In the latest RC tabs that are suspended turns the favicon grey. thats great and all, but doesnt really work well with favicons that are allready in greytones
No tabs suspended:

both tabs suspended:

I suggest to put a sleep icon where volume icon is on tabs with sound. that way you would also have a quick way to unsuspend a tab with out entering it. just by clicking on the icon.
would look like this:

I would probably still keep the greyd out thing.
the icon is

could also use:

if people prefer, i dont, but doesnt matter to me