Digital arts final

Digital Arts Acoustics Study Guide- 

Pitch: The measurement of pitch is cents, and frequency is measured in Hertz. 

Pitch is the quality of sound depending on the rate of vibrations producing it. To create an octave you double the Hertz (you have A4 which is  440 Hz and to get an octave (A5 is double it 880). 

Range of Human Hearing- is 20 Hz to 20,000 Hz (20hz to 20khz)

Cent- 100 cents per half step. This matters because the measurement of cents always sounds the same. Frequency (which is measured in Hertz) is constantly changing and we hear pitch linearly even though it is growing exponentially. 

Timbre- the uniqueness of sound (how you can tell its a clarinet vs a trumpet)\

  • Fundamental: The main pitch 

  • Overtones: the others pitches that add to the main pitch

A2 (110): main pitch 

  • A3 (220)

  • E3 (330)  These are all the overtones (multiply each 440 by 2, then 3, then 4)

  • A4 (440) 


Overtones- the other pitches that add to the bass pitch

  • Harmonics (1, 2, 3 ,4)

  • Inharmonic (2.5, 3.5)

Resonance: when sound waves bounce and sustain. 

Formant: Vowel sounds when you sing a pitch and move your mouth and it changes the overtones but not the main pitch

Amplitude: The specific measurement of how loud something is (objective) (120db is the loudest the human ear can hear). 

dB SPL: decibel sound pressure level (the way to measure the pressure of the sound).

Fletcher-Munson Equal-Loudness curve:our ears are most sensitive/able to hear in the 3-5k area. Super low and very high sounds need to be turned to a higher volume. 

Envelope: the change in something overtime (Violin: sneaks in on attack, sustains, and dies slowly on the release)

Phase: the relationship of sound waves from two or more sources 

Intonation: higher pitches have faster waves so are harder to tune (because you double the hz each octave) Lower pitches are easier to tune because the waves are slower. 

Doppler Effect: if something is moving toward you the closer the vehicle gets the closer the sound waves are so the higher in pitch it is. 


Microphone Vocabulary:

Transducer: something that converts one form of energy to another

Diaphragm: a thin membrane that catches sound waves vibrating that amplifies the sound. 

Pickup Pattern: where the microphone is sensitive 

  • Omnidirectional: picks up sound everywhere

  • Cardioid (unidirectional): one picks up from one area (handheld mic)

  • Supercardioid: sound from the entire top and a little bit of the bottom

  • Hypercardioid: top and more of the bottom (than super cardioid)

  • Figure 8: hears like an 8, mic does not pick up sound from the sides. 

Frequency Response: if you yell into the mic, it will sound like you yelled into the mic. (what you put in is what you get out)

Proximity Effect (near vs. far): if the mic is farther away you will get more room sound rather than if it is closer to you, you will get more of your voice. 

Off-axis coloration: talking into the side of the microphone makes the balance and frequency change the more you tip the mic away. 

  • On-axis: you talk directly into the mic. 

Gain Staging: if you have several places you can turn up & down you want to set them approx the same (if not you will get a more muffled/distorted sound). 

XLR Cables: cables used to hook up a microphone that has 3 conductors. 

  1. Ground (return of electricity-prongs)

  2. Signal 

  3. Single phase flipped

3 types of mics used for recording music: Ribbon, Dynamic, Condenser

Microphones: 

  1. Carbon- used in telephones

  • Needs to be powered

  • High sensitivity 

  • High distortion

  • Poor frequency response (will not pick up super lower or high sounds)

  1. Crystal/Ceramic: Used in CD radios

  • Makes its own power current

  • Fairly low sensitivity 

  • High distortion 

  • Poor frequency response 

  1. Dynamic: used for live music and studio

  • Creates its own power current

  • Medium-high sensitivity 

  • Low distortion

  • Good frequency response

  1. Ribbon: Expensive studio mic

  • Creates its own power current

  • High sensitivity

  • Low distortion 

  • Best frequency response

  1. Condenser: more studio music

  • Phantom power

  • High high sensitivity 

  • Low distortion 

  • Best frequency response

Ideally we want: high sensitivity, low distortion, and best frequency response



Analog VS Digital: 

  • Analog: continuous waves, Uses tapes and manual equipment to record sound on physical media

  • Digital: Samples not continuous, Uses computer software to record/mix

Nyquist Theorem: a signal must have a minimum of 2 samples per wave (dots per wave) Wednesday

Digital Aliasing: too high of frequencies in a signal which makes an outer space kind of sound. When you reduce the sample rate, it reduces the highest pitches (anti-aliasing filter). 

Bit Depth/Bit Depth Quantization: How accurate is each sample (think of a ruler)

  • Lower Bit Depth= fizzy noise & less high sounds

  • Higher Bit Depth= more dynamic range, better recording quality, less noise

Clipping: amplitude (loudness) of recorded sound is exceeding the capacity of the system. (too loud)

Digital Clipping:adds odd numbers of overtones (times 3, 5, 7) and that sounds crunchy/gross. Makes the sine wave blocky because it cuts off the too loud stuff. 

  • Avoid clipping= gain staging (knobs are turned to the same levels)

Digital File Formats:

  • WAV:  windows computers

  • AIFF: Apple computers

                    - Now Interchangeable Mac/PC & Lossless: all data is there 

      -MP3: Digital audio- file gets compressed and some data is thrown out (Lossy: some data is discarded)

                    -Do not repeatedly open + re-export MP3’s. 1 generation of quality lost each time. 

DAW: stands for Digital Audio Workstation and is computer software that can record and edit audio (audacity) or MIDI data. 

What does MIDI stand for: Musical Instrument Digital Interface 

Uses for MIDI: synzesithers 

MIDI Sequenzer: records, edits, and plays back music using digital performance data, not audio. 

MIDI quantization:  a technique that corrects notes that are out of time with a track's rhythmic grid. 

Insert FX: goes directly through the channel (distortion) 

Send FX: “send it out to sea” (Reverb/Delay)

EQ: stands for equalization and boosts or cuts frequency ranges



Pre-fader: is what the singer can hear in their monitor. No matter what you change in the singers monitor is does not effect what the audience will hear. 

Post-fader: what the audience hears. Can change reverb/ delay (effects) to make better overall sound for audience. 

PAD: for overly loud signals 

Oscillator: what makes the sound in a synthesizer. The sound source. 

  • Wave shapes-

  • Sine: no overtones
    Triangle: odd overtones but not strong so the overtones are not loud

  • Square: odd overtones, stronger so overtones are louder. Pulse-width modulation (changes overtones)

  • sawtooth: odd and even overtones