Thunk, wunk

[Newton Hunt]

> Any ideas? I wondered about a downbearing problem or something 
> but would assume such a design flaw would be unlikely.

Who gave you permission to assume that?

Check the bearing and then un-bridge a string and pull it up and see if
there is a gap between the string and the bridge.

Pluck the strings and see if there is a difference in the tone.  Put a
tuning fork on the bridge and see if it has sustain, more or less than
in other areas of the piano.

The strings can be relatively new, damage, poorly made and certainly 
badly scaled.  

Steck made some very nice little pianos but there is a reason for it not
sounding the way it should.  Discover that and you are well on a way to
a solution.

		Newton