[Warner306]

 Thanks, I will try out ReClock. What I forgot to mention is that I noticed when the audio delay is not applied, the taskbar icon of LAV audio is also not visible. It seems like the LAV Audio renderer is somehow not started or bypassed? Is LAV Audio still required if the audio is bitstreamed and not transcoded?      

 LAV Audio is part of the decoding, not rendering, process, so it is always used.     

 I tried using it with ReClock but it gave me no audio at all. Then I noticed that my renderer was previously not set to [Sanear] but to [Directsound Panarama...]. Changing it to Sanear did not fix the issue however.

Pressing 'O' during bitstreaming of Dolby Digital did show me that LAV Audio was not used as a filter, but Microsoft DTV-DVD Audio decoder. When playing a file with DTS it was using LAV Audio. If I switched audio tracks during playback (of the file with DTS) then it switched to the Microsoft DTV-DVD decoder again and audio was not in sync anymore.

Is there some configuration or merits that I somehow messed up?

EDIT:

When I disabled bitstreaming Dolby Digital then the LAV Audio decoder is used again. Enabling this will use the Microsoft decoder.

EDIT #2:

In my first post I mentioned that the B&W Panorama 2 did not support multichannel LPCM. I assumed this because the Windows Sound control panel only shows stereo (2.0) channels for the device, while with my previous receiver I was able to select anything up to 7.1. Using Custom Resolution Utility I was able to "hack" the driver and enable more channels for LPCM, but if you do the test sound on Windows, only the left and right channel would play sounds.

Now I downloaded both a Dolby TrueHD and DTS-HD speaker mapping file and played these with DSPlayer. The files will play sounds discretely through each channel. To my surprise I am able to clearly distinguish all the channels being played. In this setup those HD tracks are transcoded into LPCM by LAV audio and I have disabled mixing. The only strange this is the the subwoofer channel (LFE) is inaudible, while if I bitstream the DTS Core track the LFE channel is clearly audible.

SANITY CHECK
Am I correct to assume that using the Sanear audio renderer, with exclusive mode enabled and the mixer disabled, LAV Audio will just transcode all channels into LPCM and send 8 channel LPCM over HDMI to the Panorama? The fact that I am able to hear all channels means the Panorama actually supports multichannel LPCM, and there's no downmixing to 2.0 happening somewhere in Windows?

Another thing I found is that when you disable bitstreaming DTS-HD (but enable DTS) it will always prefer bitstreaming the DTS Core track instead of transcoding the DTS-HD track into LPCM. If I disable bitstreaming DTS it will choose the DTS-HD track and transcode that one. 

 For ReClock, you need to configure it outside of Kodi. It has its own control panel. But this doesn't sound like your problem.

The Microsoft DTV-DVD Audio decoder is news to me. I don't know if this is normal behavior or not. I assume you are using internal filters? Each filter should appear under codec info (O) with a little (i) beside it.

If letting LAV Audio do the decoding for you is working, I would stick with it. Otherwise, there may be no other solution. There should be no quality loss if you don't need Dolby Atmos or DTS:X.