Possible Midterm Topics

Computer Audio and Music Programming
Music 147 / CompSci 190 / EECS 195 / ACE 277

University of California, Irvine
Winter Quarter 2007

Possible Midterm Exam Topics

What causes sound?

What does "amplitude" refer to?

What does "frequency" refer to?

What characteristics must sound have for us to hear it?

What is the range of frequencies audible to humans?

How is sound recorded digitally?

What does "sampling rate" refer to?

What is "aliasing"?

What is the physical and audible effect of aliasing?

What is the "Nyquist theorem"?

What is the definition of the "Nyquist frequency"?

What aspect of the recorded (or synthesized) sound is affected by the sampling rate?

What is meant by "quantization precision" or "bit precision" in digital audio?

What aspect of the sound is affected by precision quantization?

What is quantization noise?

How do you calculate the amplitude of quantization noise?

What is the process of operations by which sound is quantized and played back?

What is a "low pass filter"?

Why do we use a low pass filter before digitally recording sound?

Why do we use a low pass filter when playing digital audio (when converting it from digital to analog information)?

What is "simple harmonic motion"?

How is simple harmonic motion related to the trigonometric "sine" function?

What is a "complex" tone?

Are most sounds simple or complex?

What does "spectrum" refer to?

What does "timbre" refer to?

What is "additive synthesis"?

What is "wavetable synthesis"?

What mathematical operation corresponds to the analog phenomenon of "amplification"?

What does "amplitude envelope" refer to?

What does "envelope" in general refer to?

What are the differences in amplitude envelope between a plucked string (such as a guitar), a (gently) blown tube (such as a flute or a trumpet), and a struck surface (such as a xylophone or a drum)?

What is the relationship between "frequency" and "pitch"?

What is an "octave"?

How does one calculate "equal temperament" of the pitches used in most Western classical music (e.g., a piano or a synthesizer keyboard)?

What is the relationship between "amplitude" and "loudness"?

What is a "decibel"?

What does a decibel measurement refer to?

How does one calculate the decibel difference between two amplitudes?

What is "frequency modulation" (FM)?

What is "vibrato"?

How do we create the effect of vibrato by means of frequency modulation?

What is a "low frequency oscillator" (LFO), and why is it useful?

What happens when we increase the amplitude of the modulating wave?

What happens when the frequency of the modulating wave is at an audio rate?

How can we calculate what frequencies might be produced by FM at an audio rate?

What is the "harmonicity index"? How can you calculate it?

What is the "modulation index"? How can you calculate it?

What happens to the timbre of an FM sound as you increase the modulation index?

What kind of tone is produced when you use a non-integer harmonicity index?

What is the difference between Max messages and MSP signals?

Does a control signal generally change faster or slower than the audible signal?

What are some uses of control signals?

What is "sampling"?

How does a sampling synthesizer work?

What MSP objects are particularly useful for sampling?

What is a "sustain loop" in a sampling synthesizer? What is it good for?

How do you create a wavetable in MSP?

What are some things that a computer can do that a human instrumentalist cannot do?

What is "ring modulation"?

What mathematical operation is used to achieve ring modulation?

What frequencies are produced when you ring modulate two sine waves of frequency f1 and f2?

What would happen if you ring modulated two complex tones?

What is "clipping"?

If you play two simultaneous notes at full amplitude in MSP, what will happen?

What will the audible effect probably be?

How would a schematic diagram of a simple frequency modulation instrument look?

Without consulting your notes, can you design an FM instrument in MSP and play a note on it?

Once you have done that, can you describe what the note will sound like, and why?

What does the acronym MIDI stand for?

What is MIDI?

What is the transmission rate of MIDI data?

Is MIDI good for transmitting digital audio?

What are the different types of MIDI "channel messages"?

What is a "status byte"?

What is the distinguishing characteristic of a status byte?

What is a MIDI channel?

Why is a MIDI channel useful?

Where does the MIDI channel information reside in a MIDI channel message?

How many bytes are in a MIDI note-on message?

What information is contained in a MIDI note-on message?

What is the MIDI code number (key number) for the pitch middle C?

What is MIDI note-on "velocity"?

How is velocity generally measured on a keyboard?

What is MIDI "pitchbend"?

What is the difference in transmission and usage between MIDI "events" such as notes, and "continuous control" messages (such as volume)? That is, what is different between the way that a keyboard sends out MIDI note messages and volume messages, and why is that difference musically necessary?