Aes still popping on output for sc48

[soundbobby]

I switched our dbx driverack 4820 to accept 48khz input but there is still an occasional popping . I'm using a basic xlr but my run is 10 feet. Should I be using a aes cable? Is this the problem?

[aarono]

Hey Soundbobby,

Sending to both of your posts so you get the reply :)

This certainly sounds like the pops you'll hear if the clocks of the two systems are drifting apart. If you haven't already you should connect the wordclock Out of the SC48 to the Wordclock In of the dbx 4820. Let us know if this resolves your issue or not.

All the best!
Aaron

[ionStorm]

If connecting the Wordclock doesn't help, you may want to consider using proper AES/EBU cables. Impedance mismatch is trouble...

[soundbobby]

I'm using aes in and out right now. If I connect the wordclock bnc, do I still need to use aes cable? Thanks for the advice

[Rockpolice]

Originally Posted by soundbobby

I'm using aes in and out right now. If I connect the wordclock bnc, do I still need to use aes cable? Thanks for the advice

Yes you need. The word clock just syncs the different machines' clocks to exact same time.

[Sheldon Radford]

Hi,

This definitely sounds like a clocking issue, especially if the popping is periodic an d happens regularly every few seconds. Even though two devices are set to 48 kHz it doesn't guarantee a connection will be glitch free, because the clocks may still be out of synch with each other.

Think of it this way: if I start running at 5 miles per hour, and then a few seconds later you start running at 5 miles per hour, we're both running at the same speed but we're out of synch with each other. This is what happens when two digital audio devices have the same sample rate, but don't have a common clock to allow them to synch up.

There are several ways to establish a common clock:
- via the AES signal itself. Make sure the device receiving audio is set to slave to the AES input. Nearly all devices can sync to the AES input, and this is by far the easiest (no add'l cables req'd)
- connect a physical word clock connection (BNC cable) between the two devices. Make sure the device receiving audio is set to slave to the word clock connection

If the receiving device is set to "Internal", then it is not using the same clock as the console, and popping will occur.

Sheldon