The point of this assignment is to familiarize yourself with both the Audacity audio editor, and with what complex acoustically-generated sounds are like if you look at and listen to them closely. Audacity is already on all of the computers in the Music Library; you can also download it from http://audacity.sourceforge.net/, and it's well worth having it on your own computer.
Use Audacity to play around with these recorded musical instrument samples from the University of Iowa Musical Instrument Samples collection. As a minimum, open and listen to the oboe F4 and A4 (both are monophonic) and the stereo piano A4 (the one that doesn't have "mono" in the filename). Zoom in and out on the screen (click on the magnifying glass to get the zoom-in tool; with the shift key down, it beccomes zoom out). Select and listen to bits of them. Try looping a section of, say, 1/10 sec. of the attack, then 1/10 sec. in the middle (to loop it, just hold down the shift key while clicking play). Then compare the complex real sounds to some simple artificial sounds, as follows.
Open a new file and paste about 0.2 sec. of the oboe F4 into it. Then, in the Generate menu, add 0.1 sec. of silence; then about 0.2 sec. of the oboe A4; then another 0.1 sec. of silence. Now use the first three commands in the Generate menu -- Silence, Tone, and White Noise -- to insert after 0.2 sec. each of sine, square, and sawtooth wave A4's and 0.2 sec. of white noise, following each sound with 0.1 sec. of silence. To roughly match the loudness of the oboe, set the amplitude of each generated sound to about 0.12. Or you can use Effect > Amplify after generating them to reduce their amplitudes (try -20 dB). Each pair of sounds should be separated by 0.1 sec. of silence, so the final sound is 1.7 sec. long, with this structure:
[0.2s: oboe F4] [0.1s: silence] [0.2s: oboe A4] [0.1s: silence] [0.2s: sine A4] [0.1s: silence] [0.2s: square A4] [0.1s: silence] [0.2s: sawtooth A4] [0.1s: silence] [0.2s: white noise]Play around with views some more: zoom way in on the waveform till you can see the little oboe cycles, sines, squares, triangles, and, well, noisiness; zoom in even more so you can see the individual samples. Zoom out. When you open a file, the sound is initially shown as a waveform, with a linear vertical scale, indicated by numbers going from -1.0 to 1.0; change it (by clicking on the little filename to the left of the scale) to dB (decibels, a logarithmic scale), then to spectrum. Instead of the original time-domain view, the spectrum is a frequency-domain interpretation of the sound, showing how strong various frequencies are over time. But since those values change constantly with musically-interesting sounds, Audacity shows a series of spectra, one for every 50 millsec. or so of the sound. Technically, this is a a spectrogram. To see a real spectrum, select most of one of the 0.2 sec. "notes" and give the Analyze > Plot Spectrum command. In the Frequency Analysis window that produces, the number to the right of the word "spectrum" is the number of samples used to compute the spectrum; to see more detail, change it to 2048 or 4096. What do you notice about the spectra of the oboe note as compared to those of the sine, square, and sawtooth waves? What's distinctive about the spectrum of the white noise vs. all the others? Write a sentence or two or three about each, being as specific as you can.
Now open VerklaerteNacht30Sec.wav. This is the first 30 sec. of Michel's audio file from Our Chosen Music, converted to mono. (Converting a stereo sound to mono in Audacity is surprisingly difficult, so I did it for you.) The score is http://www.informatics.indiana.edu/donbyrd/Teach/I545Site-Spring08/OurChosenMusic/Salim_SchoenbergVerklarteNacht_I_Pg1.jpg It shows that the piece opens with a series of slow "chords" each consisting of two notes an octave apart, namely D2 and D3. Find the first chord -- it lasts 2 or 3 sec. -- and copy it to a New file. It's very soft, so use Effect > Amplify to boost it by 20 dB. Select about 0.5 sec., and use Effect > Change Pitch to raise the pitch from D to A (that's 7 semitones). Add 0.1 sec. of silence, then 0.2 sec. of the A to your previous file, so you have 2.0 sec. of sound.
Finally, export the final sound as a .wav, and e-mail it to me (it should be about 175-180KK bytes).