock rate off the x8 in the former instance is a mystery to me. The twin doesn’t have work clock, So no matter what it has to watch for the clock rate over the thunderbolt.

Phil
 
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