fndn digi music midterm

What is sound, how does it travel, and what are compression and rarefaction?

Sound is vibration traveling as a wave through a medium (solid, liquid, or gas). In air, it is a longitudinal wave made of compressions (high pressure) and rarefactions (low pressure). Sound cannot travel through a vacuum.

What are frequency, amplitude, period, wavelength, and phase?

Frequency = cycles per second (Hz); amplitude = wave size/sound pressure; period = time for one cycle; wavelength = distance between matching points on consecutive waves; phase = a wave's position in its cycle relative to another wave.

How are frequency, period, wavelength, and pitch related?

Frequency = 1 ÷ period. Higher frequency generally means higher pitch and shorter wavelength in the same medium; lower frequency means lower pitch and longer wavelength.

What is the human hearing range, and what are common frequency units?

Approximately 20 Hz–20 kHz. One hertz (Hz) is one cycle per second; 1 kHz = 1,000 Hz.

What is the difference between amplitude and loudness, and frequency and pitch?

Amplitude and frequency are physical properties; loudness and pitch are how listeners perceive sound. Greater amplitude generally sounds louder, and greater frequency generally sounds higher in pitch.

What is phase interference?

When waves are in phase, their peaks and valleys line up and reinforce each other (constructive interference). When out of phase, they can reduce or cancel each other (destructive interference); equal waves 180° apart can theoretically cancel completely.

How fast does sound travel through air, water, and steel?

Approximately 343 m/s in air, 1,481 m/s in water, and 5,120 m/s in steel. Sound generally travels faster in solids than liquids and faster in liquids than gases.

What are reflection, refraction, diffraction, absorption, resonance, and standing waves?

Reflection = sound bouncing off a surface; refraction = sound changing direction as its speed changes; diffraction = sound bending/spreading around obstacles; absorption = a material taking in sound energy; resonance = a strong response near a natural frequency; standing waves = stationary patterns created by interfering waves.

What are sound intensity, SPL, and decibels?

Intensity is sound power per unit area (W/m²); sound pressure level (SPL) expresses sound pressure relative to a reference; decibels (dB) measure levels logarithmically.

What does a 10 dB increase mean, and what are some approximate sound levels?

A 10 dB increase means 10 times the sound intensity and about 3.16 times the sound pressure. Approximate levels: hearing threshold 0 dB, rustling leaves 20 dB, quiet restaurant 50 dB, traffic 70 dB, vacuum 80 dB, pain threshold around 120 dB, jet takeoff around 140 dB.

How does hearing work, and what is the cochlea?

Sound vibrates the eardrum; vibrations pass through the middle ear to the inner ear. The cochlea converts mechanical vibrations into neural signals interpreted by the auditory system.

What are ADC, DAC, and digital audio?

Digital audio represents sound as numerical samples/binary data. An ADC converts analog sound signals into digital samples; a DAC converts digital audio back into an analog signal for playback.

What are sampling rate, bit depth, and audio fidelity?

Sampling rate = samples per second and determines the highest representable frequency; bit depth = bits per sample and affects amplitude resolution, noise, and dynamic range; fidelity = how accurately a system reproduces the original sound.

What are common sampling rates and bit depths?

44.1 kHz and 16-bit are CD standards; 48 kHz is common in professional audio/video; 24-bit is common for recording and production; 96 kHz is a higher sampling rate used in some workflows.

What is the Nyquist theorem, and what is aliasing?

The sampling rate must be greater than twice the highest frequency being represented. The Nyquist frequency is half the sampling rate. Aliasing occurs when frequencies above the usable limit are misrepresented as lower frequencies; anti-aliasing filters help prevent it.

What are quantization error and dither?

Quantization rounds sample amplitudes to available digital levels, creating quantization error. Dither adds low-level noise before bit-depth reduction to make quantization distortion less objectionable and preserve low-level detail.

How do sampling rate and bit depth affect an audio file?

Higher sampling rates allow higher frequencies to be represented and require more data. Higher bit depths provide more amplitude resolution, lower quantization noise, and greater theoretical dynamic range. Neither automatically guarantees better sound.

What are lossy, lossless, and uncompressed audio formats?

Lossy formats discard some information to reduce file size (MP3, AAC); lossless formats compress without losing original data (FLAC, ALAC); uncompressed formats store samples without data-reducing compression (PCM WAV, AIFF).

What are WAV, AIFF, MP3, AAC, FLAC, and ALAC?

WAV and AIFF commonly store uncompressed PCM audio; MP3 and AAC are lossy compressed formats; FLAC and ALAC are lossless compressed formats.

What are bitrate, sample-rate conversion, and bit-depth conversion?

Bitrate is encoded data per second, often in kbps. Sample-rate conversion changes samples per second; bit-depth conversion changes the number of bits used per sample.

What is DSP, and what is the difference between real-time and non-real-time processing?

Digital signal processing (DSP) manipulates digital audio for effects or analysis. Real-time processing occurs during recording/playback and must keep latency low; non-real-time processing is done offline before playback or delivery.

What are normalization, peak normalization, and loudness normalization?

Normalization adjusts gain to a target. Peak normalization targets the highest sample peak; loudness normalization targets perceived loudness, often measured in LUFS. Ordinary normalization changes overall gain, not internal dynamics.

What do EQ, high-pass, low-pass, band-pass, and notch filters do?

EQ adjusts frequency balance. High-pass reduces lows; low-pass reduces highs; band-pass allows a selected range; notch/band-reject reduces a selected range while allowing frequencies outside it to pass.

What are parametric EQ, graphic EQ, shelving EQ, and Q?

Parametric EQ offers adjustable frequency, gain, and bandwidth; graphic EQ uses fixed frequency bands/sliders; shelving EQ boosts/cuts frequencies above or below a point; Q describes bandwidth (higher Q generally means a narrower adjustment).

What is resonance in a filter, and what are comb and all-pass filters?

Resonance emphasizes frequencies near a filter's resonant frequency. Comb filtering creates repeated peaks/notches when a signal combines with a delayed version. An all-pass filter ideally changes phase while maintaining a flat magnitude response.

What is reverb, and how do algorithmic and convolution reverb differ?

Reverb simulates reflections in a space. Algorithmic reverb generates reflections mathematically; convolution reverb uses an impulse response representing a real or modeled space/device.

What are common reverb types and what do they sound like?

Room = smaller space; hall/cathedral = large, spacious tails; chamber = reflective chamber character; plate = dense, smooth metallic reverb; spring = ringing, boing-like reverb; gated = abruptly cut-off tail; reverse = swelling backward-like tail; shimmer = pitch-shifted, ethereal tail; early reflections = first reflections from nearby surfaces.

What are delay, echo, slapback, multi-tap, ping-pong, tape, and granular delay?

Delay repeats a sound after a set time; echo is a distinct repeat; slapback is a short prominent repeat; multi-tap has several timed repeats; ping-pong alternates left/right; tape delay emulates tape coloration; granular delay uses tiny audio grains for repeats and textures.

What are chorus, flanger, phaser, doubling, and ADT?

Chorus uses modulated delayed copies to thicken sound; flanger uses very short modulated delay to create moving comb filtering; phaser uses moving phase-shifted filters; doubling layers a second performance/copy; ADT artificially imitates double tracking.

What are compression, limiting, expansion, gating, and transient shaping?

Compression reduces dynamic range above a threshold; limiting strongly controls peaks; expansion increases level differences; a gate reduces/mutes audio below a threshold; transient shaping changes attack and sustain characteristics.

What are threshold, ratio, multiband compression, and dynamic EQ?

Threshold is the level where processing begins; ratio determines how much compression occurs above threshold; multiband compression processes frequency bands separately; dynamic EQ boosts/cuts frequencies according to changing signal conditions.

What are de-essing, ducking, sidechain compression, automation, and normalization used for?

De-essing reduces harsh vocal sibilance; ducking lowers one sound when another is present; sidechain compression uses a separate trigger signal; automation programs parameter changes over time; normalization adjusts overall gain to a target.

What are saturation, overdrive, distortion, fuzz, waveshaping, and wavefolding?

All can add nonlinear harmonics. Saturation often sounds warm/dense; overdrive is moderate amplifier-like distortion; distortion is stronger waveform alteration; fuzz is buzzy/heavy distortion; waveshaping applies a nonlinear transfer function; wavefolding folds waveform peaks back into the signal.

What are bit crushing, sample-rate reduction, clipping, rectification, and ring modulation?

Bit crushing reduces amplitude resolution; sample-rate reduction creates lo-fi/aliasing artifacts; clipping cuts off peaks; rectification flips or removes waveform polarity regions; ring modulation multiplies signals to create sum and difference frequencies.

What are pitch shifting, pitch correction, formant shifting, harmonization, octave shifting, frequency shifting, and Doppler shifting?

Pitch shifting changes pitch; pitch correction adjusts notes toward intended pitches; formant shifting changes vocal-resonance character; harmonization adds related pitches; octave shifting moves pitch by octaves; frequency shifting moves components by a fixed frequency amount; Doppler shifting is a motion-related frequency change.

What is a vocoder, talkbox, and voice morphing?

A vocoder uses one signal's spectral characteristics to control another sound; a talkbox routes sound through a tube into the performer's mouth to shape it; voice morphing transforms vocal characteristics toward another voice or sound.

What are time stretching, time compression, elastic audio, beat slicing, tempo sync, reverse, stutter, looping, and freeze?

Time stretching lengthens audio while trying to preserve pitch; time compression shortens it; elastic audio changes timing/tempo; beat slicing divides audio into rhythmic pieces; tempo sync follows the beat grid; reverse plays audio backward; stutter rapidly repeats a fragment; looping repeats a section; freeze sustains a moment or texture.

What are LFO modulation, AM, FM, tremolo, vibrato, auto-pan, and filter modulation?

An LFO is a low-frequency oscillator that modulates a parameter. AM changes amplitude; FM changes frequency; tremolo changes volume; vibrato changes pitch; auto-pan moves sound left/right; filter modulation changes a filter parameter over time.

What are FFT, spectral processing, spectral freezing, spectral delay, spectral morphing, and spectral denoising?

FFT (Fast Fourier Transform) efficiently analyzes frequency components. Spectral processing changes a sound's spectrum; freezing sustains a spectral snapshot; spectral delay delays frequency components differently; morphing transforms one spectrum toward another; denoising reduces unwanted spectral noise.

What are granular synthesis, grain clouds, grain density, grain position, grain duration, and granular spatialization?

Granular processing manipulates tiny audio fragments called grains. Granular synthesis builds sound from grains; grain clouds combine many grains; density controls grains per time; position selects source locations; duration controls grain length; spatialization places grains in stereo/3D space.

What are spectral interpolation, cross-synthesis, blurring, smearing, resynthesis, partial extraction, and harmonic/percussive separation?

Interpolation creates intermediate spectra; cross-synthesis combines characteristics of two sounds; blurring smooths spectral detail; smearing spreads energy across time/frequency; resynthesis rebuilds sound from analysis; partial extraction isolates components; harmonic/percussive separation splits sustained tonal content from transients.

What are noise reduction, hiss reduction, hum removal, de-clicking, de-crackling, de-clipping, de-reverberation, de-rumbling, and spectral repair?

Restoration processes that reduce background noise, hiss, electrical hum, clicks, crackles, clipping distortion, room reverb, low-frequency rumble, or localized spectral problems.

What are plosive removal, wind-noise reduction, mouth-noise removal, background suppression, and dialogue enhancement?

They reduce vocal plosives (“p”/“b” bursts), wind noise, mouth clicks/smacks, unwanted ambient sound, or improve speech intelligibility.

What are panning, stereo balance, Mid/Side, stereo widening, Haas effect, polarity inversion, and phase alignment?

Panning places sound left/right; balance adjusts channel levels; Mid/Side processes center-like content separately from stereo differences; widening increases perceived width; the Haas effect uses short delays to influence localization/width; polarity inversion flips waveform sign; phase alignment adjusts timing/phase relationships.

What are binaural audio, HRTF, 3D spatialization, Ambisonics, surround sound, and object-based audio?

Binaural processing aims for 3D headphone localization; HRTF models filtering by the head/ears/body; 3D spatialization places sound in space; Ambisonics represents a 3D sound field; 5.1 and 7.1 are surround formats; object-based audio positions individual sound objects using metadata (e.g., Dolby Atmos).

What are additive, subtractive, FM, AM, wavetable, physical modeling, modal, sampling, and spectral synthesis?

Additive combines partials; subtractive filters a rich source; FM modulates oscillator frequency; AM modulates amplitude; wavetable reads stored waveforms; physical modeling simulates a physical source; modal synthesis combines resonant modes; sampling uses recordings; spectral synthesis creates/rebuilds sound from spectral components.

What are convolution synthesis, cross-convolution, impulse-response modeling, and resonance transfer?

Convolution combines signals to apply system/space characteristics; cross-convolution combines impulse responses/signals; impulse-response modeling describes a system's response; resonance transfer applies resonant characteristics from one source/system to another.

What are stutter, beat repeat, buffer manipulation, tape stop/start, vinyl stop, dropout, glitch, reverse gating, and scrubbing?

Creative/glitch techniques that repeat or rearrange fragments, manipulate buffers, imitate tape/vinyl slowing or stopping, interrupt digital audio, create abrupt reverse-like swells, or move through audio manually.

What are vocal doubling, formant correction, telephone/megaphone filtering, radio simulation, whisper processing, speech synthesis, and dialogue enhancement?

Vocal doubling thickens a voice; formant correction preserves vocal character during pitch shifts; telephone/megaphone and radio effects imitate restricted bandwidth; whisper processing creates whispered textures; speech synthesis generates speech; dialogue enhancement improves intelligibility.

What are the main mastering processes?

EQ, broadband/multiband compression, limiting, clipping, saturation, stereo enhancement, Mid/Side processing, dynamic EQ, loudness normalization, true-peak limiting, dithering/noise shaping, sample-rate conversion, and bit-depth conversion.

What are broadband compression, true-peak limiting, and noise shaping?

Broadband compression affects the full frequency range; true-peak limiting controls estimated peaks between samples as well as sample peaks; noise shaping changes the frequency distribution of quantization noise, often during bit-depth reduction.

What should you emphasize to make a deep, rumbling explosion effect?

Low frequencies, approximately 20–200 Hz.

What effect can help make a sound seem distant?

Reverb, often combined with reduced high frequencies and a lower direct-sound level.

What is the main purpose of EQ in sound design?

To adjust specific frequency ranges to shape tone, remove unwanted content, and help sounds fit together.

What is the difference between a 5.1 and 7.1 surround setup?

5.1 uses five main channels plus a low-frequency-effects channel; 7.1 uses seven main channels plus a low-frequency-effects channel.

What is the difference between real-time and offline effects processing?

Real-time processing must finish quickly enough for live playback; offline processing can take longer and render the result before it is played.