General question about exhaust volume

For the time being, I didn’t know where the theme would fit best, so I’m sorry if it’s not in the right place. Now to my question: The Hyundai i30 N should probably be the loudest car from work, but now I ask myself if I want to compare the sound with an e.g. Rs5 and look at the DB volume on the sheet then there is no real difference in the driving noise?! So actually an Rs5 to an i30 N is equal loud or ?? Except of the standing noise. So again briefly and concisely: Can you say that an i30 N vs is a Rs5 louder while driving or not? Since on the sheet are the same DB data. Another nice evening Lg