Where do I go to disable Secondary Audio?
I believe it's somewhere inside the Setup Menus of the 4010. I haven't powered on my 4010 in ages so I can't be more specific.
OK found it - on page 32 of the Manual:
When disc is playing, press "MODE" button then use the direction keys to navigate.
BD Audio Mode can be toggled between HD Audio Output or Mix Audio Output.
Default is Mix. Switching to HD Audio Output will send the output as bitstream if you enabled HDMI Audio out to bitstream earlier.
So you recommend setting to PCM because it will sound much better using DLink?
No. The converse is what I am recommending. I'd use HD bitstream because I think it sounds better. But with some of my BDs, which are encoded in MPCM and you have no choice, DenonLink helps improve them.
Another question I have is listening to SACD using DLink. How do I get the front panel display with the 4810 receiver showing DSD MULTI DRCT? Here is a picture of an owner showing the DSD MULTI DRCT with the 4810 receiver:
SACD DSD can only be sent from the 4010 in DSD mode over Denon Link.
Have you tried using the Direct/Stereo button on the Remote?
That should disable any bass management and the display should read DSD Multi Direct, I suspect
Is the small DSD light enabled in the 4810 panel even if it doesn't say DSD Direct in the Big Font?
Read page 87 and 88 of the 4810 manual. Even if you feed DSD in, it would say Multi Channel In. It only says DSD Multi Direct when you enable Direct mode (no bass management or Room EQ)
Bear in mind that any DSD that is fed into the 4810 gets converted to PCM IF you enable Room EQ or Bass Management.