The ones in the box are dedicated to the AVR, not for stand-alone testing. You could get your own SPL meter to check levels if you wish. I would start by seeing how the AVR does before starting down the "I wanna' do my own measurements" rabbit hole.
If you really want to do your own measurements, you'll need a calibrated mic or SPL meter (range from ~$100 up; I paid ~$600 for my earthworks measurement mic, but that is not a hobbyist item, I used it for work) and SW (again, free like REW up to $100k analysis programs).
To start with just get the AVR and set it up. You might find yourself liking the music and movies enough to spare yourself the incessant need to measure and upgrade.
"After silence, that which best expresses the inexpressible, is music" - Aldous Huxley