[dialup_sounds]

With a difference of 5 dB, one approximation for a Starship flyback boom at 20 km is a ∼50% increase in loudness over the Concorde boom (where 9 dB represents a loudness doubling;)

https://pubs.aip.org/asa/jel/article/4/11/113601/3320807/Sta...

tl;dr - it's very loud