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hat is music? Why is one Technology of Music person's music just "noise" to someone else? What are the different ways music is produced? Why do different musical James Flowers instruments malze different sounds? Whether or not a sound is musical can be a subjective judgement. In general, "musical sounds are those which are smooth, regular, pleasant and of definite pitch. Unmusical sounds are rough, irregular, unpleasant, and of no definite pitch" (Wood, 1975, p. 1). However, this distinction is only approximate. But what is sound? Simply put, sound is a vibration. When a violin string vibrates, it makes the front and back wooden plates of the violin vibrate. These plates make the air vibrate. A series of longitudinal pressure waves passes through the air to the ears. The alternating higher and lower pressure of these waves make the eardrums vibrate and sound is heard. F&we 1. Computer screen from Pe@ormeF sojhvare. (Courtesy of Mark of the Unicorn.@) The science of sound is called acoustics. There are many areas and applications of acoustics. Musical acoustics is the science of musical sounds. Architectural acoustics is concerned with the behavior of sound in and around structures. SONAR (Sound NAvigation Ranging) can detect the presence of submarines. Ultrasonics refers to the use of sound waves that are too high pitched for us to hear. Among the many uses of ultrasonics is its ability to produce a picture of a developing fetus. Unlike X-rays, ultrasound does not pose a radiation hazard. Nearly all areas of acoustics involve the same basic areas: sound propagation, sound transmission and sound reception. Music is a form of communication. It begins with the musician (sender) using an instrument (encoder) to produce a series of sounds (coded message). The sounds are transmitted fi-om one place to another through the air (channel). A listener (receiver) uses his or her ear (decoder) to make sense of the sounds. As with other art forms, the decoded message is not necessarily the same message that the musician intended to transmit. This can work to our advantage; the same piece of music can make us feel different each time we hear it. Most musical sounds have three basic characteristics: pitch, loudness and timbre. Pitch refers to how high or low we perceive a note to be. Loudness is our impression of the strength of the sound. Timbre is the "color" of a sound. A bamboo flute and an electric guitar may be able to each play a note of the same pitch and loudness, bet the two notes sound different due to their timbre. There have been recent advances in musical technology. Most of these concern the electronic manipulation of musical information. Historically, musical technology has primarily involved the instruments used to make music. After briefly classifying musical instruments, there will be examination some relatively new musical technologies and a closer look at what sound is. Contemporary Analysis Musical Instruments Musical instruments can be separated into five different classifications (Campbell and Created, 1988): ideophones, Figure 2. S&nal prnduced @om an ADSR unit in a music yntbesizer. Signal amplitude (vertical) is membranophones, chordophones, plotted a~ainsttime (horizontal). Wave 1 is a trianplar carrier wave uith the amplitude envelnpe shoivn aerophones and electrophones. in 2. A = attack time; D = initial decay time; S =sustain level; and R = release time. Ideophones include rattles, xylophones, thumb pianos, jaw harps, gongs and triangles. They all produce sounds without the application of additional tension, unlike drum skins and strings. The materials making up thesc instruments have natural direc~onalshift in air determines the pitch vibrating element, but is not capable of tonal properties. A membranophone we hear. The sound produced is called an adequate acoustic amplification. These produces sound with a skin or membrane. edgetone. Another type of aerophone, instruments rely on electronic amplification. Usually, the membrane is stretched over an which includes oboes, clarinets and A solid-body electric guitar is an example; opening and is struck. Drums produce saxophones, uses flexible cane reeds that without electronic amplification, these sound this way. However, a kazoo is a vibrate at a frequency based on the size of guitars are very quiet. membranophone that works by blowing air the column of air in the instrument. A third type of electrophone relies solely across a membrane. Chordophones, such The fifth classification of musical on electronics to synthetically produce (or as violins, guitars and pianos, use vibrating instrument is the electrophone. synthesize) and amplify sounds. This means strings to produce sounds. However, a Electrophones produce electronically that we can create new, "unnatural" vibrating string is not very loud. In order to amplified sounds. There are three types of sounds. Robert Moog and Donald Buchla increase the volume (amplitude) of the electrophones. The first type relies on an separately developed the first commercial sound, each of these instruments has a acoustic (i.e., non-electronic) production of synthesizers around 1966 (Elsea, 1990). soundboard made out of wood. The the original sound. An acoustic guitar is These synthesizers use voltage-controlled soundboard is carefully manufactured, capable (as a chordophone) of producing oscillators, amplifiers and filters to produce usually out of a piece of spruce that has very sounds independently of electronic sound. Greater control over the sounds is straight grain. Special attention is given to amplification. However, by putting a small made possible with an ADSR envelope the thickness of the soundboard and the transducer or a microphone on an acoustic generator. This allows a musician to placement of braces. Braces stiffen certain customize the attack time (A), the initial areas of a soundboard; they divide a guitar, we can change the guitar into an soundboard into smaller sections. Each of acoustic-electric guitar. Preamps can be decay time (D), the sustain level (S) and the these smaller sections is of a proper size to used to modify the signals from these release time (R) (see Figure 2). resonate when a certain tone is produced. transducers before they reach an electronic The different areas of a soundboard amplifier. Some of these preamps are small Advances in Acoustic Musical respond diikrently depending on the enough for bass players and guitarists to clip Technology Throughout our history, frequency of a string's vibrations. onto their belts. Typically, they allow a people have been inventing and changing Aerophones produce sound with a musician to make rough adjustments to the musical instruments. Ovation Guitars vibrating column of air. A flute produces a different frequency ranges (bass, midrange produced the Roundback, a guitar with a very clear sound. One type of aerophone, and treble). The signal from these molded plastic body. However, certain which includes flutes and whistles, produces transducers can also be mixed with a instruments reached a plateau in their very clear sounds directing a continuous microphone's signal. The user can evolution many years ago. The violin, for stream of air against a sharp edge, splitting separately adjust gain, bass, treble and phase example, has not changed significantly in the stream of air. If the angle and air control for the separate signals and for the hundreds of years. In fact, many luthiers velocity are just right, the air will tend to go mixed signal. (i.e., stringed instrument makers) today try first to one side, then to another, in a A second type of electrophone is an as best they can to copy very old violins, rhythmic fashion. The kequency of this instrument that produces sound with a such as those made by Stradivari. But this does not mean that musical technology has Advances in Electronic Musical must be aware of the abilities of all their stood still for those instruments. Technology equipment in order to produce the desired Technology has bccn used to find out what Hooking together many electronic musical sounds. makes a fine violin sound so pleasing. devices on a stage or in a recording studio Electronically encoded MIDI messages

Researchers have studied wood anatomy in can be very complicated. In the past, if you pass along a cable kom one de\rice ' to relation to violin tone (Bond, 1976), wanted to attach one brand of keyboard to another. There are sixteen independent acoustical effects of violin varnish another manufacturer's controller and a channels in that cable. If the sender and (Schelleng, 1968) and the tuning of violin third manufacturer's speaker system, you receiver are on the same channel, they can plates. were often out of luck. Different communicate. Cables that connect MIDI manufacturers had different configurations Joseph Nagyvary (1988) examined the devices plug into three different types of on their products-some devices just could wood in old violins. He found that the MIDI ports: In, Out and Thru. All three not communicate with other devices. To wood in some eighteenth century violins ports accept a round, 5-pin jack, but they overcome this problem, a protocol or made by Antonio Stradivari and other serve different functions. An "In" port standard was developed in the early 1980's. master luthiers contained two items not It is the Musical Instrument Digital allows a device to receive MIDl normally found in present day instruments: Interface, abbreviated MIDI (O'Donnell, information. After processing, information high salt concentrations and evidence of 1991 ). Now, devices that use MIDI can is output through the "Out" port. The microbes. No doubt, the logs used to make communicate with one another. third type of port, "Thru," outputs a these old violins were transported or stored MIDI is not audio information. It is a duplicate of the information coming into in salt water. Unlike some other wood specified language regarding musical the "In" port. MIDI signals can only travel hngi, sapstain hngus does not feed on the performance. Different performance in one direction in a MIDl cable. They cell walls in wood; it lives off the contents gestures, not actual sounds, are either travel from an "Out" to an "In" or of living wood cell cavities. However, by electronically communicated. For example, from a "Thru" to an "In." growing from one cell to the next, sapstain an output device might be instructed how A sampler is an electronic input device tends to increase the porosity of wood. and when to play a specified note or to similar to a tape recorder. It allows the user Wood that is more porous will tend to change that note in a certain way. There are to digitally record sounds. The sounds are absorb more finish at a greater depth than also instructions to change the program and captured and converted to binary electronic less porous wood. Since his discovery, select a new type of sound. The final output information using an analog-to-digital Nagyvary has experimented with is limited by the ability of the devices to converter (ADC) (Burger, 1991). A microbially modified spruce and different carry out MIDI instructions. Switching to a musician can then store this information violin varnishes containing glass to produce specified sound on a master keyboard may (usually on a hard disc drive), edit and high-quality modern instruments. not cause the output device to play that retrieve the digitized samples. Finally, the Nagyary, and others, are continuing to same sound. "If program 23 on the master edited binary signals are sent to an output advance acoustic musical technology, controller is selected, the receiving device device called a digital-to-analog converter however, many of the latest breakthroughs will call up its own patch 23, without (DAC). "A sampling rate of 44.1 kHz is have come in the area of electronic musical regard for the nature of that sound" normally required for professional results, technology. (O'Donnell, 1991, p. 78). MIDI operators due to the hll frequency response it yields" (Burger, 1991, p. 60). F&re 3. MawTracks Pr@ tc a MIDI sequencer program forpersonal computers. (Courteg of Passport nest&, Inc.@) The sampler is connected to a source of sound, such as a CD, tape deck, mixer or microphone. Nearly any type of sound can be sampled: a dog's bark, the sound of a jet taking off, a doorbell, a heartbeat. Many sound samplers are equipped with their own library of sounds. After recording (or sampling) the sound, it can be assigned to a pad or key on a keyboard. The sound can be looped or repeated just by pressing that key. A sequencer is an input and processing device. It is similar to multitrack tape in that it allows a musician to record on separate tracks. It is also similar to a player piano roll, because a sequencer does not record any sound; instead it records which notes were played, when they were played, how long they were held, etc. (Phillips, 1991 ). Guitars and electronic drum systems are also used for input of MIDI information. The drum system in Figure 4 is compact and lightweight. With a built-in sequencer, the drummer has much more control over Figure4, Drum the personal computer one step further, we sYnem,@photo courtesy of can incorporate movies, animation, ~~l~~dcovpovatjonUS,") graphics, sound and music into a single master control file (see Figure 7). Social/Cultural Impacts What will be the impacts of the increasing sophistication of electronic music technology? What are some predictions for the hture of music technology? Musical electronics have been rapidly advancing, but the interface through which humans control and manipulate the technology has not kept pace. Tiny buttons, poor display screens, complex keystroke commands and poorly responsive keyboards have led Robert Moog (1990), developer of some of the first music synthesizers, to conclude: Now we have to go through a period of matching the capabilities ofdigital instruments to those of the human musician. We'll have to go back to old- timey mechanical manufacturing technology to come up with finely tuned performance controllers and specialized data entry surfaces that are ergonomically optimized. (p. 37) One trend in musical technology is a the performance. Using headphones, you best sound blend. Mixers offer separate greater reliance on computers for the can even practice without waking up the controls for gain, fading, location, etc., for manipulation of musical information. As neighbors. each of the tracks to be blended. Mixing is with other computer applications, after In one sampler/sequencer by Roland an art; it requires sensitivity, creativity and hardware is developed, software continues (see Figure 5), 24 samples can be played patience. to be developed to take better advantage of simultaneously. A disc jockey can stretch or MIDI does not require a personal the hardware's capabilities. This often compress samples without changing the computer. However, by linking a computer results in a time lag between the pitch. Samples can be monitored on with a MIDl interface to a MIDr system, a introduction of new hardware and the headphones without interrupting the musician can have much greater control introduction of the software that takes best music. Because of their format, samples can over the music produced. A personal advantage of that hardware. Within a be saved to disk. You can even make a computer can now not only take the place relatively short time, the hardware may be record of every pad and key that the DJ of a mixing studio, it can replace an entire replaced by newer, more advanced presses and assign this timed series of orchestra of instruments. Taking MIDl and Continued on paHe 23 keystrokes to a single key. This allows very complex mixes to be performed with just a few keystrokes. FigMrc 5. Roland 01-70 Sampling Worknation.@(Photo courtey of Roland Co~porationUS.@) Once a sound is sampled, a sound editor allows the user to edit the sound. It can be elongated or shrunk to fit a precise time slot. Resides editing a sampled sound, some software packages, such as Passport's Alchemy (see Figure 6), allow a musician to design completely new sounds '%om scratch." The waves of these sounds can be precisely altered to the user's satisfaction. Whether sounds are sampled or created by a computer, they can be edited and blended in a professional sound designer and editor. Since most of the music we hear is mono or stereo, it is common for all the separate tracks to be mixed into just one (for mono) or two (tbr stereo). Whether or not MIDI is involved, recording technicians use mixers to create their impressions of the RIT I 6 File Edit Process Network Windows Rction I Continuedfi-om pafie 12 hardware. Because of the relatively short life of "state of the art" computer hardware, some systems never reach their hll potential; before the software can be hlly developed, a new "state of the art" hardware system is introduced. Consumers, therefore, have tended to be overly conscious of advances in computer hardware. Hartley Peavey (l990), president of Peavey Electronics, predicts a change in this trend: We are approaching the end of the "hardware era" and rapidly approaching the "sohvare era" of electronic music. More and more electronic music equipment is becoming sohare-driven to allow for sounds, features, and thctions not included in the original systeni. (p. 40) 0. J.I$~I~~Yc. Raymond Kurzacil ( 1990)' of Kurzweil F&MW Screen shot nfAlchem?@sound desgn and editin'q (Cuurtc? ofPasspovt Designs, 1nc.B) Music Systems, predicts that "music will move bit by bit away from passive entertainment toward an active, learning experience" (p. 30). He envisions a participatory listener of music; the musical composition will change based on signals f?om the listener, which mav be as involuntary as "subtlc facial expressions, muscular tension, perhaps even brainwaves" (p. 30). Bccause of recent advances in musical technology, it is now possible for a singlc musician, working alone, to play music that would have previously required a number of musicians and many different instruments. This independence may result in more isolation and less social/musical interaction with other musicians. David Kusek ( 1990), thc president of Passport Designs, offers a personal comment: "If people in large numbers begin to produce music all alone or use the technology to replace the stimulating environment of a group of musicians, I think that will be a sad day Despite the unlimited potential otyered by these instruments, I hope manu6cturers can develop products that help avoid David Schaartz ( 1990), editor-in-chief' particles tends to repeat in regular cycles. electronic musicians' propensity to play and co-founder of Mix Magazine, is The duration of time from one cycle to the alone. (p. 34)" amazcd at the rate of technological next is called the period ofthe vibration. Jerry Harrison ( 1990), keyboard player development in electronic music. However, Waves in the ocean have a period also. You for the Talking Heads and band leader for he states that our present "tool building can calculate their period by measuring the Causal Gods, notes that there has been a outpaced our creative musical development. time between successive wave peaks at any tendency for users of electronic musical Perhaps when we catch up, we'll see a new one place. instruments "to become librarians, rather Renaissance in music making" (p. 46). than creators of sound" (p. 43). He Figure 8 is a graph for a periodic predicts a change in the future as musicians Technology/Math/Science Interface compression wave. The center horizontal rediscover their power to shape their own Most musical sound waves are periodic. line represents ambient air pressure. Above sounds. This means that the motion of vibrating that line, the air pressure is temporarily greater. Points b,f; and j are all located at the crests of waves. The vertical distance between the centerline and these points of

greatest compression determines the + PERIOD 4 amplitude of the wave. Points d and h I represent the lowest pressure; low pressure areas are called rarefactions. The wave begins at point a. Air pressure builds to a maximum at point b. As the pressure then drops, it passes its original level at c and reaches a minimum at d. Upon returning to its original level at e, the wave has completed one hll period. The frequency at which a compression wave's vibrations occur determines, for the most part, the pitch of a sound. Pitch is our perception of how high a tone is. I Frequency (f) is usually measured in cycles per second (cps) or Hertz (Hz); it is a TIME - measure of how kequently waves arrive. One kiloHertz ( 1 kHz) is equal to one thousand Hertz. A piano with 88 keys can produce notes with frequencies from about Fgure 8. Representation of'a sound wave based on a sine curve. 26 Hz to about 4200 Hz. The period is the reciprocal of the frequency: T = 1/ f [alternative form: f = 1 / T where: The Speed of Sound in Various Materials f = frequency (in Hertz or cycles per second) T = period (seconds) Material Speed of Sound For example, what is the period of an EJ note with a fi-equency of 78 Hz? Air Solution T=I /f Sea Water T=1 /78Hz T = 0.0128 sec. Wood Sound travels different speeds in different materials (see Table 1). Fortunately, air is a "non-dispersive" medium for sound waves. Steel That means that sound waves of different frequencies tend to stay together. Gypsum Board The speed of sound in air at a temperature of 20°C is approximately 344 meters per second (mps), or 1130 feet per Source: Everest, 1989, p.61. second or 770 miles per hour. In general, the speed of sound in air increases about L 0.6 mps for every 1°C temperature increase Table 1 (Hall, 1980). At 30°C, the speed of sound The Speed of Sound in Various Materials in air is about 350 mps. The speed of sound, like the speed of anything else, can be calculated by dividing the distance a new composite material if a sound wave the delay between a flash of lightning and traveled by the time: moves 20 meters in 0.01 seconds? the report or sound wave, you can divide c = d / t [alternative forms: 6 = d / c; your count by 3 to roughly determine the d = ct] Solution distance to the lightning strike in where: c=d/t kilometers. c = speed of sound (in meters per c = 20 m / 0.01 sec The wavelength (A) of a sound is the second) c = 2000 mps linear distance between consecutive waves. d = distance the sound travels in a given Since 344 meters is slightly more than It can be computed based on the speed of time period (in meters) one-third of a lulometer, we can say that sound and the ti-equency of the sound. t = time period (in seconds) sound travels one kilometer in about 3 A = c / f [alternative forms: c = tX; For example, what is the speed of sound in seconds in air. By counting the seconds in f=c/A] where: ruler to make sounds. She holds one end of biggest change of late has been in electronic A= wavelength (in meters) the ruler down against her desk. The other musical instruments. Synthesizers allow a c= speed of sound (in meters per second) end hangs ofrthe edge of the desk. When musician to customize a sound, otten by f= frequency (in Hertz or cycles per second) she thumps the overhanging edge, a tone is changing the ADSR envelope. MIDI was For example, at a temperature of 20°C, a produced. She has a code sheet that assigns developed to improve communication trumpet plays a note with a frequency of different numbers to gestures such as: between electronic music devices; MIDI 220 cps. What is the wavelength of the thump softly, thump hard, dampen, slide devices input, process and output codes note? ruler toward edge, slide ruler away kom regarding performance gestures. edge. The purpose of most musical Solution technologies is to create music. Music is a A=c/f Challenge form of communication that uses sound. A = 344 mps/220 cps Using only the materials specified, design Sound is a longitudinal wave of pressure. If A = 1.564 m and construct an original musical the wave is periodic with a frequency Although the ability to hear is difrerent in instrument capable of producing sounds of between 20 Hz and 20 kHz, we can hear a different people, in general, humans can different kequencies. Make a list of distinct pitch caused by that fi-cquency. hear sounds with kequencies as low as 20 different performance actions/commands Loudness and timber are two other Hz and as high as 20 kHz (Hall, 1980). possible on your instrument, assigning a characteristics of musical sound. Sound Below 20 Hz, we can still feel vibrations, name and number for each (starting with travels about 344 mps in 20°C air, but its but they do nit seem to have any sound: If the number 1). speed varies directly with air temperature. you blow a high-pitched dog whistle, it The speed of sound is different when it does not seem to make any sound, but your TieLimit: 20 minutes. travels through different materials. dog can hear it. This is because dogs can As musical technology advances, we hear higher pitched sounds than humans Objectives should keep it in perspective. It is a tool can hear. 1. Demonstrate creative problem-solving that allows us great control over the sounds Pitch is only one of three properties that skills. produced, but are the sounds we produce characterize a tone. The other two 2. Investigate musical technology. expressive and beautiful? We should properties are loudness and timber. The 3. Experiment with sound production. overcome the urge to become slaves to the loudness of a sound is determined by rate at 4. Develop a coding system for musical new musical technologies (i.e., hardware which vibrating particles impart energy to performance. and sofhvare "junkies.") Instead, we should our eardrums. In general, loudness use musical technologies, old and new, to increases as the amplitude of the pressure Materials broaden and enhance our expressiveness. wave increases, but loudness is also affected Empty aluminum cans, balloons, empty by the wave's frequency and shape bottles, paper, waxed paper, rubber bands, Possible Student Outcomes (Campbell and Greated, 1988). Timbre string, water, nails, and strips of pine 1. Analyze the components of musical refers to the tone color, that is, the measuring 1/4" X %" X 15. sound. character of tone produced by a certain 2. Classifp musical instruments and method. A violin, flute and electric guitar Evaluation (includes feedback) describe their production of sound. can all play the same note at the same 1. You will have 30 seconds to present 3. identify recent advances in musical volume. However, the tones from the three your instruments to the class. Your technology. instruments will sound different. Analysis of presentation will include the instrument's 4. Describe the impacts of musical the sound waves reveals that all three have design and construction. You are to briefly technology on society. roughly the same frequency, period and play a few sounds on your instrument for amplitude. It is the roughness and the class. Afterwards, there may be a brief irregularities in the waves, evident in Figure class discussion or questions. Student Quiz 6, that are different. 2. All musicians will assemble with their 1. What are acoustics? instruments and perbrmance code sheets. 2. Describe music in terms of a The instructor will "conduct" the communications model. Design Brief musicians by holding up cards with number 3. List five difrerent families of musical on each card. When a number is held up, instruments. Designing and Coding a Musical comply with the corresponding 4. What is the approximate speed of Instrument performance gesture on your code sheet. sound in 10°C air? 3. Your code was developed for your own 5. If you see a flash of lightning, and six Context instrument. Write a paragraph explaining seconds later you hear the thunder, about A new band is forming at your school called how the code might be difkrent if you had how many miles away will the lightning "Original Numbers." The musiciaiis in the tried to develop it for all the instruments in strike? band play their instruments according to the band. 6. What do the letters in MIDI stand for? iiumerically coded commands. To join the 7. What does a sequencer do? group, you must have two things. First, you summary 8. Give an example of recent research into must have an original musical instrument Musical instruments can be classified as violin technology. that you invented. Second, there must be a either ideophones, membranophones, 9. Describe the major shifts in musical number code corresponding to different chordophones, aerophones or technology in the 20th Century. performance gestures on the instrument. electrophones. While there is still scientific 10. Discuss two impacts of electronic music One of the band members uses a wooden interest in all typcs of instruments, the production on the musician and society. References temperature is not 20°C, then the speed of Bond, C. W. (1976). Wood anatomy in sound will be 0.6 mps higher for every "C Elementary Design relation to violin tone. Journal of the over 20°C, or 0.6 mps lower for every "C Brief-A Variety of Institute of Wood Science, 7(3),22-33. under 20°C. Burger, J. (1991). EM g~tideto samplers. Sounds Electronic Musician, 7(7),59-62. Equipment Context Campbell, M., & Greated, C. (1988). The Large outside masonry wall with about 40 Some musicians try to get a wide variety of musicianspuidc to acoustics. New York: meters of space in fi-ont of it sounds from their instruments. A guitarist Schirmer Books. Thermometer might drum on the guitar. A drummer Elsea, P. (1990). Inventors and iconoclasts. Watch (indicating time in seconds) might tap the drumsticks against the rim of Electronic Musician, 6( 12), 70-73. Tape rule a drum. Everest, F. A. (1989). i'he master handbook of acoustics (3rd ed.). Blue Ridge Challenge Summit, PA: Tab Rooks I11c. Procedure Using only the assigned materials, make as Hall, D. E. ( 1980). Musical acoustics: An Stand 30 to 40 m away fi-om the wall. many ditferent sounds as you can. You will introduction. Belmont, CA: Wadsworth Record the air temperature (temp). Clap have two minutes to experiment with Publishing Co. your hands once and listen for the echo. different sound before a competition begins. Harrison, J. ( 1990). Looking ahead: Now clap your hands at a steady rate where Visions for the 1990's: Jerry Harrison. the echo returns exactly in between two Objectives Electronic Musician, 6( I ), 43. consecutive claps. Using that rate of 1. Demonstrate creative problem-solving Kurzweil, R. ( 1990). Looking ahead: clapping, have a partner time how long it skills. Visions for the 1990's: Raymond takes for 10 claps. Be carehl: if you start 2. Investigate musical technology. ICurzweil. Electronic Musician, 6( 1), 30. timing on clap number 1 you should stop 3. Experiment with sound production. Kusek, D. (1990). Looking ahead: Visions timing on clap number 1 1. Record this for the 1990's: Dave Kusek. Electronic time in seconds as "t , ." Measure and Materials and Equipment Each student will be assigned one of the Musician, 6( 1 ), 34. record the distance to the wall in meters as Moog, R (1990). Looking ahead: Visions "d,." following sets of materials: Set A: 2 sheets of paper for the 1990's: Bob Moog. Electmnic Set B: 2 rubber bands Musician, 4 1 ), 36-37. Data Analysis Set C: 2 blocks of wood (I" X 4" X 12") Nagyvary, J. (1988, May 23). The Every clap sent a sound wave that traveled to the wall and back to your ear. chemistry of a Stradivarius. Chemistq Evaluation (includes feedback) Therefore, the distance traveled by every and En~inecrin~News, pp. 24-3 1 . Mer two minutes of experimentation, sound wave was equal to twice your O'Donnell, B. (1991). What is MIDI, students will stand quietly in rows anyway? Electronic Musician, 7( 1), distance to the wall. Compute d by according to their group. (Group A used 74-79. multiplying dl by 2. the paper, Group B the rubber bands and Peavey, H. D. ( 1990). Looking ahead: In order to find t, remember that the Group C the wood.) Following the Visions for the 1990's: Hartley Peavey. sound wave made the round trip to the wall teacher's directions, the first student in Electronic Musician, 6( I), 38-40. and back in only half the time between two Group A will demonstrate a sound. Next Phillips, D. ( 199 1). How sequencers work. claps. Since there were 10 claps, compute t the first students in Group B and then C Electronic Musician, 7(4), 86-9 1. by dividing t , by 20. dldemonstrate one example each. The Schelleng, J. C. ( 1968). Acoustical etkcts Next determine the speed of sound (c) in teacher will ask the second student in of violin varnish. Journal of the Acoustical mps by using the equation c = d / t. Group A to demonstrate a direrent sound. Societ?,$America, 44, 1 175- 118 1 . Using 344 rnps as the theoretical speed If that student does not make a new sound, Schwartz, D. (1990). Looking ahead: of sound at 20°C, compute the theoretical he or she passes and sits down and the next Visions for the 1990's: David Schwartz. speed of sound (c,,,) at your recorded Group A student gcts a chance. The Electronic Musician, 6(1), 4546. temperature. Remember that for each competition continues until only one student is standing. This student is crowned Wood, A. ( 1975). 'TI.lephysics of music. New degree above 20°C you should add 0.6 mps "Dr. Music" for the day. York: John Wiley & Sons, Inc. to 344 mps, and for each degree below 20°C you should subtract 0.6 mps fi-om 344 mps. Experiment-The Speed of Sound Resources in techno lo^ is written by (The following experiment is based on Tidewater Technolo~yAssociates. Hall, 1980.) Conclusions Walter F. Deal, III, Editor How does the theoretical speed of sound at Purpose Fred Hadley your recorded temperature (c,,,) compare to James A. Jacobs To measure the speed of sound in air and to the value you computed for c? Are the two verify the relationship between speed of John M. Ritz, DTE values as close as you expected considering sound and air temperature. K. George Skena the techniques used? Why is measuring the Dr. James Flowers is Assistant Profissor, Hypothesis time for 10 claps more precise than just Occupational and Technical Studies, Old Sound will travel through air at 344 meters measuring the time between a clap and its Dominion Univ., No@olk, VA. He isaJuest per second (mps) at 20°C. If the air the air echo? author for this article.