Good detective work, Watson.
You did good to verify what you thought heard by another means before blaming/crediting your new addition.
We always listen more carefully when we change our system. We hear things that probably have always been there, but we never noticed them before 'cause we never listened that carefully.
Remember this if/when you jump into the cable upgrade morass. "New" things you hear with the new cables just might have been there all along. Most people are simply content to give credit to the new sounds without ever back testing.
Here's a little something you might enjoy.
http://www.hometheatersound.com/equi..._asc1_asb1.htm