how long for buffer?

[AlexS]

So now, I can confirm that yes, the buffer is in the Devialet, nice top quality Parisian memory, rather than the nasty cheap stuff in my PC.

Top quality Parisian memory? I thought the whole idea of French culture was based on flawed memory! (see M. Proust, "À la recherche du temps perdu")

Joking and your iTunes puzzle aside (unless iTunes is simply not Bit Perfect on Windows, and then there is no puzzle), thank you for trying Antoine's elegant idea out.
I really think you should report your 5000ms 24/192 issue to Devialet. Let them figure out if it can be possibly related to white noise. But that it's an issue in itself - there is no slightest doubt.
Congratulations on your 3rd star. Hard earned! Sometimes it pays being confused