Popping/Crackling/Clicking Noise with no session open

[RobMacfarlane]

Hello All,

Apologies if this is not the correct forum for this question, but this problem has been hounding me for days now, and I have found no reliable way of sorting it.

Upon opening Pro Tools, even as it loads, the speakers output a horrible crackling noise that sounds very similar to a clocking issue. None of the lights on the front of the 192 show any audio leaving a particular output, yet the input meter on my monitor controller shows quite loud clicks and crackles. On opening the Avid CoreAudio manager, the same sound will be produced - again, no metering on the output of the 192, but plenty on the input of my monitor controller.

This will continue until the system is rebooted a varying number of magic times, when the problem will suddenly disappear. We can then use PT the whole day without an issue, and the problem will not re-occur until a few days later sometimes, the next morning others. Digitest runs with no issues.

Below I've posted as much info as I can find from System Profiler, but the quick layman's is that I'm running PT10 HD (TDM) on a Mac Pro OSX Lion, with a Magma Chassis holding one HD Core and two HD Accel, with a Digi 192 (Blue).

SYSTEM INFO:

Model Name: Mac Pro
Model Identifier: MacPro5,1
Processor Name: 6-Core Intel Xeon
Processor Speed: 2.93 GHz
Number of Processors: 2
Total Number of Cores: 12
L2 Cache (per Core): 256 KB
L3 Cache (per Processor): 12 MB
Memory: 16 GB


System Version: OS X 10.8.2 (12C60)
Kernel Version: Darwin 12.2.0
Boot Volume: Mac HD
Boot Mode: Normal

[JFreak]

Have you tried to switch the digilink cable to another one? If that's broken it can cause clocking issues.

[RobMacfarlane]

Thanks JFreak, I'll buy another DigiLink cable and see if that helps it.

As a temporary measure, would clocking off an external source via BNC Wordclock cables work? I have a Neve 1073 DPD with a good clock on it, and wonder if this would fix the issue as well?

[JFreak]

I don't think so, as the 192 internal clock is pretty good but no matter what the interface needs solid connection to the card. If the problem indeed lies in the digilink cable you can clock it however you like and it will still fail. Let's hope your problem is solved by changing the cable

[boomsounddesign]

I sometimes get that issue with my Lynx Aurora 16. Going into the hardware dialog and switching to an external clock source then back to internal solves the issue.

[RobMacfarlane]

Ok, here's the update!

New Digilink cable is on order, until that arrives I'll have no feedback for that fix - however, reseating the cable a few times does seem to minimise the number of restarts required to fix the crackling.

Clocking via BNC does not seem to work at all! I'm using the Neve 1073DPD as an external clock, two BNC cables from Clock IN/OUT to the Ext. Clock IN/OUT of the 192. Going to the Setup>Hardware screen and selecting the external clock tells me that the Clock is out of range and PT will revert to the internal. Crackling resumes. Hilarious, as the internal clock keeps defaulting to 48k and the Neve is set to clock at 44k. Hmm.

As a possibly unrelated fact, when the 192 turns on (before the computer is on), it defaults to 48k. When opening a session, thats when the light switches to 44k, and crackling ensues. I can't remember off the top of my head (and don't have a working 192 to check), but don't 192 units default to 44k on boot usually?

[RobMacfarlane]

Yup, 192 was fully broke. Replacement being flown in. Let it be known that neither external clocking or new (shorter) Digilink cable fixed the issue in this case!

[JFreak]

Originally Posted by RobMacfarlane

Yup, 192 was fully broke. Replacement being flown in. Let it be known that neither external clocking or new (shorter) Digilink cable fixed the issue in this case!

Good to hear you got your problem sorted out :)