Hello Don, Your blacksmith is sure working up a sweat!  In my opinion,
your box is suffering from poor dampering causing excessive "damper
noise," probably accentuated by the fact that it's playing much too
fast.  My copy of "Harmonious Blacksmith" doesn't give a metronome tempo
but states that it is to be played "Andantino."  That is, "slow but not
too slow."  (My guess on this one is that there should be about one
second between major beats.)

After listening again to your MP3 file I have another thought as to
why the problem.  Since you are apparently hearing the noise only in
the recording it could simply be that you are recording at too high a
level and saturating the recording.  Saturation in digital recordings
sounds quite a bit different than it does in analogue recordings and
can be extremely harsh.  Try recording at a much lower level.  Now with
slowing the box, adjusting the dampers and reducing the recording
volume we just might have something.

Cheers!

Jim Heyworth
Sechelt, B.C., Canada