I have noticed a particular noise on some recordings I made of an
Empress Concert Grand.  The noise sounds like some loose metallic part
vibrating.  I am wondering if anybody can identify the noise.  I myself
cannot tell if it is damper noise, a loose metal part or screw or
caused by the zither paper slightly in contact with some teeth.

Do recordings of music boxes often have such "features"?  How do others
deal with them?

To my mind, the recording should sound like a music box is in the room
when played on a good stereo sound system.  It's possible I put the
microphones too close and picked up the mechanical noise.  You would
not normally put your head that close to a music box.  But in testing,
that setup appeared to be optimal.  Further away and I began to pickup
sounds outside the house.

I have notes somewhere of microphone placement tests and can look for
them.  As I recall, the microphones were placed about 12" back from the
front edge of the music box and off to each side about 4", raised about
8" above the top edge of the cabinet and aimed slightly off-center of
the disc to the left and right.

I do not notice the noise when listening to the playback with typical
portable CD player type headphones.  Nor did I notice it when making
the recordings and playing them back on the home sound system.

Beyond that, I am wondering if there is any sort of filter that can be
used in a wave editor to reduce the effect of this particular noise.
I have examined files created in direct conversion to WAV and they do
not appear to be clipped.

Attached is a recording of the "Harmonious Blacksmith" played on the
Empress.  The recording was made using two microphones on a video tape
using 14 bit PCM sampled at 44,056 samples per second.  This recording
was converted directly to MP3 from the line input to the sound card on
my computer using Music Match Jukebox.  (44,056 is what you get when
you use our NTSC American TV standard tape recorders, on European PAL
systems you get 44,100 samples per second which just happens to be the
sample rate used to make audio CD's -- in case you ever wondered where
that standard came from.)

It would be useful to many of us if some of our knowledgeable readers
could put together sets of sample erroneous sounds caused by various
problems on music boxes, organ pipes, pianos, etc.

Don Shenbarger

 [ Don, your recording is a nice as any I've heard; most have lots
 [ of thumping and scraping sounds.  Too many record producers seem
 [ to lose sight of the goal: music.  I feel sure that the composers
 [ and noteurs disliked the extraneous noises.  I'll place your MP3
 [ file, and two other versions of less size, at
 [ http://mmd.foxtail.com/Sounds/   -- Robbie