My Piano Has a "muffled" Sound

I wouldn't want to be cliché... but have you checked the damper... to make sure it isn't also partially dampening the hammers?.

In addition:

The hammers may have absorbed moisture

the grooves in them can be very evident, especially on the highs

it can depend on the regulation. In fact, a not "full" hammer stroke can compromise the power of the attack on the string.

Even the regulation of the dampers can have an effect

Send me some photos and audio files, if you want.

Ciao Paolo

Unfortunately I fear that this is the problem

pianoexpert wrote:

The hammers may have absorbed moisture

The room is humid (basement), the pf is between 2 windows and is also against a wall exposed to the north

Any tricks to contain the "phenomenon" .... ?

a room dehumidifier. Also try not to lean the instrument against a damp wall. In any case, the best thing is to move it. The center pins of the action can also be blocked. Symptom: mechanical parts that return to their initial position with difficulty.

Hi, I am seeing this post now. I recommend a Piano life saver, a device created specifically for those who have a piano in an environment with strong humidity fluctuations. You can find it on the website www.pianolifesaver.com It is very effective.