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Open in new tab Preprint from The Structure of Style: Algorithmic Approaches to Understanding Manner and
Meaning, Shlomo Argamon, Kevin Burns, and Shlomo Dubnov (Eds.), Berlin: Springer-Verlag,
2010, pp. 45-58.
Style in Music
Roger B. Dannenberg
Because music is not objectively descriptive or representational, the subjective qualities of music
seem to be most important. Style is one of the most salient qualities of music, and in fact most
descriptions of music refer to some aspect of musical style. Style in music can refer to historical
periods, composers, performers, sonic texture, emotion, and genre. In recent years, many aspects of
music style have been studied from the standpoint of automation: How can musical style be
recognized and synthesized? An introduction to musical style describes ways in which style is
characterized by composers and music theorists. Examples are then given where musical style is
the focal point for computer models of music analysis and music generation.
Carnegie Mellon University
5000 Forbes Avenue
Pittsburgh PA 15213 USA
rbd@cs.cmu.edu
http://www.cs.cmu.edu/~rbd/
Computers are important in many aspects of music composition, production, distribution, and
analysis. In contrast to domains such as natural language, speech, and even images, music rarely
has a well-defined meaning, referent, or objective. Consider the sentence, “Tie your shoes.” There
is a basic, objective meaning that forms a well-understood command (at least to English-speaking
humans). With spoken text and in different contexts, one can imagine all sorts of nuanced versions
expressing anger, sympathy, embarrassment, impatience, authority, gentleness, and so on.
Now consider a short melody without words. There is no obvious objective meaning, story, or
referent associated with a pure melody. Everything that we enjoy (or not) about the melody has to
do with expectations, sound quality, performance nuance, and musical texture. Essentially every
aspect of the melody that communicates something to the listener is an aspect of style.
In that sense, style is everything in music. So music is a wonderful domain to think about style, but
at the same time, style is so broad and vague that we will only make progress if we deconstruct
style into more specific concepts. As one might hope, music theory and the many dimensions of
music orchestration and performance offer many opportunities to investigate style. In addition to
theoretical writings, there are many stylistic concepts that have been modeled with computers and
studied more objectively.
In the next section, we will discuss the nature of style in music and talk about how one might
describe or characterize musical style. This section is written for the musical novice. If you “don’t
know anything about music but you know what you like,” perhaps this section will offer some
terminology and help to understand how musicians think about music structure and organization as
it relates to style. Section 2 presents a number of computer models of style for both analysis and
generation. This section will assume some general knowledge of computer science including data
structures, and algorithms.
What Is Musical Style?
In general, “style” means a distinctive quality, form, or type. A more specific definition that
certainly applies to music is “a particular manner or technique by which something is done, created,
or performed.” (Merriam-Webster 2007) In music, the term “style” is used in many ways:
• Historical periods of music are associated with styles. For example, we might say a
composition by Mozart is in the Classical style, and one by Bach is in the Baroque style.
These styles can be more or less specific: in the recording industry, the term “Classical” is
so broad that Mozart and Bach are both “Classical” composers, but a music scholar might
speak of “late Classical” or “Neapolitan Baroque.”
• Styles are associated with composers. We can speak of composing in the style of
Beethoven. In this sense, “style” means “a set of characteristics generally found in the
works of a particular composer.”
• Performers, especially improvising performers, also have styles. The “ballad style of Miles
Davis” refers to characteristics of Miles Davis’s performances of ballads. Of course, great
classical music players interpret music they perform even if the music is not improvised.
One can speak of the expressive style of Itzhak Perlman, for example.
• Style can refer to aspects of musical texture. “Texture” is one of those words like “style”
that is very difficult to pin down, and dictionaries do not consider the depth of meaning that
texture has for composers. Basically, musical texture is a composite of many aspects of
music that one would hear within a second or so. On longer time scales, melodic, rhythmic,
and harmonic progressions stand out, but at shorter time scales, we hear timbre (violins?,
electric guitars?, saxophones?), very short repeated patterns, many or few different pitches,
loudness, and brightness, all of which give a subjective impression we call texture. While
composers usually consider “texture” to be something different from style, texture is at least
a closely related concept. “Texture” usually refers to sound and the activity of making
sound, while “style” is most often used to describe the general impression or intention
provided by a texture. We speak of a “tonal style,” a “heavy style,” or a “big band style,” all
of which refer to texture-induced impressions. In these examples, the style is not so much
the melody, rhythm, or harmony, but the sound color in which these elements are
embedded.
• Music is often described in emotional terms: exciting, soothing, calm, scary, etc. Sometimes
music causes listeners to experience emotions, and other times the listener may recognize an
emotion without necessarily experiencing it. Either way, emotional associations are yet
another way to describe the style of music.
• Style is often used to mean “genre,” yet another difficult-to-define term. A genre is a
category of music characterized by a particular style, but a genre can also be influenced by
social conventions, marketing, association with a particular artist, and other external
influences. Still, it is common to refer to something as “rock style,” or “bebop style.”
All of these definitions are related to the underlying idea that there are important characteristics of
music that we perceive as common or related across certain collections – the work of a composer,
the output of some historical period, or music of some genre. Musicians study the elements of
music in detail and are familiar with ways in which these elements can be varied, giving rise to
different styles. It is interesting that non-musicians can also perceive styles with great sensitivity,
often with no ability to describe characteristics or differences. For these listeners, I will offer some
terminology and discussion through examples. Do not expect to become a musical expert, and do
not believe that experts have a complete formal model of style, but hopefully this discussion will
explain some of the ways musical style can be treated objectively. For more details on music
terminology, concepts, and history, the New Grove Dictionary of Music and Musicians (Sadie and
Tyrrell, 2001) is an excellent reference.
An Example: Baroque vs. Classical Style
A good way to learn about musical style is to examine the differences between two well-known
styles. In this section, we will compare Baroque and Classical styles. The Baroque period extends
from about 1600 to 1750 and includes music by Monteverdi, Bach, Handel, and Vivaldi.
As noted above, “classical” is sometimes used to refer to a broad range of styles sometimes referred
to as “Western art music,” which includes Renaissance, Baroque, Classical, Romantic, and many
modern styles. But to experts, Classical music is music from the Classical period, approximately
1750 to 1800. The most celebrated Classical composers are Haydn, Mozart, and Beethoven in his
early years.
Baroque and Classical music differ along many dimensions as listed in Table 1. It should be noted
that there are few absolutes in music, and certainly there are exceptions to every rule. However,
scholars generally agree that the characteristics described here are important, real differences
between the two styles. These differences are now presented in more detail.
Table 1. Characteristics of Baroque and Classical Styles
Baroque
Contrapuntal
Ornamented
Frequent, less meaningful modulation
Single vivid feeling
Constant intensity throughout
Classical
Homophonic
Internal Structure
Modulation becomes structural element
Range of emotions
Dramatic climax and resolution
The first difference is contrapuntal vs. homophonic writing for multiple voices. Here, “voice” is
used in a technical sense that means a human voice or an instrument, so the difference is how
composers combine multiple simultaneous sounds. Homophonic writing emphasizes harmony and
a single dominant melody. Typically, the highest voice carries the melody, and concurrently with
each melody note, the other voices sing harmonizing pitches. Most church hymns are homophonic.
In contrast, contrapuntal writing emphasizes melodic motion over harmony. It is as if each voice is
singing its own melody. Often one voice will sing a short melodic sequence and then hold a steady
pitch while another voice sings an “answer” in the form of another melodic sequence. Two, three,
or more melodies are thus intertwined to create what is called counterpoint. In more objective
terms, at least one feature of contrapuntal writing is that fewer notes begin synchronously
compared to homophony.
In Baroque writing, there is an emphasis on ornamentation, typically short, fast notes inserted
above and below at the beginning of a “normal” note in the melody. The trill, where the pitch
alternates between the melody note and the next one above, is another ornament. Some ornaments
and their interpretations are illustrated in Figure 1. If Baroque style tends to “decorate” melodic
lines, the Classical style is plainer, with an emphasis on developing ideas and formal structure. For
example, the sonata form that appears in the classical period is based on a structure consisting of
two themes, their development, a return to the themes, and a conclusion.
Figure 1. Some musical ornaments and their interpretations: Turn (left) and Mordent (right).
Baroque and Classical music is based on musical scales. For example, the white keys of the piano
(omitting the black ones) are used in the scale of C-Major. Any music can be transposed by adding
an offset to each piano key. For example, if every note is played 7 keys to the right on the keyboard
(counting white notes and black notes), the result will sound very similar, but the music has been
translated to a new location. This is called a modulation. Modulation in Baroque music occurs
frequently, but the modulations do not have much significance. In Classical music, modulations are
often carefully resolved: a modulation up 7 steps is likely to come back down 7 steps, setting up an
expectation in the listener. In the sonata form, modulation is used to announce the introduction of
the second theme, and modulation is often carefully coordinated with other musical structure.
In terms of feeling, Baroque music typically portrays a single emotion at least through an entire
movement or major section of a composition. Classical music is more likely to progress from one
feeling to another in a narrative style, exploring a range of emotions. While Baroque music is more
likely to maintain a feeling with a steady intensity, Classical music often develops into a climax of
tension, excitement, and just plain loudness, and then settles into a state of calm and resolution. We
will consider later how something as abstract as “feeling” in music can be quantified and studied
objectively.
To summarize, Baroque and Classical music differ along a number of dimensions. These
differences can be difficult to formalize and even to describe to non-musicians, but at least it should
be clear that most music lovers, with a little experience, can at least recognize these styles. Music
scholars can go further by describing differences in specific terms. Music is one area where “style”
has been deeply studied and where there are many examples and analyses of different styles.
Style in Popular Music
What makes a modern popular musical style? There are so many emerging styles that most people
are not even familiar with many of them. What distinguishes Black Metal, Death Metal, Doom
Metal, Hair Metal, and Power Metal? (Hint for Classical purists: these are rock styles.) And if you
are a hard-core metal enthusiast for whom these terms are familiar, what distinguishes Be-Bop,
Hard-Bop, and Post-Bop? (Hint: think jazz.) Rather than tackle these questions specifically, we will
look at some general characteristics of music. Style, especially in popular music, includes an
important sociological component, so we should not expect style to be purely a matter of how
something sounds. The composer, performer, geographic region, marketing, and public perception
have an important influence on how music is categorized.
As always, popular music style has many meanings and interpretations. We could talk about
singing style, genre, rhythmic feel, dance styles, and others. Without getting too specific, imagine
scanning a radio dial looking for a favorite style of music. Experiments by Perrot and Gjerdigen
(1999) indicate that we can recognize style in a fraction of a second. What elements of music allow
us to quickly determine if we have found something in the style we are looking for?
In popular music, one very important element is the instrumentation. If we hear nothing but guitar,
bass, and drums, this might be hard rock, but if we hear a saxophone and trumpet, this might be a
blues band. Strings might indicate pop music or a rock ballad. In addition to instruments, the
quality of instrumental sounds is important. An acoustic guitar or pure guitar sound might indicate
soft rock or country music, while a highly distorted electric guitar is more typical of heavy metal.
As we shall see, automatic genre classifiers can be based purely on the average frequency spectrum
of music audio.
Vocal quality and the number of vocalists (with harmony) also tell us something. Steady clear
vocals, spoken words (as in Rap), screaming, falsetto singing, and the use of pitch inflections and
vibrato could all be described as vocal styles, and all tell us something about the style of music.
You would not hear an operatic voice singing country music or four-part harmony singing on a
techno track.
Rhythm is very important because most popular music is very rhythmic. There are rhythmic
patterns associated with different styles of music as well as with dance styles. Rock is characterized
by strong beats in groups of four, with accents on 2 and 4: one-TWO-three-FOUR. Compare this to
Reggae, which also follows the general rock pattern, but often with a slower tempo, a subdivision
of beats (e.g. one-and-TWO-and-three-and-FOUR-and), and emphasis on the rhythmic bass
patterns. Reggae is a good example of the importance of not only the rhythm but how the rhythm is
established by different instruments including different types of drums and other percussion.
Computational Approaches to Music Style
In recent years, many advances have been made in the analysis of musical style and the generation
of music according to certain styles. Some of these advances can be attributed to advances in
statistical machine learning, which seems to be well-suited to the capture of style information
where data is more representative of trends than hard-and-fast rules.
Learning to Recognize Improvisational Styles
A standard task is a forced-classification of music into one of a set of style categories. The general
approach is seen in Figure 2. The input is music data in the form of audio. The first step is to
extract features from the audio signal. While it is theoretically possible that a system could learn to
classify styles directly from digital audio signals, this is not practical. Instead, we perform some
analysis on the sound to obtain a small set of abstract features that will hopefully contain useful
information for discriminating styles. Next, a classifier is used to estimate the style of the sample.
The classifier can be based on any number of machine learning models. For this discussion, we will
only be concerned with the general nature of these systems. Basically, a classifier begins with a
number of labeled examples called the training set. Each example contains a set of features
obtained from an excerpt of music and a label, which gives the correct style for this excerpt. There
may be many thousands of examples. From the examples, the classifier learns to output the correct
label given a set of feature values. Learning is usually accomplished by iteratively adjusting