Thank you !
So, it was a bug (and I have to admit that I was tempted to do that check, but it was too late and I feared I could disturb someone with my tests).
So, I'm not deaf !
I'm now convinced that ASIO4All doesn't introduce unwanted "mathematical" artifacts, and that when I hear more "3D" it's not because of a psychological artifact (the "louder" sound could be, on the contrary, a psychological consequence of the "3D").
So, please listen !
Mathematics and Physics are important in HiFi (I guess so because I'm a Theoretical Physicist), but this discussion reminds me "cables".
As the Physics is concerned cables (apart the trivial ones) should "sound" all identical, differences in parameters being so small that they should be non audible.
On the contrary differences are audible. Not so much to convince me to buy cables costing > 1000$. My cables are low priced , but when I switch I hear the difference