2.1: The Dimensions of Sound

Whether we are listening to noise or music, we will perceive the same elements: rhythm, pitch, volume, articulation, and timbre. These elements will combine in time to produce a sonic object of a given texture that either exhibits or lacks form. In the following sections, we will define each of these dimensions and explore the roles that each plays in the creation and perception of music.

Rhythm

Rhythm is the temporal aspect of sound. It is the pattern of “on” and “off” states exhibited by any sound as time passes. Rhythm is by no means unique to music. When you speak, the consonants of your words produce rhythm. When a car drives by, the oscillating sounds of the tires and engines create rhythm.

Music often (although not always) features rhythmic patterns. The most basic of these is the pulse, which—like the pulse produced by your own heart—is a sequence of regularly-spaced sounds. The frequency of the pulses determines tempo, which can range from very slow to very fast. It makes sense that music should tend to be organized around a pulse, since our very existence is organized around pulses. Our hearts beat to a pulse, we often breathe to a pulse, we walk to a pulse, and we organize time into pulses (seconds). It is usually not difficult to detect the pulse in a musical work: simply tap your foot or clap your hands, and there it is.

Video 2.1.1 : This video demonstrates pulse.

Pulses, however, are usually not all of equal weight. Some have a greater musical significance than others. When pulses are organized into groups containing strong and weak beats, meter is established. Each metrical group is called a measure or bar. In notated music, these groups are physically separated by bar lines, which help performers to easily perceive how the pulses are grouped and to identify which is the strongest. While measures can contain any number of pulses, the most common grouping are two, three, and four. These groupings are termed duple, triple, and quadruple meter. Each measure in all three of these meters will begin with a strong pulse, termed the downbeat. In duple meter, the pattern of pulses is [strong-weak]. In triple, it is [strong-weak-weak]. And in quadruple, it is [strong-weak-medium-weak].

Video 2.1.2 : This video demonstrates tempo

Pitch

Pitch refers to the “highness” or “lowness” of sound. Sound, of course, is not physically located in high or low spaces, but most listeners can easily perceive the difference between a high-pitched sound and a low-pitched sound. Our use of the terms high and low to describe pitch reflects the characteristics of sound waves.

Figure 2.1.2 : This video introduces the concept of pitch in the context of a familiar melody.

All sounds are produced by vibrating bodies, which in turn produce sound waves that can be perceived by mechanisms in your ear and decoded by your brain. Pitch is determined by the frequency of those sound waves. A high pitch is produced by a high-frequency sound wave, and a low pitch is produced by a low-frequency sound wave. The frequency of sound waves is in turn determined by the characteristics of the vibrating body that sparks them into action. All other parameters being equal, a long string, once plucked and set into motion, will produce a lower pitch than a short string. Likewise, a thick string will produce a lower pitch than a thin string of the same length. The same principles apply when you blow across the ends of tubes, strike bells, or beat drums: the larger, longer, and heavier the vibrating body, the lower the sound it will produce.

Interactive Element

This online oscilloscope allows you to visualize sounds. Pitch is reflected in the distance between waves, which will decrease as pitch level increases. Volume is reflected by the size of the waves, which will grow in amplitude as dynamic level increases.

Video 2.1.3 : This video demonstrates the relationship between pitch frequency and wave form tubes, strike bells, or beat drums: the larger, longer, and heavier the vibrating body, the lower the sound it will produce.

Music is usually characterized by the careful organization of pitches. To begin with, most musical systems recognize what is termed octave equivalence. This is the consensus that you can halve or double the frequency of the pitch without changing its essential identity. To see this principle in action, attend any birthday party at which both women and men are present. When the guests sing “Happy Birthday,” they will not sing exactly the same pitches. Instead, the women will tend to sing in a high octave, and the men will tend to sing in a low octave. In technical terms, this means that the women will probably sing pitches that have frequencies equal to twice that of those sung by the men. However, all participants will agree that they are all singing the same pitches, or in unison. An octave is an example of an interval, which is the distance between two pitches.

Video 2.1.4 : This video demonstrates octave equivalence in the context of “Happy Birthday.”

6.

7. This video introduces the concept of melodic range.

In the Western system, we acknowledge this phenomenon by using the same letter names to designate pitches in different octaves. For example, pitches at the frequencies of 110 hz, 220 hz, 440 hz, 880 hz, and 1,760 hz are all called “A.” However, specific frequencies are still important. Music that contains mostly high pitches has a different effect on listeners than music containing mostly low pitches, even if the rhythms and sequence of pitches are the same. Additionally, melodic range (the distance between low and high pitches) and changes in register (the use of high or low pitches) can be important musical elements.

The Western system—that is to say, the system of musical organization that was first developed in medieval Europe and continues to dominate global listening today—goes quite a bit further in its efforts to organize pitch. Let us return to the octave. Between the A at 220 Hz and the A at 440 Hz, there are a near-infinite assortment of possible frequencies at which an intermediary pitch might sound. However, we do not use all of those pitches when we create music. Instead, we identify a limited number of specific pitches to be used. The Western system is best represented by the piano keyboard, which is both familiar and useful.

Figure 2.1.1 : Each white key on a piano is assigned a letter name. Those letter names repeat at each octave, reflecting our agreement that every A (for example), whether high or low, is in some sense the “same” note. The black keys are named after the adjoining white keys: simply add “flat” to the name of the white key to the right or “sharp” to the name of the white key to the left. Source: Public Domain Pictures Attribution: Karen Arnold License: CC0

8. This video demonstrates the chromatic pitch set.

9. This video demonstrates a major scale.

As you can see, the space between the A at 220 Hz and the A at 440 Hz is divided across twelve piano keys. This is called the chromatic8 pitch set, and it includes all of the pitches used in Western music. However, composers only rarely use the entire chromatic pitch set. When you do hear music that uses every available note, you will probably find that it makes you uncomfortable. This is because we are used to hearing music built using a set of only seven pitches that is called a scale. Most music is based on one of two scales: the major scale9 and the minor scale10. If the pitches in a piece of music are drawn from a major scale, it is described as being in the major mode. Likewise, if the pitches are drawn from a minor scale, it is in the minor mode. A scale can start on any pitch, which then determines the key of music that is based on that scale. For example, music created using pitches drawn from the A major scale is in the key of A major.

10. This video demonstrates a minor scale.

11. This video demonstrates the melody to Beethoven’s “Ode to Joy.”

12. This video demonstrates melody and a possible harmony to Beethoven’s “Ode to Joy.”

13. Here, you can hear Beethoven’s melody and harmony in the context of his original composition.

14. This video introduces the concept of melodic shape.

15. This video introduces the concept of melodic motion.

In most pieces of music, pitches are assigned to two different roles: melody and harmony. Melodies are constructed out of a sequence of pitches. This is the part of a musical work that you might sing along with or that might get stuck in your head. Melodies have various characteristics, including shape and motion, which can be conjunct (in which the melody primarily moves up and down the scale) and disjunct (in which the melody contains larger intervals and leaps). Harmonies are constructed out of groups of pitches that are usually sounded simultaneously and constitute chords, while a sequence of harmonies is termed a chord progression. In a musical work, the harmony is usually unobtrusive and might be repetitive. A melody and a harmony sound good together when they are based on the same scale and contain some of the same pitches. However, every melody can be harmonized in many different ways, using various chords. Likewise, a single harmony can be used to accompany many different melodies.

16. This video demonstrates chords, which are used to harmonize melodies.

Although this text will not offer a technical explanation of harmony (which can become very complicated indeed), it is often central to the listening experience. A certain chord progression can surprise you, or excite you, or break your heart. It is not necessary to understand harmonies from a theoretical perspective to feel their impact. You also don’t need a theoretical background to understand the role harmony plays in establishing and then satisfying or frustrating expectations. As long as a piece of music is in a key, one chord—the chord built on the note that the key is named after—will serve as a home base, while other chords in the key will facilitate journeys away from or back towards that home base. We get used to hearing certain chord progressions and come to expect them, so we often have a sense of where the music is going to go. If we hear an unexpected chord or—most shocking of all—a chord that is not in the key of the piece of music, we tend to respond emotionally.

Volume

Like pitch, volume—the loudness or softness of a sound—is a parameter of every soundwave. Volume is determined by the amplitude of the wave, such that waves with a large amplitude produce high-volume sound and waves with a small amplitude produce low-volume sounds. While volume is simple to understand and assess (we can all tell whether music is “loud” or “soft”), its significance in the creation of musical meaning cannot be overlooked. On the one hand, certain genres of music depend on volume for their identity. You cannot appreciate the impact of heavy metal by listening to it with the dial turned down, just as you cannot sing a baby to sleep at the top of your voice. Changes in volume can also communicate meaning in music. A gradual increase in volume can indicate growing excitement, while a sudden change in volume can indicate a dramatic mood shift.

A few terms will help us to talk about volume, which is also referred to as dynamic level. An increase in volume is referred to as a crescendo, while a decrease is termed a decrescendo or diminuendo. Musicians in orchestras, bands, and choirs describe volume using Italian terms including fortissimo (very loud), forte (loud), mezzo forte (medium loud), mezzo piano (medium soft), piano (soft), and pianissimo (very soft). While this book will not employ these terms, you might encounter them elsewhere.

Articulation

Articulation has to do with how pitches are begun, sustained, and released, and it is driven primarily by changes in dynamic level. In music production language, this dimension of sound is referred to as the envelope. The envelope is independent of pitch, but it determines the character of that pitch. For example, a pitch might begin with a gentle increase in volume, or a sudden decrease, or no dynamic change. Once it has begun to sound, a pitch might be sustained for a long time, or it might be abruptly cut off. And when it is ended, it might be released with a decrease in volume, and increase in volume, or no dynamic change.

17. This video explains the four elements of the envelope: attack, decay, sustain, and release.

Although the preceding description was highly technical, the effects of articulation are easy to perceive. At one end of the spectrum, a series of pitches might be heavily punctuated, with forceful onsets and no sustain. The traditional Italian term for this articulation is staccato—a term that means short and accented, and which is difficult to replace with an English equivalent. At the other end, a series of pitches might be smoothly connected, with gentle onsets and a great deal of sustain. The term for this articulation is legato. Between these extremes are an enormous variety of approaches to beginning, sustaining, and releasing notes, many of which are unique to the instruments that produce them.

Timbre

The final characteristic that is universal to all sounds is timbre (TAM-ber), which describes the quality of a sound. Whether one has no musical training or is an accomplished performer, we are all skilled at identifying minor variations in timbre. This ability lets you know that your mother is calling you from the other room, not your sister. It helps you to tell the difference between a guitar and a piano. Not only does every voice and every instrument exhibit a unique timbre, but performers can alter the timbre they produce by changing their technique. Timbre is also integral to genre and style: A symphony orchestra produces one range of timbres, while a rock band produces another.

Variations in timbre are made possible by the existence of the overtone series, which is a sequence of higher-pitched frequencies that are activated every time a pitch is produced. When you strike a key on the piano, for example, you are not only sounding the pitch associated with that key, you are also activating dozens of pitches at set intervals above that pitch, each of which might sound at a relatively high or low volume. The combination of these overtones produces timbre. Two instruments playing the same pitch sound different, therefore, because they are activating different pitches in the overtone series at different volumes. The complexity of this process allows for near-infinite variety in timbres.

Figure 2.1.2 : These are the pitches of the overtone series as they might be notated on a staff. Even if you cannot read notation, you can see that the pitches get closer together as they get higher. When one plays a low C on any instrument, most of these pitches are sounded to some degree. The pitches in blue will be out of tune. Source: Wikimedia Commons Attribution: User “Hyacinth” License: CC BY-SA 3.0

If you engage with every example in this volume, you will experience an extraordinary range of contrasting timbres. Audiences for various genres develop unique preferences and expectations for timbre, and timbre is often one of the most distinctive characteristics of a musical tradition. Variations in timbre are often not hard to identify: A piano trio, for example, had a different sound quality than a thrash metal band. These differences, however, can be very difficult to put in to words. While timbre is easy to perceive and measure, it is hard to describe.

For the most part, we will consider timbre in the context of individual examples. We will investigate different ways of producing sound with the human voice (which is capable of extraordinary diversity), the various instruments that are responsible for the characteristic sounds of non-Western classical traditions, and the electric instruments and sound processing techniques that have contributed to popular music of the last seventy years. There is one sound source in particular, however, that pervades this volume: the symphony orchestra. For an overview of the instruments that make up the orchestra, please see Appendix A.

Texture

We are now really to move from sound to music, which usually exhibits some additional characteristics. One of these is texture18, which concerns the contents of and interactions between various layers or voices in a musical work. We use four basic terms to describe texture, although these terms can tell us little about what a piece of music actually sounds like. Monophonic music has a single melody line, performed by a soloist or in unison, with no accompaniment. If you add an accompaniment that has different pitches (probably chords) but that is secondary to the melody, you have homophonic music. In polyphonic music, every voice is independent but equally important, and there is no distinction between melody and harmony. And in heterophonic music, multiple instruments or voices each perform a unique version of the same melody, such that unison is not achieved. We will encounter these terms in the context of specific examples throughout this volume.

18. This video introduces the concept of texture.

19. This video explores variation in texture.

In addition, texture can be described using qualitative terms. It can be thick or dense, meaning perhaps that there are many independent and highly-active parts, or it can be thin or sparse, meaning perhaps that there are few instruments, each of which can be clearly identified and tracked. Consider, for example, two songs from Sgt. Pepper’s Lonely Hearts Club Band, discussed in Chapter 8. The concluding thirty seconds of “Being for the Benefit of Mr. Kite” are irrefutably dense: There is so much going on that it is difficult to identify individual sources of sound, and the listener’s focus is constantly attracted by new and varied voices. The first verse of “A Day in the Life,” on the other hand, has a thin texture, made up only of guitar, bass, and shaker. It is possible to focus on individual instrumental parts and to hear the unique articulation of each.

Form

Finally, we need a way to talk about how music unfolds over time. This element is known as form. Most musical compositions exhibit formal characteristics, although some pieces are very amorphous or difficult to describe in terms of form. At the very least, creators of music usually plan the formal dimensions of their work. John Cage’s 4’33” doesn’t have form, per se, since its sonic contents are always different, but at least the composer decided how long the piece was going to last.

In most cases, the creators of music rely on three organizational principles that produce form. These are repetition, variation, and contrast. Repetition occurs when we hear the same thing twice, whether it is a long and complicated melody, a short melodic fragment, a rhythm, or a harmonic pattern. Variation occurs when musical material returns, but with alterations. Contrast, naturally, refers to musical material that has not been heard before.

Repetition is key to our ability to understand and enjoy music. When we hear something new, internal repetition allows the music to quickly become familiar and helps us to predict what is going to happen next. For this reason, all popular music features repetition of various kinds. When an unfamiliar song comes on the radio, you can expect to hear the chorus (the catchy part with words and melody that both repeat) several times. Most popular songs also have repetitive chord progressions and some sort of repeating accompaniment, known formally as an ostinato. Ostinatos are important in many types of music and will play a role throughout this book.

20. The bass line at the beginning of White Stripe’s “Seven Nation Army” provides a good example of an ostinato. This seven-note melodic figure is heard throughout the song.

Variation and contrast are what make music interesting. We enjoy and rely upon repetition, but we can only take so much. However, music that contains constant variation or lacks repetition altogether requires more of the listener. Most people cannot relax and enjoy music that is constantly changing and that offers something new and different with each passing moment. At the same time, such music can communicate a great deal and be particularly rewarding for an engaged listener.

The degree to which music relies on repetition or contrast is often linked to its purpose. Dance music, for example, tends to be repetitive. When people are dancing, they don’t want much contrast. They want the music to maintain a constant tempo, rhythmic character, and mood. Minor variations might make dancing more interesting, but major changes can make dancing impossible. In addition, when you’re dancing you don’t pay careful attention to the nuances of the music. Music belonging to a sung theater tradition, however, is much more likely to exhibit contrast. In the first place, it is probably being used to express emotions or to portray a nuanced character. Variation and contrast allow for more complex and meaningful communication. In the second, audience members are paying full attention to the music, and, therefore, have a higher tolerance for contrast and change.