• Registered: 2011-06-05
  • Posts: 3

Topic: HDSPe MADI pops and clicks

Hello all,
We have a new playback rig on our show. Everything is running smooth, apart from a few hiccups that we could use your help with…
Here are the details:

2x Mac Pro, Main and Backup
2.66GHz Quad-Core Intel Xeon, 8GB RAM
700GB & 500 GB drives (system and audio)
OSX 10.6.7
Each is fitted with a HDSPe MADI card and the word clock I/O board (driver version 2.77).

MADI Bridge
3x ADI-8QS with the optional MADI card, ID’s 1, 2 and 3

Also in the system:
Rosendahl Nanoclocks word clock generator @ 48K
2x M-Audio 8x8 MIDI/USB interfaces (1 per computer)
16 tracks of Ableton Live (1-16) and 8 channels of NI Kontakt (17-24)

Here is how everything interfaces…
Optical on each computer (in & out) to ports 7 and 8 of the MADI Bridge. Each QS has a dedicated port on the Bridge, 1, 2, and 3 (in & out). This allows us to swap to the backup computer should the primary fail, and also A/B programming changes. All computers and QS’s are all locked to the Word Clock input via a dedicated output of the clock, and terminated on the device.  Also, this system is only for playback and live performance (no recording).


First question: Is this the best way to hook everything up? Are we over-engineering anything or omitting something obvious? We also plan on hooking up the BNC in & out of the HDSPe MADI card into an unused port on the MADI Bridge should we have a problem with the optical connection.

Here is the issue we are really scratching our heads about:
When using the backup Mac Pro, everything runs perfect.
However, on the main computer we get random pops and clicks which sounds like clock noise or jitter. But this only happens on outputs 17-24. When we open the meters window on the DSP Mixer, we can visually see them happening. What we also see (and the confusing part) is that several input meters also show pops and clicks at the same time we hear them on the output.
When we disconnect the optical in connection (either at the card or the Bridge), all popping and clicking stops on both input and output sides.

Any thoughts as to why this is happening? Is something “bleeding” over from the inputs to the outputs? If everything is locked to the same clock, why would we be getting clock jitter?
Is this a fault with the HDSPe card or an incorrect setting within the software (either in Live, Kontakt or RME DSP)?

We're going to continue troubleshooting, but just wondering if anybody could help with a point in the right direction.

Thanks for your help!
Josh Anderson
AHOD-Sound
CDS Kooza

2 Reply by MC

  • MC
  • MC
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  • From: Germany/Thailand
  • Registered: 2007-04-06
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Re: HDSPe MADI pops and clicks

Please look at the Settings dialog of the HDSP. When you see the clicks in TM then the dialog should read LOCK instead of SYNC for a short moment. Then you can be sure this is a clock problem.

Regards
Matthias Carstens
RME

MC's Website

  • Registered: 2011-06-05
  • Posts: 3

Re: HDSPe MADI pops and clicks

We have done a bit more work on this...

We seem to have narrowed it down to the optical ports on the HDSPe MADI card.

If we unplug the optical out of the Bridge, the popping is less frequent, but still present. Same thing goes when we unplug the optical in at the computer.

In the DSP settings window, we changed the MADI input from "Optical & Auto Select" to "Coax" and all the popping and clicking went away. Ran 2 weeks worth of shows without a problem.

The Input Status display always reads "No Lock" regardless of which input is selected.

Computer 1 and Computer 2 are almost identical (apart from a few pieces of software). Computer 2 has no clicking or popping regardless of how the input is configured.

Any ideas where to troubleshoot this next?

Josh

4 Reply by MC

  • MC
  • MC
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  • From: Germany/Thailand
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Re: HDSPe MADI pops and clicks

Which firmware is in that MADI card? Can you provide a screenshot of 'No Lock' despite using the input successfully?

Regards
Matthias Carstens
RME

MC's Website

  • Registered: 2011-06-05
  • Posts: 3

Re: HDSPe MADI pops and clicks

Hello,
Here are the screen shots you wanted.

1 shows firmware version
2 shows the settings that we currently use (no issues)
3-5 I was able to capture some clicks and pops in progress.

Inputs 21/22 that are showing signal I was playing via Kontakt. While the pops and clicks do happen when no signal is being passed, they are much more frequent when audio is being processed, especially outputs 17-24.

Thanks,
Josh

Pictures here!

6 Reply by MC

  • MC
  • MC
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  • Registered: 2007-04-06
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Re: HDSPe MADI pops and clicks

Thanks for the details and the screenshots. An invalid optical input signal can indeed cause these kinds of clicks/pops, and in some older cards this even happens with nothing connected at the optical in. Now usually this is no big deal, if that input is not used you will not select it as input. And: the input clicks/pops will only show at the output if you have an according routing set up.

In your case you should check the settings of the MADI bridge. With a valid MADI signal applied this error will not happen. It seems you either make a clock loop or try to mute the optical input.

We will check the latest MADI card firmware to see if we can improve this behaviour. The input signal detection seems to be not working good enough.

Regards
Matthias Carstens
RME

MC's Website