links // 2007.05.08 08:54:25 [hh]

"Wolfram Tones": "automatisches Komponieren" im Web

Ein Service namens "Wolfram Tones" von Wolfram Research – Hersteller der Mathematik-High-End-Software "Mathematica" – bietet unter dem Titel "An Experiment in a New Kind of Music" ein interessantes Web-Tool zur Generierung von Ringtones und MIDI-Files.

Von der englischsprachigen Web-Site über Stephen Wolframs Ideen und das Online-Tool:

"When prominent scientist Stephen Wolfram published A New Kind of Science in 2002, it was immediately hailed as a major intellectual landmark. Today the paradigm shift that Wolfram's work initiated is starting revolutions in a remarkable range of areas of science, technology--and the arts. WolframTones is an experiment in applying Wolfram's discoveries to the creation of music.

At the core of A New Kind of Science is the idea of exploring a new abstract universe: a "computational universe" of simple programs. In A New Kind of Science, Wolfram shows how remarkably simple programs in his "computational universe" capture the essence of the complexity--and beauty--of many systems in nature.

WolframTones works by taking simple programs from Wolfram's computational universe, and using music theory and Mathematica algorithms to render them as music. Each program in effect defines a virtual world, with its own special story--and WolframTones captures it as a musical composition.

It's all original music--fresh from "mining" Wolfram's computational universe. Sometimes it's reminiscent of familiar musical styles; sometimes it's like nothing ever heard before. But from just the tiniest corner of the computational universe WolframTones can make everyone on Earth their own unique cellphone ringtone. It's a taste of what it's like to explore the computational universe--and a hint what's to come..."

Die häufigsten Fragen und Antworten von Wolfram Research

What is the mechanism behind WolframTones?
Each composition is produced by running a program found by searching the computational universe, taking the pattern the program produces, and converting it to a musical score. WolframTones uses a type of program known as a one-dimensional cellular automaton, or Wolfram automaton, studied by Stephen Wolfram since the early 1980s.

Why does WolframTones work?
It's a rather direct consequence of a core phenomenon of Stephen Wolfram's science: that programs with very simple underlying rules can generate great complexity of behavior. (See Chapter 2 of A New Kind of Science.) The presence of simple rules leads to local regularities, and a certain overall consistency in each composition. The complexity leads to "surprises" that our ears seem to like. One day we'll probably understand more about how it relates to human auditory perception. (Compare the discussion in A New Kind of Science, for example about chords.) It's presumably connected to why visual images from A New Kind of Science have become so popular.

Does WolframTones use stored samples of existing music?
No. Everything it generates is original. All its compositions are built up from scratch by running programs that it finds in the computational universe.

Does WolframTones use randomness?
Once WolframTones has picked a Rule to use, all the notes it will generate are in principle determined. But that doesn't mean there's an easy way to predict them; in fact, Wolfram's phenomenon of computational irreducibility shows that in general there can't be. So even though there's no explicit randomness put in, WolframTones rules can still intrinsically generate effective randomness. But there are still rules, and that's crucial to producing compositions that globally "make sense."

Does WolframTones use musical principles?
Only in very local ways. It uses musical scales, and certain local rhythm structures, to convert the results of its simple programs into musical scores. But no overall rules such as counterpoint are directly included. Sometimes, though, they can emerge. But often in rather "creative" ways.

Does WolframTones use mathematical principles?
In a sense it uses a generalization. Traditional mathematical systems (like arithmetic and geometry) are specific examples in the general universe of formal computational systems. WolframTones uses a broader set, so that in a sense almost every composition is associated with a different possible generalized kind of mathematics. Like traditional mathematics, though, WolframTones is based on using definite abstract systems that have their own "internal logic." If history had been different, perhaps Pythagoras would have used WolframTones rules instead of mathematics and numbers to describe music.

Why do I see definite classes of patterns across WolframTones images?
Those are essentially the Wolfram Classes, discovered by Stephen Wolfram around 1983. There are four Classes: 1: becomes uniform; 2: becomes cyclic; 3: makes randomness; 4: makes complex localized structures. WolframTones mostly picks Class 3 and 4 rules to use. Class 4 rules often yield the richest compositions.

How complicated is WolframTones inside?
The core is simple, but there's a lot of sophistication in the details. There are many complex search criteria used in finding appropriate rules. Then there are style-dependent topological algorithms that pick out features of Rules to optimize roles of different Instruments, and create rhythms and harmonic progressions. The methods we're using are (so far as we know) essentially all new; most were invented as part of the project by Peter Overmann, who has a long history in computer music composition (and happens to be a senior executive at Wolfram Research).

What is the role of Mathematica in WolframTones?
It's the language and system in which WolframTones was developed, and it's what's used to run this site. (Specifically, the site is powered by webMathematica running on a collection of servers. Searches are done using gridMathematica.) Many symbolic language and pattern-matching capabilities of Mathematica are used for WolframTones. As well, of course, as its optimized CellularAutomaton function, and music and graphics Export function.

What are the historical antecedents of WolframTones?
Ideas of "generative music" or "algorithmic composition" go back a long way. Mozart, for example, was said to have a scheme for composing minuets based on throwing dice. In the early 20th century, composers like Schoenberg considered formal matrix-like methods, and especially in connection with early synthesizers there was interest in deriving music from electronic and other physical processes. In the late 20th century, many experiments were done using 1/f noise, fractals, L systems, and even cellular automata. Most often, explicit randomness was taken as the foundation, and extensive layers of post processing were done. The publication of A New Kind of Science led to a new approach, and much purer ways to derive music from the computational universe--culminating in WolframTones.

What is NKM?
It stands for "New Kind of Music." It's an analog of NKS--which is derived from the title of Stephen Wolfram's book A New Kind of Science.

Are cellular automata related to cellular phones?
No! It's just a coincidence of terminology. Cellular automata consist of discrete elements called "cells," while cellular phone networks consist of regions called "cells" served by single transmitters. Strangely, additive cellular automata are actually used in CDMA technology for phones. One day cellular automaton rules may well be used to control cellular phone networks--but we'll leave that confusion for later.

What is the "computational universe"?
It's the universe of possible computer programs. Programs have traditionally been complex artifacts created to for specific tasks. A key idea in Stephen Wolfram's A New Kind of Science is to think abstractly about all possible programs. What is then remarkable is that even among simple programs--that can for example be specified by short numbers--there is already rich and complex behavior. Exploring the abstract universe of these simple programs opens up many important new frontiers. There isn't anything that requires the programs to be computer programs: they're really just sets of abstract rules. But these days we're most familiar with such things in the context of computers.

Do WolframTones ideas apply to things other than music?
Absolutely! There are an amazing range of emerging applications of the ideas in A New Kind of Science to science, technology, medicine, the arts, etc. The visual arts and architecture are two areas closely related to WolframTones.

How can I learn more about ideas behind WolframTones?
Read Stephen Wolfram's book A New Kind of Science! It's very accessible, and it's available in most major bookstores and libraries, or on the web. You can ask questions on the NKS Forum. The Wolfram Technology Conference will also feature a special track about WolframTones. And each year, a select group of students are accepted to the NKS Summer School.

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