It's easy to adjust this on an upright piano. Remove the front of the case below the keyboard and you will see an adjustment screw, probably a wing-nut close to the pedal. On a grand piano the pedal mechanism can be a bit more complicated, but simple for a technician to adjust.
If you get different amounts of damping between the bass, mid range, and treble, that could indicate a more serious problem, for instance one of the bearings connecting the lever that lifts all the dampers to the piano frame has cracked and broken. Fixing that properly might involve some metalwork, and in the worst case you have to remove some strings to get access to the problem. That is most definitely a job for a technician, because doing it wrong can crack the iron piano frame, which is terminally fatal.