Clocking issues?

[digidesigner]

Yesterday I had this strange problem with D-Show system. System runs AES/EBU out from FOH rack to Meyer Sound Galileo in A that is set to receive digital input. It has been working fine for months, but yesterday the system started crackling out on me. I had a Pro Tools HD system with some tracks + live inputs on my show. I tried to restart all the components, console, Pro Tools and Galileo with no positive results. This was all at the rehearsals. Finally I dropped the digital and did the show with analog connection between the console and Meyer controller. After the show I tried to reconnect and troubleshoot further, but guess what, yes, the system was running fine.

I'm thinking most likely the Galileo was gone bananas, but I can't be sure unless the problem returns and I can do a proper troubleshooting. Has anyone else had problems like that? The only thing I did during the day that was not normal was that I did a Venue system restart at some point and I forgot to turn off Pro Tools system before I did it. But as I said, later on I did a proper shut-down and restart and still there was sync clicks and distortion out of PA. I remember hearing a click from PA even when D-Show master was muted. The sound out of analogue outs was fine all day as I was feeding a TV truck from analog outs and they were happy.

[Chris Lambrechts]

Hey Kristo,

Did you get to try feeding the digital outputs into something else then the Galileo ? I think you mentioned on the phone possibly trying the spdif outputs into your laptop ?

Ideally you would take those aes outputs and feed them into something else then the Galileo if you want to rule that out.

Chris

[digidesigner]

Originally Posted by Chris Lambrechts

Hey Kristo,

Did you get to try feeding the digital outputs into something else then the Galileo ? I think you mentioned on the phone possibly trying the spdif outputs into your laptop ?

Ideally you would take those aes outputs and feed them into something else then the Galileo if you want to rule that out.

Chris

Hi Chris, yes I was about to try that, but I was kicked hard for every minute that we had to delay the rehearsals (it was a music awards show and everything running late as usual) so instead I went analog and hoped to do the troubleshooting after the show.
But then as I said in my first post the system was acting just fine after the show

The Meyer Sound guys are actually here today and we discussed different versions of what might have been going on but no-one can be sure unless it happens again, witch I'm hoping it won't

About going digital in to the Galileo, I learned an interesting thing that might be called a bug in the Galileo, you need to delay left input by 2 samples (when running 48khz signal into it) to properly align L and R. This might be useful to someone not knowing about this.

[Sheldon Radford]

Hi,

Each AES inputs on the Galileo (and most AES-equipped devices these days) has a built in sample rate converter (SRC), which mitigates the need for a dedicate word clock connection between devices. It's sometimes possible to disable SRC, in which case a separate clock connection would be needed in order to establish a common clock between the console and processor and avoid pops/clicks.

However, in reading through the Galileo user guide it doesn't look like it's possible to disable SRC, and the unit doesn't support external word clock connections so it's difficult to say what could have caused the pops/clicks. About the only thing left to check would be the cable between the console and the Galileo, to ensure it's a 110 Ohm cable rated for AES/digital use.

Keep us posted if the source of the issue is ever determined.

Sheldon

[digidesigner]

Originally Posted by Sheldon Radford

Hi,

Each AES inputs on the Galileo (and most AES-equipped devices these days) has a built in sample rate converter (SRC), which mitigates the need for a dedicate word clock connection between devices. It's sometimes possible to disable SRC, in which case a separate clock connection would be needed in order to establish a common clock between the console and processor and avoid pops/clicks.

However, in reading through the Galileo user guide it doesn't look like it's possible to disable SRC, and the unit doesn't support external word clock connections so it's difficult to say what could have caused the pops/clicks. About the only thing left to check would be the cable between the console and the Galileo, to ensure it's a 110 Ohm cable rated for AES/digital use.

Keep us posted if the source of the issue is ever determined.

Sheldon

Hi Sheldon,

Yes we had correct cabling between the two and I did try using the spare cable with no luck. Now the system has been working fine the next couple of days.

I wonder how these bizarre errors happen mostly when you have an extremely important show but never when you just mess around for fun