Path: utzoo!attcan!uunet!cs.utexas.edu!csd4.csd.uwm.edu!marque!lakesys!mikes
From: mikes@lakesys.UUCP (Mike Shawaluk)
Newsgroups: comp.music
Subject: Re: MIDI pitch inversion
Keywords: MIDI, composition, sequence
Message-ID: <1034@lakesys.UUCP>
Date: 2 Sep 89 12:07:55 GMT
References: <124101@sun.Eng.Sun.COM>
Reply-To: mikes@lakesys.UUCP (Mike Shawaluk)
Organization: Lake Systems - Milwaukee, Wisconsin
Lines: 24

The referenced article on MIDI pitch inversion was quite interesting, but I
thought I'd throw in a short note concerning what I perceive to be the
difference between MIDI inversion and "playing a score upside down", which
the article's author referred to in his opening anecdote.  I guess the
obvious difference is that MIDI notes are numbered diatonically (i.e., via
half-tones), while musical scores are "numbered" by a combination of whole
and semi-tones (i.e., the C-Major or A-Minor scale).  Also, the type of
symmetry you would get depends on whether you invert each staff separately,
or whether you also interchange the treble and bass staves.  For example, if
you just invert the treble staff, the note of symmetry becomes B (the middle
line), whereas if you invert the pair together, the note of symmetry becomes
middle C.  Also, it becomes interesting when a song is in a key with sharps
or flats, because they will now fall on different notes than they were
intended (except, of course, for a single staff in the key of F major/D
minor).  I won't go into any more than that right now (because I'm too lazy,
I'll leave that for someone with more energy :-), except to mention that I
remember seeing a song in one of my daughter's piano lessons by one of the
traditional composers (Beethoven or Mozart maybe), which was a short piano
piece which sounded the same when played rightside up or upside down!  A sort
of symmetrical musical palindrome!)
-- 
   - Mike Shawaluk 
       (mikes@lakesys.lakesys.com  OR  ...!uunet!marque!lakesys!mikes)
   "If spirit == essense, then spiritual == essential!"  - me