Hello,

I am pretty new to the RME scene and have been trying to troubleshoot and eliminate the "snap crackle pop" effect I seem to always get playing back anything in Reaper with my RayDAT card whenever I have the sample rate set to 192K.  I also get "dropouts" sometimes where you hear nothing coming out in the headphones for fractions of a second.

It does not matter what buffer size I use now, I get the same amount of snap crackle pop with buffer size anywhere from 128 to 4096.  It is not constant, it is sporadic but happens at least every couple seconds or so while listening to audio if I am at 192KHz sample rate.  Like listening to an LP that has some clicks and pops on it.

If I drop the sample rate to 96KHz I can run the lowest buffer size and never hear the first click/pop/etc.

Clock is set to Internal.  I do have a Focusrite Clarett OctoPre connected, but I have ruled it out because it happens whether I have it powered off or on.  Again, I am listening to "local" content in my DAW (virtual synth instruments), sending output directly out the SPDIF out.  So I probably don't need to waste time troubleshooting  my optical cables, although they are brand new Hosa premium's.

Headphones are Senal SMH-1000's connected to a Grace Design M900 from the RayDAT's SPDIF out on the digital breakout cable.  The SPDIF cable is a brand new Hosa digital coax SPDIF cable.  I suppose it is possible the problem could be the Grace M900's DAC that the SPDIF output comes through before I get to hear it through the headphones, but not sure.

The system is Windows 7 x64 SP1 + a small handful of misc. other critical fixes, Asus X99-E WS (original model) with i7-5960X, multiplier overclocked to 4.7GHz (47X with 100Mhz BCLK) and 4.5GHz cache clock and watercooled.   C states are completely disabled and the system has been very stable.  I switch the system into High Performance Windows power profile whenever doing any music/DAW stuff.

DPC latency checker is around 50-75 microseconds typical with occasional spikes above 100 but still stays well in the green whenever I am in Reaper or doing other music stuff.  Only when there is significant disk IO or  doing other non-music-related stuff do I see the latency go anywhere north of 130-150 or so.  I have NEVER seen any dropout, click/pop/etc ever reflected in the DPC latency checker output by a higher latency level, it tends to stay very steady around 50-75 microseconds.

I had used the post in the tips/tricks area to reconfigure my 2 GTX1080 video cards to use MSI interrupts, but after a little shuffling around I got the RayDAT into PCIE slot 4 where it does not have to share an IRQ with anything.  Even at that, it makes no difference for this 192KHz snap crackle pop issue.

Does anyone have any ideas?  I am suspicious of the notion that this type of thing is "normal" or "to be expected".  The fact that increasing the buffer up from 128 (which the system does seem to work fine with, except for the clicks/pops) to larger buffer sizes - even 4096 - does not really change the frequency of these clicks/pops makes me think it is not a buffer size issue at all.  Seriously - as soon as I set a lower sample rate in the RayDAT's control panel applet (I have tried 96KHz, 48KHz, and 44.1KHz) I have no trouble even at the lowest buffer size for each of those respective sample rates.

I'm not sure I would really record much or any at 192KHz anyway (I know, the files recorded will be enormous etc. etc. etc.), but with the specs of this system I believe it should be able to handle it.

Does this sound like anything familiar to anyone?

Thanks,
RetroRambler

PS:  Driver version 4.2.1, Firmware 14