Emily C., McKinney, Ch. 2

• What are the four elements essential to the existence of sound? (20)
• A vibrating object
• a power source to make the object vibrate
• a medium through which the vibrations are transmitted
• an apparatus to receive the vibrations.
• (a.k.a. vibrator, actuator/stimulus, transmitting medium, receiver
• How fast does sound travel? (20)
• 750 mph or 1,100 feet per second
• Explain elasticity (as applied to air molecules). (20)
• Molecules move about independently, and when they are forced closer together or apart, they will try to return to their original/starting state. When energy travels past air molecules, they are disturbed and are moved in whatever direction the energy is headed. Once the “wave” has passed, they return to their original positions. This pushes air molecules around in a chain reaction. 
• Explain compression/rarefaction waves. (20)
• A compression wave is the action of molecules being pushed together, and rarefaction is when they are being pulled apart. 
• Does the air actually move at 750 mph? (20)
• No; elasticity prevents the disrupted molecules from flying into space. Their movement passes the sound wave along, not the actual molecules. 
• Describe the two basic categories into which sounds are divided.
• Musical tone: the sound wave pattern repeats itself regularly. (a.k.a. recurrent form)
• Noise: Doesn’t have a recognizable pattern because of its irregularity and lack of order. (a.k.a. chaos)
• List and describe the five characteristic properties or essential elements of musical tone. (21-25)
• Duration: It’s just how long a musical tone lasts. 
• Intensity: It’s often associated with volume and loudness, but it’s the amount of energy in the sound; the strength of the sound. It can be measured by decibel level. The amplitude (how high the wave is) helps determine intensity. 
• Pitch: This is the frequency of vibration of a musical tone as expressed in the number of vibrations per second (measured in Hz). The faster the frequency, the higher the pitch (and vice versa). 
• Sonance: The pattern of change in timbre, pitch, intensity, or admixture of noise in a given tone. The sound must last long enough for patterns of change to be established. (i.e. vibrato, speech inflection)
• Timbre: The characteristic tone quality of a sound as determined by the presence and relative strength of its component partials. It depends on the relative strengths of the components of different frequencies, which are determined by resonance. (highly subjective)
• What are the three essential parts of a musical instrument? What is the function of each?(25)
• Actuator: provides the energy/power needed to set the vibrato in motion. 
• Vibrator(s): generates a series of sound waves.
• Resonator(s): influence the intensity and/or timbre of the sound waves. 
• What are the four physical processes required for producing vocal sound? (27)
• respiration, phonation, resonation, and articulation
• Define vowel. (29)
• An unrestricted speech sound that is capable of being sustained, is normally voiced/phonated sound (but can be whispered), is the basic building material of vocal tone, and has a definite shape or form. 
• Define consonant. (30)
• They’re more restricted speech sounds, contain more or less conspicuous noise elements due to restriction, are subordinate to vowels in sonority, form the borders of syllables, and function as sound interrupters, separating vocal tone into recognizable units that can communicate meaning. 
• What are the three main reasons that describing vocal sound is problematic?
• The singer relies a lot on sensation, and it is difficult to describing these subjective muscles senses in a way that is duplicatable. 
• Vocal terminology is taught differently depending on the teacher, so even though people may use the same words to describe a tone, they could have different meanings to different people.
• There are mechanistic and psychological factors that help a singer produce musical sound, and the ratio of employment between the two is entire dependent on the individual; some may utilize one method more than another, and whether or not mechanistic or psychological methods are more helpful changes from person to person.