# Story from my music theory teacher



## violadude (May 2, 2011)

My teacher told me a story in my music theory class that I wanted to share with you guys and get your thoughts on.

My teacher had a musician friend who's specialty was computer generated music. He had an idea to make a computer system that you could program all the "rules" of 17th/18th century harmony and voice leading into and it would make chorales. So he programmed this system to do this and what it spit out were very rule perfect chorales that were very boring. They sounded like student counterpoint exercises rather than an actual piece.

What he then did was reprogram the computer system and instead of feeding it the rules of harmony and voice leading, he fed the system actual Bach chorales. The result was then the opposite. What it spit out was very inspired and beautiful chorales resembling Bach chorales, but they had a lot of very bad mistakes according to the rules.

What are your thoughts on this? What does it say about the rules of music? Or Bach? Or computers?

Keep in mind that the "rules" of counterpoint were derived mainly from Bach chorales. It kind of makes this story paradoxical in a way.


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## brianwalker (Dec 9, 2011)

Hofstadter thinks that this trivializes music; I don't care much for it. 

All great composers were always continually developing; these computers are, at best, performing the same function that any talented composition students can do; write pastiches. 

A computer that can arrive at its own style, not the mish mash of previous composers, but a new, organic style, is something at least eons away, if we ever get there.


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## HarpsichordConcerto (Jan 1, 2010)

The first part was no surprise. Follow the rules perfectly but no inspiration, perfect for studying. Even a non-musician like me might be able to do that if someone taught me the rules. Does this make me or the computer a real composer? I hope not and am not under any illusions that it does. Anyone can apply rules and come with sounds, all sorts of sounds. The second part was more interesting. Composers often bent the rules and they really composed.


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## jalex (Aug 21, 2011)

It says that at least some of the 'rules' of counterpoint are really only guidelines, and taste should take precedence over rules. This is common knowledge. 

It says that Bach was not a machine which applied rules, but a composer who applied taste. 

It suggests nothing really about computers, they just did what they were told.

The rules were derived only from Bach's preferences and most common habits, and thus do not really resemble his overall compositional practice. So it shouldn't be surprising that no music produced in the first scenario sounded like Bach.


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## LordBlackudder (Nov 13, 2010)

it has been done many times. the one i heard about also produced boring results.

it takes that human error to make something beautiful.

in this clip it shows a piece by a computer code and than by a human.






0:28


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## norman bates (Aug 18, 2010)

violadude are you talking about david cope?

http://artsites.ucsc.edu/faculty/cope/mp3page.htm


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## Polednice (Sep 13, 2009)

I don't think it's that surprising or difficult to understand. It's just a manifestation of the fact that the best music is music that bends contemporary rules - that's been true for the vast majority of music history. What you need to teach a computer is not a set of rules to follow, but a set of rules to work from, which it then varies to a certain degree. Such a computer could probably be made now, and its music would probably be quite good.


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## mmsbls (Mar 6, 2011)

I think these examples simply demonstrate that the computers programmed to composer music have not been taught well enough by their programmers. They apparently can create pretty music but not interesting music. Early chess playing computers had the same problem. The real advances in chess playing came from allowing computers to learn from the games they played. Basically the computers were programmed to modify their algorithms based on the output of games played. After enough learning, computers now can defeat even the best human grandmasters.

To become good composers computers must be programmed to vary their music creation algorithms and get feedback from listeners. Obviously they need to understand basic music theory (as do composers), but they also need to understand something about surprise, novelty, innovation. I suspect that creating good computer composers would not take too long (a couple of decades perhaps) if there were enough groups working hard on the problem (coupled with significant composer input).


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## Argus (Oct 16, 2009)

Allow the computer to be a computer rather than trying to make it human and the results will be better. Here's a great example, but you have to listen all the way through or you won't get it:






However, there will always be the human element in the laying down of the rules for the computer to follow. In this way the computer is more or less acting like players in a John Zorn game piece or in Paragraph 7 of Cardew's The Great Learning.


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## Huilunsoittaja (Apr 6, 2010)

There must be rules in music, but there must also be the Human element of creativity including the discerning of what's an appropriate time to break a rule for an affect. That's what constitutes some of the greatest music ever written.


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## Philip (Mar 22, 2011)

violadude said:


> Keep in mind that the "rules" of counterpoint were derived mainly from Bach chorales. It kind of makes this story paradoxical in a way.


You have to take into consideration that computer composition is an application of artificial intelligence (computer science). The result of any experiment is thus related to what heuristic approach the computer scientist chooses.

Early concepts in computer composition were relatively simple. Similarly to your first example (rule-based), some algorithms relied heavily on Markovian processes, ie. relying on statistical distribution of what comes next, given the present. For example, solutions for future notes in a composition are selected according to an arbitrary distribution, and rejected if they violate any rules of composition. One of the first attempts:

Lejaren Hiller - Illiac Suite for String Quartet, mvt 1 (1956)





Later in AI came the expert systems. Essentially, they are knowledge-based decision-making programs. In an expert system, rather than your usual hard-coded algorithm, only the knowledge of the system is predetermined. Similarly, or perhaps exactly like your second example, the Bach chorales are used to derive the knowledge-base.

An Expert System for Chorale Harmonization, by K Ebcioglu (1986)
http://www.aaai.org/Papers/AAAI/1986/AAAI86-130.pdf

The quality of the results is mostly related to the quality of the heuristics, and doesn't really offer any insight on the intrinsic nature of music with respect to its 'rules'. Therefore the paradox in unapparent from the computer scientist's point of view.

Consequently, or intuitively, using the most sophisticated algorithms would only yield inferior-to-equal quality compositions when compared to the actual pieces from which these algorithms are inspired (speculative on my part, because...) then again, mathematically, a monkey on a typewriter could very well write Hamlet, if given enough time.


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