How We Sing: The Science Behind Our Musical Voice. Music has been an important part of culture throughout our history, and vocal

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1 Illumin Paper Sangmook Johnny Jung Bio: Johnny Jung is a senior studying Computer Engineering and Computer Science at USC. His passions include entrepreneurship and non-profit work, but he also enjoys singing in his free time as a baritone voice. Keywords: music, singing, acoustics, sound Multimedia Suggestions: An animation of how the lungs project air through the larynx and out of the body, an interactive demo where you can control the vibration of the vocal cords and create different pitches, an animation of how the larynx vibrates when air passes through it, a demo allowing a user to see differences between sounds with varying larynx sizes, and various qualities of the vocal cords Abstract: The process of singing is a very physical process that starts with the vocal cords. The vocal cords (also known as vocal folds) are located in the larynx and vibrate when air passes through them. These vocal cords can be controlled with muscles in the larynx and can vibrate at specific fundamental frequencies to create musical notes. Differences in vocal cords and larynxes can result in important differences in vocal range and vocal qualities, as the physical properties of a person s vocal structures can make all the difference in how well a person can sing. How We Sing: The Science Behind Our Musical Voice Music has been an important part of culture throughout our history, and vocal pieces are no exception to this. Great singers have come and gone, but have persisted throughout history from early operatic pieces in the Classical era to jazz-inspired Frank Sinatra love songs in the 20 th century. Every person has the innate ability to sing and produce music using his or her own vocal cords, but interestingly enough, the quality of singing varies greatly from person to person. This brings up a question that some people might think they have an answer to: What makes someone a good singer? Obvious answers to this include vocal range, pitch and the loudness of sound. In this article, we will challenge some misconceptions about singing and dive deeper into some of the

2 physiological features that allow singers to produce sound, and explore why some voices sound better than others. We will begin by exploring how our bodies produce singing and sounds using our vocal airways. A sound is produced through what could be thought of as two different processes. The first is where the sound and pitch is created through our body s voicebox, and the second is where this sound is then passed through a filter (i.e. tongue, mouth, lips) that then modifies this sound [1]. Figure 1 shows a drawing of the vocal structures in the body, and how the sound will pass through from the trachea (windpipe) through the mouth and out into the world. Figure 1: View of vocal structures in the body [1] The first process starts when air is expelled from the lungs through the trachea (windpipe) in the larynx (at the bottom of the Figure 1). The vocal folds (also known as vocal cords) are muscular tissues that lie on the larynx. These vocal folds cover up parts of the airway

3 and will allow for small bits of air to pass through [1]. In fact, when someone sings, these vocal folds will close slightly, and a breath from the lungs will then push against the vocal cords. Vibrations will then start to occur which will allow small puffs of air to escape out above the larynx [2]. These vibrations occur when we get the right air pressure and position of the vocal cords, and when done right, these vibrations will vibrate at acoustic fundamental frequencies, i.e. musical sounds [1][3][4]. Now singing is only worth listening to if we can control the frequencies at which the vocal cords can move. Unfortunately, we have no direct control over this process, as we cannot simply adjust the frequency of the vocal cords. Luckily, muscles in the larynx can help us get the desired sound we want by controlling how these folds are pushed and positioned [1]. The thyroid cartilages or Adam s apple (as seen in Figure 1) that surround and support the vocal folds and the arytenoid cartilages in the larynx can be controlled using muscles and draw the vocal folds together and close off airflow. Additionally, these vocal folds can be changed in length and tension, and by holding this in a steady, repeating pattern, we can generate sounds at specific frequencies [1][3][4]. Once we have sound, the next step is to change that sound to different notes, i.e. pitch. We can achieve pitch through the control of the fundamental frequency of the vocal cords. Fundamental frequency itself refers to how fast the vocal cords are vibrating in a time interval. For speech, the fundamental frequency varies between 100 and 400Hz, meaning that the vocal folds will vibrate 100 to 400 times a second [1][4]. In Figure 2 below, we can see that a scale of notes (from C4 to C5) has frequencies that correspond to each note.

Figure 2: Musical notes and their corresponding fundamental frequencies Source: Wikimedia Commons (http://upload.wikimedia.org/wikipedia/commons/6/65/frequency_vs_name.

4 Figure 2: Musical notes and their corresponding fundamental frequencies Source: Wikimedia Commons ( By vibrating the vocal cords at different frequencies, we are able to produce different pitches, and move onto the production of music using our vocal airways. From Figure 2 we can see that as we move up the musical scale (and the notes get higher), the frequency increases as well. Muscles in the larynx need to be able to control the vocal cords to achieve different frequencies and this is achieved by lengthening the vocal folds. When the vocal folds are lengthened, the vocal folds themselves becomes thinner, and a higher pitch results as vibrations are now more frequent [2]. Finally, once the pitch is created in the larynx, air now flows upwards (as shown in Figure 1) into the mouth and nasal cavities. Here we have a filter that interacts with the existing sound, which can then be modified by the geometry of the mouth and the positions of the tongue and various structures. All of this influences not only the sound, but can also affect the vocal cords

5 themselves. This is also how different vowels and consonants are created in our singing and speech [1][4]. For example, making an o ring shape with our mouth will make it easier to verbalize the vowel o. What is important to note is that singing is a physical activity with many parts and pieces, and that many vocal structures are working in unison to produce a given note [4]. Now that we know that how pitch is produced, we will now explore the differences between people in singing and figure out why some people are better at singing than others. One key attribute that many people claim to be a great part of singing is the vocal range. The vocal range is the full range of notes that a singer can comfortably sing at, and larger vocal ranges are often praised as they can allow for greater musical expression [2]. Vocal range comes from the size of the larynx itself, with smaller vocal folds resulting in higher fundamental frequencies. Higher fundamental frequencies mean that the vocal cords will vibrate faster and produce higher notes. Women and children in particular will have faster vibrations of their vocal folds and have higher vocal ranges than men. Interestingly enough, this explains the drastic change in vocal range that many men have when they hit puberty: the size and mass of their vocal folds increases significantly which results in a drop in fundamental frequency [3]. One aspect of vocal ranges that is important is the presence of registers, i.e. modes of vibration of the vocal cords. In a normal state, the vocal folds will vibrate in their entirety. This is a low register as it is causes the vocal cords to have higher amplitude (greater volume) and lower fundamental frequencies (lower notes). This is often known as the chest register as it tends to produce feelings of vibrations in the chest [1][2]. The register that people love to hear is falsetto, which is a breathy voice that

6 stretches beyond the normal vocal range. Falsetto occurs in men when only parts of the fold vibrate, and looking at the science of this, we can see that falsetto will tend to create softer and higher notes, with higher fundamental frequencies. The differences between the two modes is quite stark in its operation, and the best professional singers work very hard to hide the transition between these two modes in pitch and intensity (it s often very noticeable) [1]. Of course, pitch isn t really what defines the best singers! Voice quality is usually what is more important, as we desire certain artistic qualities to pitches. This is achieved through (yet again) the control of the vocal cords. Vocal cords not only control pitch but they also control how the air flows through the larynx. In Figure 3, we now look at a topdown view of the larynx and can see how the thyroid cartilage can control the vibrations of the vocal folds. Figure 3: Top-down view of larynx [1] The thyroid cartilage and arytenoids are muscles that control the airflow through the larynx. In a breathy voice, the folds will not meet together and air will continue to flow

7 on. In creaky voices, the vocal folds will close too tightly which will result in irregular cycles of vibrations (and terrible sounds). A lot of the quality of the voice will come from how the larynx and structures in the larynx (as shown in Figure 3) interact with the air coming through from the lungs. Additionally, a lot of the artistic quality can be found through the presence of vibrato, which is the pulsation of pitch usually accompanied with synchronous pulsations of loudness and timbre, of such extent and rate as to give a pleasing flexibility, tenderness and richness to the tone [2]. A good vibrato will tend to have five to eight regular pulsations per second, and this is controlled by the muscles in the larynx. In effect, singing is a physically demanding process, and it makes sense that some people cannot produce any sound at all, while others can fill an entire concert hall with their singing. From what we ve learned, producing notes with our vocal structures is a physically demanding process, and one may make the conclusion that the best singers are born with god-given physical features that allow them to sing better than the rest. This conclusion is hotly contested and even professional singers themselves disagree on this point. Some believe that great singing comes from innate talent and that god-given physical features are necessary for one to be a great performer [2]. This may be the case, as we idolize some great singers, as they have almost inhuman-like vocal ranges and vocal qualities. However, others find that regular practice and instruction is just as important in the development of great singers. One may argue that a great singer could be born with better breathing and singing mechanisms than others. However, interestingly enough, research has shown that this does not differ between singers and ordinary people in regular speech. Respiratory strategies between singers and non-singers only differ in

8 singing, which seems to suggest that great singers take the time to develop the most optimal strategies to singing, which could be facilitated through training and instruction [5]. Regardless of whether singing can be developed over time or is more defined by existing physical features (and it s probably both), it is interesting to see how the simple presence of vocal cords in the larynx gives people the ability to produce various pitches and express themselves vocally and musically

9 References [1] J. Wolfe et al. Voice Acoustics: An Introduction [online]. Available: [2] M. Bunch Dayme, Dynamics of the Singing Voice, 5 th ed. New York: SpringWienNewYork, 2009, ch. 8-9, pp [3] UCL Psychology & Language Sciences. Acoustics of Speech and Hearing Lecture 2-1: Voice Quality [online]. Available: [4] J. Sundberg, The Acoustics of the Signing Voice, Sci Am, vol. 236, no. 3, pp. 82-4, 86, 88-91, Mar [5] W.S. Brown Jr. et al., Physiological Differences Between the Trained and Untrained Speaking and Singing Voice, Journal of Voice, vol. 2, no. 2, pp , 1988.

Glossary of Singing Voice Terminology

Glossary of Singing Voice Terminology Adduction The closing action of the vocal folds. The opposite of abduction, or opening. Adolescent voice change The changes within the voice, in both boys and girls,