[ELI5] How does something reach negative decibels?

Question

Microsoft made a -23 decibel room, but how does that work exactly? Once something hits 0 decibels how exactly can we measure it getting more quiet than that?

In: 24

Answer 1

0 decibels is the limit to what we (humans) can hear without artificial help. There are sounds that are below what we can hear, negative decibels.