Topic: Clocking Issues

I'm running a 2016 trash can Mac Pro, Pro Tools 12.5, an RME Fireface UCX, and an 11 Rack running SPIDF to the Fireface. The Fireface is connected via USB to the Mac Pro. I'm streaming audio off a roughly 10-year-old Lacie hard disk. The Mac Pro is on El Capitan 10.11.6. I'm having issues with popping noises in the audio in my tracks. I believe it is a clocking issue. First off, is there any benefit to using the clock in the UCX as the master instead of using the clock in my computer? My computer says that the clock setting is "default." Does that mean the computer's clock is the master one? If so, what setting should the fireface's clock be set to? Right now it is set to "internal." Also, do the clock settings for The Pro Tools aggregate i/o matter when running the Fireface UCX? Any info would be greatly appreciated. Thanks in advance,

                                                     -Jack

2 (edited by ramses 2017-01-24 07:41:24)

Re: Clocking Issues

UCX should be master with clock source set to internal. It has the better quality clock, see RME "Steadyclock" ...

There can be only 1 master, the other devices that are connected digitally (directly or cascaded) to the UCX need to be slave.

So for this to work the 11 Rack needs to be configured as "slave". I heard i.e. Kemper Amp can only act as clock master when being digitally connected to a recording interface. You need to look whether this is the case for 11 Rack as well.
If 11rack can only act as master then you
- either need to set UCX to "slave"
- or connect 11 rack not digitally, use analog output on 11Rack and analog inputs on UCX

The computer itself does not need to be configured as master or slave. The RME device is your main instance.
You need to set clock to master or slave only for devices that you connect to the RME recording interface.

Or does your Apple have a digital interface of its own that you are using ? The usual case is at least on Windows to best disable all audio interfaces of the computers mainboard.

Another thing .. if I have clock related problems, then the clocks drifted so much, that after minutes the sound was completely distorted. Maybe there are other problems.

What happens i.e. if you disconnect 11 Rack from your Apple ? Still this noise ?
What happens if you disconnect the external Harddisk ?

Keep everything else disconnected from USB or Firewire and try all other USB ports of your Apple computer ?
Still pops when playing sound ?

BR Ramses - UFX III, 12Mic, XTC, ADI-2 Pro FS R BE, RayDAT, X10SRi-F, E5-1680v4, Win10Pro22H2, Cub13

Re: Clocking Issues

Ok I have the 11 Rack set to be slave now. It was set to be on its own internal clock before. That may cure the problem with the popping noises in the guitar tracks. The RME clock setting is on "internal," now (same as it was before). I am unsure if my Mac Pro has its own interface. It is a totally stock unit that I bought last February in case anyone knows offhand. I'll call Apple this evening and ask them. I did hear similar popping noises in the vocal tracks though too. I was plugging the vocal microphone (Rode NT1A) into the 2nd XLR input on the UCX, with the 11 Rack turned off, so I wouldn't think that the 11 Rack would affect the system at that point.

Re: Clocking Issues

Ok I got in touch with Apple customer support and the woman on the phone was very unhelpful. She could not answer whether or not my computer has its own internal interface. She did seem to think that when my computer is on its "default," setting that it thinks it is the master clock. Unfortunately there is no other option but "default," for this setting. For the time being at least I think I'm going to just use my computer's clock as the master one. Is that possible? To do that do I just Set my Fireface's clock to "optical," instead of "internal," in the "Fireface USB Settings," program on my computer? As I was saying, the popping noises seem to happen even without the 11 Rack connected.

Re: Clocking Issues

Can you provide a screenshot, where you see this "default" setting ?

BR Ramses - UFX III, 12Mic, XTC, ADI-2 Pro FS R BE, RayDAT, X10SRi-F, E5-1680v4, Win10Pro22H2, Cub13

Re: Clocking Issues

There's no audio clock in your Mac Pro that's in play. I have no idea where you see this setting. OSX's Core Audio clock is always hidden from the user, because it is only used for the internal audio ports.

Maybe you're looking at RME's settings control panel?

The only clocks involved are the one in the UCX and in the 11 rack. I don't know the 11 rack, so I can't really comment on that.

And I don't think this is a clock problem, but a Protools problem. You'll need to hunt down that pesky extension PT installs, as it wrecks all other audio interfaces. Unfortunately, Avid has the habit of changing the name. Instructions:

- Open the Finder and locate the following folder: Macintosh HD > Library > Audio > Plug-Ins > HAL
- Move the “Avid CoreAudio.plugin” outside of this folder (e.g. to the Desktop).
- Type in the admin password when prompted.
- Restart your Mac.

Check if the crackling is gone.

MB Pro - 2 X FireFace 400, FF800 & DigiFace USB
ADAT gear: Korg, Behri, Fostex, Alesis...

Re: Clocking Issues

cyrano wrote:

There's no audio clock in your Mac Pro that's in play. I have no idea where you see this setting. OSX's Core Audio clock is always hidden from the user, because it is only used for the internal audio ports.

Maybe you're looking at RME's settings control panel?

The only clocks involved are the one in the UCX and in the 11 rack. I don't know the 11 rack, so I can't really comment on that.

And I don't think this is a clock problem, but a Protools problem. You'll need to hunt down that pesky extension PT installs, as it wrecks all other audio interfaces. Unfortunately, Avid has the habit of changing the name. Instructions:

- Open the Finder and locate the following folder: Macintosh HD > Library > Audio > Plug-Ins > HAL
- Move the “Avid CoreAudio.plugin” outside of this folder (e.g. to the Desktop).
- Type in the admin password when prompted.
- Restart your Mac.

Check if the crackling is gone.

Ok interesting. I was under the impression from the RME manual that the UCX did need to be sync'ed to the computer's clock. I'll give this a shot though. Thanks!

Re: Clocking Issues

The RME needs to be synced to the computer, but it is always master clock, for audio. At least, that's how I understand it. And if I'm wrong, I'm counting on Mattias to set me right big_smile

When you have multiple devices, you need to choose a master and some slaves. Unless one of these devices can't be switched, like your Eleven rack, it seems.

MB Pro - 2 X FireFace 400, FF800 & DigiFace USB
ADAT gear: Korg, Behri, Fostex, Alesis...