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From: UUCJEFF@ECNCDC.BITNET
Newsgroups: comp.ai.digest
Subject: RE: I got rhythm
Message-ID: <19880918192105.6.NICK@HOWARD-JOHNSONS.LCS.MIT.EDU>
Date: 18 Sep 88 19:21:00 GMT
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Date: Thu, 15 Sep 88 14:44 EDT
From: UUCJEFF%ECNCDC.BITNET@MITVMA.MIT.EDU
Subject:  RE: I got rhythm
To: ailist@AI.AI.MIT.EDU

>
>It comes down to this:  Different actions require different processing
>overhead.  So why, no matter what we do, do we perceive time as a constant?
>Why do we, in fact, have rhythm?  Do we have an internal clock, or a
>"main loop" which takes a constant time to run?  Or do we have an inadequate
>view of consciousness when we see it as a program?

>Phil Goetz
>PGOETZ@LOYVAX.bitnet

Being both an international jazz recording artist and computer programer,
with a growing background in AI (but not the AI religion),
I will join this jam session on this tune called "I GOT RYTHM".

I really dont know how much I can answer Phil's questions,
but I can give some perspective on how a musician or drummer or someone
with good time views rhythm.

Start out by looking at some of the terminology surrounding rythm, we say
something is "in a groove" or  "in the pocket" or "it swings".
The first two imply precision, ease, and continuaty, while "swing" implies
motion.  All three terms imply "autonomy", and that is so true.
When something "swings", the music goes by itself.
"Time" is another important word.  For musical genres which are known to
have advanced forms of rythm, "TIME" is a very mutable characteristic.
By laying slightly back of the beat, you make the sound float in the air,
and by pushing ahaed slightly, you can give music drive and fire.
To be able to master it and use it, I would tend to say it involves all
parts of the human psycho physical structure... You certainly excite  your
nervous system, you need your reflexes to control the muscles that are tapping
the foot or playing the instrument, the emotions are involved, and on the
mental level, you need to concentrate and use your ability to image things.
Then of course there is the musical idea itself behind the whole thing.
Certainly if you are lazily tapping your foot and not paying too much
other attention, these other charactaristcs will take a lessor role.
But to the extent you are tapping good time, you must have the automatism
there.  Where this comes from, I don't know, but that is how you feel it.

Therefore, I would suggest that we do not perceive time as a constant.
We don't in ordinary life, and we don't in music.  If we are really
getting into a piece, we could listen for hours and it will not seem
like a long time.  I heard a live performance of Stavinsky's La Sacre du
Printemp, even though it is 40 minutes, it went by like 10 minutes.
Isn't it a famous quote of Einstein when asked to explain relativity,
and he said "If you are sitting next to a beautiful girl, hours go by
like minutes, but if you are sitting next to ..., minutes seem like hours"

Phil asked about programming this.  Since I have become disillusioned at
how generic most jazz today sounds ( Yes Wynton, that's you) my musical
direction has been to make a One Man Digital Band with an Atari ST MIDId
to my MIDIcapable trumpet and a variety of synthesizers and drum machines.

I have been programming a walking bass line. It reads my trumpet and
figures a bass line in real time.  If I change keys, It changes keys.
If I hold a note. It holds a note.  etc...
The only way to program rhythm and make it sound "human", is to study humans,
identify the slight delays or anticipations, and try to come up with a
scheme so it is related to the appropriate information of the other music.
This itself is a creative act on the part of the human being.
There are no fixed schemes on determining what is approprate, one has to
do the research and evaluate the results.  Whehher you can get it down to
an adaptive filter is anyone's guess.

At present there are some people working in this area, and there are even
some commercial products out that based on some of the concepts I have
presented.  There are devices which are designed to take a perfectly timed
computer generated drum sync track and massage the pulses so it will give
a human feel.  On the unit are switchs to make it sound like a
60s Motown feel, a 70s L.A. sound, brazillian, and on and on and on.
I think I have said enough, I hope that answer's Phils question.  If not
I hope that this was interesting otherwise.  If not, solid..........

Jeff Beer, UUCJEFF@ECNCDC.BITNET... Chicago Ill....
"I'll play it and tell you what it is later"... Miles Davis