1 Topic by thom (edited by thom 2020-11-02 04:42:09)

  • thom
  • New member
  • Offline
  • Registered: 2020-10-31
  • Posts: 2

Topic: ExpressCard > Thunderbolt 3 distortion

First time posting here, but a long time user of a Multiface II via Expresscard.

I'm trying to get them running on a new Win10 laptop via Thunderbolt 3 > Startech Thunderbolt 3 to 2 adapter > Sonnet ExpressCard Thunderbolt Adapter.

Initial BSODs from a Driver Verifier DMA Violation seem to have been solved with the registry tweak recommended in the tips and tricks forum. Thanks!

Now the interface is producing sound, but there is a distortion or bitcrusher type effect on audio played back by apps such as Windows Media Player, VLC, web browser or the windows os sounds themselves.

I checked the RME driver IRQ and it does look like it's being shared, which I can't change so far.

However, if another app such as Blackmagic Design Resolve or Adobe Audition is launched, then the distortion on sound played back by Windows Media Player, VLC, browser etc disappears and all audio becomes clear.

Just running either of these apps in the background seems to fix the distortion. If I shut them down then the the problem returns.

Any ideas what might be going on?

2 Reply by thom (edited by thom 2020-11-02 04:56:53)

  • thom
  • New member
  • Offline
  • Registered: 2020-10-31
  • Posts: 2

Re: ExpressCard > Thunderbolt 3 distortion

Still trying to track down what is causing this puzzling distortion problem, and what might fix it.

These are the observations...

Audio becomes clear under processing load
The distortion or bitcrusher type sound is not consistently present.  For example, audio playback by Windows Media Player will become clear while Photoshop is rescaling an image. In other words, while the pc is under a higher processing load the audio distortion clears up.

Audio becomes clear while certain apps are running in the background
After starting Blackmagic Design Resolve (a video editing app) the distortion stops and audio playback remains consistently clear  from all sources until Resolve is closed. Resolve doesn't need to be working hard or even have a project open, it just needs to be running in the background. The improvement happens within a fraction of a second after clicking on the Resolve launch icon. It seems that launching Resolve switches something about the windows audio system right at beginning of Resolve's launch sequence which fixes the distortion problem of audio playing back through Windows Media Player, VLC, system sounds etc.
Running Adobe Audition also seems to stop the distortion in the same way.

The usual optimisations make no difference
Power plan is set to no suspend, cpu etc. set for staying on 100%
Processor scheduling is set for best performance of background services.
Changes to these make no observable difference.

Resplendence LatencyMon is reporting no problematic drop outs.

And a question...

IRQ sharing - does MSI mode work for RME drivers?
Using MSI_util_v3 shows that RME Hammerfall DSP is sharing IRQ 16 with Intel(R) Serial IO I2C Host Controller - 06E8.
RME Hammerfall DSP is running in LineBased mode. There is an option to change it to MSI mode which I've read could give better results in IRQ sharing situations. However, if MSI mode is enabled no playback is possible through the RME device. Windows says the RME driver is working ok, and is available as a playback device in windows, but Windows Media Player won't play and no other app will either.

I've seen indications in this forum that RME drivers should work in MSI mode, but no confirmation of a working example.

Does MSI mode work for driver hdsp win 4.3.5.0 ?

Thanks.

Thom