As of the date of this answer, the X-59 has not yet flown, but according to the designers...
The ground noise is expected to be around 60 dB(A), about 1/1000 as
loud as current supersonic aircraft. This is achieved by using a long,
narrow airframe and canards to keep the shock waves from coalescing.
It should create a 75 Perceived Level decibel (PLdB) thump on ground,
as loud as closing a car door, compared with 105-110 PLdB for the
Concorde. The central engine has a top-mounted intake for low boom,
but inlet flow distortion due to vortices is a concern.
Additional information on this NASA project is available here.