There are a couple of comments I'd like to make on the recent
discussions on building a roll reader.

When I first joined this list a couple of years ago, it was after
I decided to look for a way to "save" my aging rolls in MIDI format.
Over time there has been discussions of this topic from time to time,
but never really enough information.  Usually, I'd be referred to some-
one who would it for a fee, or to someone who "had done it".  When I'd
contact the latter, the usual response was "Yes, I've done it, but I'm
not about to tell *you* how I did it".  Everyone had their little
secret which they wished to keep.

I've probably learned more in the last couple of weeks than the last
couple of years.  I want to say thanks to people for finally sharing
some information on this topic.  I really do appreciate it and can now
actually start designing a system.

I wanted to add that there is one factor being overlooked when
discussing the various ways of doing it and the 'accuracy' of each.
It seems to me that, unless one is looking to actually produce new rolls
based on the old one, one would want the highest degree of accuracy
possible.  Now, it seems to me that for someone like myself, a less
accurate system might be actually preferred.

It seems as though if all the signals to turn a note on and off were
precisely placed into the MIDI file (exactly the same as the roll) that
one would not have an accurate "performance" of the roll.  A player
piano does not hit the notes nearly as precisely, due the nature of
air being spongy.

It seems to me that if one wishes to reproduce a performance of a roll
to MIDI, that it would be more desirable to use the switches-on-the-
pneumatic strategy [than to record the motion of the keys in the player
piano].  If my piano happened to have a slow mechanism on one note,
I might hear that when it's playing the roll.  This would then be
reproduced into the MIDI file.  A more accurate "performance" would be
the end result.  Or, am I missing something and am way off base?

J W Miller
Saint Paul MN

 [ Jon, I think you are touching upon emulating the piano character-
 [ istics, which is really independent of capturing the data of the
 [ music roll.  An example is a Duo-Art performance: as the size of
 [ a chord grows (more notes struck at the same instant), the hammer
 [ velocity decreases.  It's just a characteristic of the Duo-Art.
 [ A good emulator which converts Duo-Art data for playing on a MIDI
 [ synth (or solenoid piano) takes this into consideration.  But,
 [ if you want to play Duo-Art data on a Duo-Art piano, no correction
 [ is needed (other than to account for the tracker bar details).
 [ The better the transcription accuracy, the better will be the
 [ performance.  -- Robbie