Cobranet thuds?

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I am wondering if anyone has any experience of cobranet?

I have a simple(ish) setup:
ASI5408 (PC)-> Switch -> Symnet cobralink -> Symnet -> Symnet 8x8 DSP

Audio transport seems to be working fine but I have been a little scared to test further as when no audio is been sent I get massive violent impulses approximately every minute on the outputs of the 8x8 DSP. I don't have any problems using the analog inputs on this DSP.

One weird thing I have noticed is that the Cobralink is not configurable through Cobranet discovery. I see its IP address and MAC address but no other information can be gathered. I am guessing it does not use the cirrus logic chipset?

Both devices are set to 24bit/48kHz/5.33mS latency I am using the first unicast bundle 256.

any thoughts?
 
I had a look at this again. This time I created a simple system that looped back the Cobranet from bundle 256 via the 8x8 dsp into bundle 257 and recorded it on the same computer that sent the audio. I also changed the computer with the ASI5408 in it. During 5 mins of recording I noticed no glitches. So hopefully it was just a one off bug related to either the computer or the Symnet composer site file. With +24dBu output capability from the 8x8 DSP it doesn't matter if the amp gains are down a full scale output signal is insanely loud.

One thing I did notice is that the Cobranet goes right up to 0 dB fs on the level meters, the 8x8 DSP uses floating point processing but even so I think the first thing in the final system will be -20dB of gain so that levels match the analogue inputs on the 8x8.
 
So routed the Cobranet to the speaker outs and found its not fixed, however this time I was wearing hearing protection so it was less terrifying. I get the thuds more often when there is no audio been transmitted. I now have some new ideas though:

1) the 8x8 DSP has analogue output attenuators so I will engage them and it will hopefully make testing more pleasant.

2) I can now route audio back from the DSP via Cobranet so it will be interesting to see if I can successfully record the analogue input without glitches.

3) I'm using a gigabit switch, it might be worth trying a crossover cable instead, however if this where the problem I would expect that I would have heard errors in the previous Cobranet loopback test.

4) There is a mention in the manuals of a different update procedure for the Cobranet firmware to the Symetrix firmware so I could try that.
 
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