Chapter 14 Quiz

Closed book, synth closed too — this is the vocabulary-and-thinking check; the exercises own your ears and your hands. Multiple choice: 1 point each. True/False: 2 points (1 for the verdict, 1 for the justification — a lucky coin-flip with a wrong reason earns half). Short answer: 3 points each. Applied scenario: 5 points. Total: 42. Scoring table at the end. Wrong answers are a reading map, not a verdict — every miss here is cheaper than the same confusion at 2 a.m. with a patch on the line.

Multiple Choice (15 × 1 pt)

1. The subtractive signal path, in order, is:

  • A) Filter → oscillator → amplifier
  • B) Oscillator → mixer → filter → amplifier
  • C) Amplifier → filter → oscillator → mixer
  • D) Oscillator → LFO → filter → amplifier
Answer **B.** Tone has to exist before anything can shape it: oscillators generate the raw harmonic material, the mixer blends them, the filter carves the harmonics, the amplifier shapes loudness over time. A and C put a sculpting or loudness stage before there's any sound to sculpt. D is the sneaky one: the LFO is a *modulation source* — it floats above the path wiggling parameters; it never sits in the audio path itself.

2. The sawtooth is the default raw material of subtractive synthesis because:

  • A) It contains only odd harmonics, which filters respond to best
  • B) It's the loudest of the basic waveforms
  • C) It contains every harmonic, so the filter has the maximum material to carve
  • D) It uses the least CPU
Answer **C.** Subtractive design happens by removal, so the best starting block is the one with the most to remove — and the saw's recipe is all harmonics, strong. A describes the square (odd harmonics only), and filters have no preferences anyway — they remove whatever's there. B confuses level with content; loudness is the amp's job. D is irrelevant to harmonic content (and false in practice — a plain saw is cheap everywhere).

3. For a sub bass that must read as pure weight and never fight the rest of the mix, you start with:

  • A) A sawtooth, because bass needs harmonics
  • B) A sine, because fundamental-only content gives low-end weight with nothing left over to mask the mix above it
  • C) A square, for hollow body
  • D) Filtered white noise
Answer **B.** The sine is all fundamental — nothing above it to collide with vocals, guitars, or anything else ([Chapter 4](../../part-01-sound-fundamentals/chapter-04-listening/index.md)'s masking logic applied at the source). A puts buzz exactly where the rest of the arrangement lives; the saw is the wave you *plan to filter*, not the one you park in the sub lane raw. C's odd harmonics still climb into the mids. D has no pitch at all — useless for a bass *note*, excellent for hats and risers.

4. "Subtractive" in subtractive synthesis refers to:

  • A) Removing oscillators one by one as the note evolves
  • B) Reducing the patch's level until it fits the mix
  • C) Subtracting the filter envelope from the amp envelope
  • D) Starting with harmonically rich material and removing harmonics with a filter
Answer **D.** It's sculpture: start with more sound than you need, carve away until what remains is the thing you meant. A, B, and C are invented mechanics — oscillators don't retire mid-note, level isn't design, and envelopes don't do arithmetic on each other. The name describes where the design happens: in the removal.

5. You detune two saws apart for a pad and push past roughly twenty cents. What does the chapter say happens?

  • A) The shimmer gets faster but stays musical at any width
  • B) The ear stops hearing "ensemble" and starts hearing "out of tune" — chords smear toward seasickness
  • C) Nothing — detune is inaudible beyond ten cents
  • D) The synth's pitch correction pulls the oscillators back together
Answer **B.** Detune works because slight frequency disagreement creates slow beating that your ear reads as a *section of players* — and real sections disagree by a little, not a lot. Push the disagreement too wide and the brain re-files the sound from "ensemble" to "broken." A is half right about speed but wrong that it stays musical. C is backwards — wider detune is *more* audible, not less. D doesn't exist; nothing rescues you from your own knob. The working zone runs roughly five to twenty cents, and the test is your ear, not the number.

6. Resonance on a filter is:

  • A) A boost right at the cutoff frequency — the filter emphasizing its own edge
  • B) A second filter one octave above the first
  • C) A stereo-widening control
  • D) Another name for the filter's slope
Answer **A.** Resonance feeds the filter's output back near the cutoff, creating a peak that travels with it — a little adds vowel-ish focus, a lot turns the cutoff into a playable whistle (the 303's acid squelch), and at the extreme many filters self-oscillate into a pure sine. B and C are fabrications. D names a different parameter — slope is the steepness of the roll-off in dB per octave, set by the filter design, not the resonance knob.

7. The practical difference between a 12 dB/oct and a 24 dB/oct low-pass filter is:

  • A) The 24 dB/oct filter is twice as loud
  • B) The 12 dB/oct filter removes twice as many harmonics
  • C) The 24 dB/oct filter cuts more steeply above the cutoff — decisive and classically "synthy" — while 12 dB/oct rolls off gently and reads as polite and transparent
  • D) The numbers describe the maximum resonance amount
Answer **C.** Slope is how fast content dies above the cutoff line: 24 dB/oct is the cliff, 12 dB/oct is the hillside. A confuses slope with gain. B is inverted — the *steeper* filter removes more, faster. D mislabels the parameter entirely. The chapter's starting habit: 24 for character, 12 for subtlety, ears overruling labels.

8. Keyboard tracking on a filter exists so that:

  • A) The synth stays in tune across the keyboard
  • B) The cutoff follows the pitch of the note you play, keeping the patch's character consistent — high notes open the filter more, so they don't go dull while low notes buzz
  • C) The DAW can record which keys you played
  • D) Velocity controls loudness correctly
Answer **B.** Real instruments naturally get brighter as pitch rises; a fixed cutoff betrays that expectation — low chords buzz through while high chords land muffled, and the patch feels subtly wrong in a way nobody can name. Around half tracking preserves character across the range. A is the oscillators' tuning, not the filter's. C describes MIDI recording. D describes a velocity routing, a different modulation entirely.

9. Sustain is the odd one out in ADSR because:

  • A) It's measured in milliseconds like the others
  • B) It only affects the filter
  • C) It happens after the key is released
  • D) It's a level, not a time — where the sound parks for as long as the key is held
Answer **D.** Attack, decay, and release are durations — how long each stage takes. Sustain is the resting *level* the decay falls to, held indefinitely until the key lifts. A is exactly the misconception the question hunts. B confuses the amp envelope with the filter envelope — both use ADSR. C describes release. If you missed this one, re-draw the pluck-versus-pad diagram from memory; it's load-bearing for everything else.

10. Which envelope makes a pluck — an instrument for rhythm whose notes are little events that get out of the way?

  • A) Attack 800 ms, sustain 100%, release 2 s
  • B) Attack 0 ms, decay 150–400 ms, sustain 0–20%, release about equal to the decay
  • C) Attack 0, decay 0, sustain 100%, release 0
  • D) Sustain 100% with a 3-second release
Answer **B.** Born loud, dies fast — the whole life of the note plays out whether you hold the key or not, which is what makes it rhythmic punctuation. A is the opposite story: a pad, arriving late and refusing to leave. C is the organ/init envelope — on while held, off when not, no story at all. D is a wash that pools over everything — atmosphere, not rhythm. Pluck versus pad isn't a sound difference; it's an envelope difference.

11. A funk bass that goes bwow — bright at the instant of the note, darkening into a round body — is built with:

  • A) A slow amp attack
  • B) An LFO routed to pitch
  • C) High resonance alone
  • D) An instant amp attack plus a snappy filter envelope: fast attack, quick decay, low sustain, healthy amount
Answer **D.** The two envelopes tell different stories on purpose: the amp envelope says "loudness is here immediately," the filter envelope says "brightness is born and dies in the first quarter second." A would delay the note itself — the opposite of funk. B is vibrato or, at audio rate, FM — pitch movement, not brightness movement. C adds an edge at the cutoff but no *story over time*; resonance is a seasoning, not an envelope. Brightness-over-time is most of a sound's identity, and the filter envelope is where you write it.

12. The behavioral difference between an envelope and an LFO is:

  • A) An envelope plays its shape once per note and stops; an LFO cycles endlessly
  • B) An LFO is audible as a tone; an envelope is not
  • C) Envelopes can only modulate the amplifier
  • D) LFOs trigger once per note; envelopes repeat forever
Answer **A.** One-shot versus loop — the same distinction you learned about samples in [Chapter 13](../chapter-13-programming-beats/index.md), now running the controls. B is wrong because an LFO runs *below* the floor of hearing; you hear it as motion, never as a tone (speed it into the audio range and you've left LFO territory for FM). C ignores the filter envelope and pitch envelopes — the 808's knock is an envelope on pitch. D states the truth exactly backwards.

13. The dubstep wobble bass is, at its core:

  • A) An LFO routed to pitch at about 5 Hz
  • B) A fast filter envelope retriggering on each note
  • C) A tempo-synced LFO rhythmically opening and closing a low-pass filter's cutoff
  • D) Sample-and-hold routed to pan
Answer **C.** A decade-defining sound in three words: LFO on cutoff — synced to note values so the brightness pulses *as rhythm*, locked to the drums. A is vibrato — pitch wobble, not brightness wobble. B plays its shape once per note; the wobble repeats in time regardless of where notes fall. D is the burbling random twinkle under sci-fi patches — gloriously useful, not a wobble. Synced movement is felt as groove; free-running movement is felt as weather.

14. In FM synthesis, new timbre is generated when:

  • A) One oscillator modulates another's frequency at audio rate, creating sidebands — the ratio between them sets which partials appear, and the modulation index sets how many (the brightness)
  • B) The modulator is mixed directly into the output alongside the carrier
  • C) A rich waveform is carved down by a steep filter
  • D) The wavetable position is scanned by an envelope
Answer **A.** Speed vibrato's wiring up past the audible floor and the ear stops hearing wobble and starts hearing *new harmonics* — sidebands above and below the carrier. Whole-number-ish ratios lean musical and harmonic; stranger ratios lean bell and metal; and the index behaves like a filter cutoff that *generates* instead of removes, which is why FM patches often need no filter at all. B misses the point — you usually never hear the modulator directly. C is subtractive's method (carving down, not building up). D is wavetable's trick, the next question's territory.

15. In wavetable synthesis, the position control:

  • A) Pans the sound across the stereo field
  • B) Selects which single-cycle frame of the table is currently playing — so modulating position makes the timbre itself travel while the note plays
  • C) Changes the pitch of the oscillator
  • D) Sets the number of simultaneous voices
Answer **B.** The wavetable oscillator is a flipbook of waveforms; position is the page you're on. Parked, it's an ordinary oscillator. Moved — by envelope, LFO, wheel, velocity — the sound transforms from the inside: a sine that becomes a buzz that becomes a vowel that becomes glass over one held note. That's motion *inside* the waveform, where subtractive movement always sounds like a filter doing something *to* a sound. A, C, and D name real synth parameters (pan, pitch, unison/polyphony) that have nothing to do with the table.

True/False with Justification (5 × 2 pts)

16. Raising resonance is a free upgrade: it adds focus and presence at the cutoff without costing anything elsewhere.

Answer **False.** There are no free moves — only moves whose costs you've heard and accepted. Every dB the resonant peak adds at the cutoff edge, you perceive as thinning everywhere else: the patch gets more *interesting* and *smaller* at the same time. Push far enough and the filter becomes a whistle riding the cutoff, then self-oscillates outright. The second point is for naming the specific cost (focus purchased with body), not just "everything has tradeoffs."

17. A factory preset is essentially a fact of the instrument — the way the synth "really" sounds from the factory.

Answer **False.** A preset is a stranger's decisions, frozen — somebody sat at a panel and made a series of small, nameable moves, then saved them. Patch memory itself only dates to instruments like the Prophet-5 in 1978; before that, a sound literally *was* its patch cords. The synth "really" sounds like whatever the next patch says it does. Full justification credit for some version of "saved human decisions, not hardware nature" — bonus respect for noting that this is exactly why presets can be *studied*: they're legible sentences in the mod-matrix grammar, written by someone you can learn from.

18. An LFO routed to pitch at around 5–6 Hz with a few cents of depth produces vibrato.

Answer **True.** That's the wiring of the humanizing wobble every singer and violinist applies by instinct — rate in the lazy-hand zone, depth at a whisker. The justification point is for the boundary fact: this only stays "vibrato" while the rate sits below the audible floor. Drag the same routing up into the audio range and the ear stops tracking cycles and fuses them into sidebands — new harmonics, not motion. Same wiring, different rate, different universe: that boundary *is* the doorway into FM.

19. In FM synthesis, as in subtractive, the filter does most of the timbre shaping.

Answer **False.** FM builds richness *up* instead of carving it down: the operator ratio writes the harmonic recipe and the modulation index acts as the brightness control — a cutoff that generates rather than removes. Many classic FM patches use no filter at all, which is precisely why the engine could produce glassy tines and bells that a saw through a low-pass never quite reaches. Justification credit for "ratio and index do the shaping" or "FM is additive in spirit — it generates sidebands instead of removing harmonics."

20. The static-bloom pad has no sub layer because pads never benefit from sub layers.

Answer **False.** The rule isn't pad dogma — it's lane discipline. "Static Bloom" the track already employs a sub bass (the [Chapter 9](../../part-02-tools-of-production/chapter-09-midi-virtual-instruments/index.md) sketch), and the sub lane takes one tenant per song: a pad with a basement would fight the bass every bar and the collision reads as mud, not power. In a sparse track with no bass instrument, a sine layer under a pad can be exactly right. The justification point is for citing the *arrangement-level* reasoning (who already owns the lane), not a blanket rule about pads. Jaylen learned this the direct way: he added the sub oscillator, played it against the track, and deleted it.

Short Answer (4 × 3 pts)

21. Two saws detuned ten cents apart sound wide and alive; one saw turned up twice as loud sounds like an angry doorbell. Explain the physics of why, and name the failure mode at each end of the detune range with its by-ear fix.

Answer The two oscillators sit at very slightly different frequencies, so their waveforms drift continuously in and out of phase — reinforcing, then partially canceling, at every harmonic, at slightly different rates. That slow interference churn is *beating*, the same physics as two almost-in-tune guitar strings throbbing, and the ear reads it as ensemble: real sections are never perfectly in tune, and micro-disagreement is what "twelve players" sounds like versus "one player, loud." Failure modes: too narrow (under roughly five cents) and the beating is too slow and subtle to register — widen by ear until shimmer appears; too wide (past roughly twenty cents) and the brain re-files ensemble as out-of-tune — narrow it until seasickness becomes motion. Both fixes are performed with ears, not numbers.

22. Describe a patch in which the amp envelope and the filter envelope deliberately tell different stories. Name what each envelope contributes and why this routing carries so much of a sound's identity.

Answer Two canonical examples (either earns full credit). The funk bass: amp envelope instant — loudness arrives with the note — while the filter envelope is snappy and separate (fast attack, quick decay, low sustain, amount cranked), so the note is born bright and immediately darkens: *bwow*. The bloom pad: amp attack slow (~0.8 s) so loudness swells in, filter envelope *slower still* (~1.2 s attack, meaningful amount), so brightness arrives after loudness and the chord unfolds — dark shimmer first, full light later. The amp envelope tells the loudness story; the filter envelope tells the brightness story; and because brightness-over-time is central to how we identify sounds — more identity than the waveform itself, usually — the filter envelope is the single most expressive routing in subtractive synthesis.

23. State the init-patch discipline, the three things building from init buys you, and when reaching for a preset is the professional choice rather than a compromise.

Answer The discipline: for sounds that matter, start from the init patch — one raw oscillator, filter open, organ envelope, nothing modulating — so you know every knob you turned. What it buys: (1) fixability — when the patch fights the mix, you know which of your moves owns the flaw; (2) variability — you hold the recipe, not the dish, so the pluck version or the ducked-out-of-the-vocal's-way version is minutes away; (3) literacy — after enough builds you hear synth sounds as *decisions* rather than objects, and preset browsers turn from casinos into libraries. Presets are professional when speed protects inspiration (the idea is hot and "warm keys" is eight seconds away), for supporting-cast roles, and as studies — reverse-engineering a great factory patch is elite training. The working compromise: presets and tweaks for the supporting cast, init builds for the signature roles. What presets cost is ownership — a sound you can't fix, can't vary, and share with every other owner of the same DAW.

24. List the three layers of the chapter's impact recipe, what each contributes, and which piece of Chapter 13 knowledge the first layer reuses.

Answer (1) The *thump*: a sine with a fast pitch envelope falling from high to low, tuned to the song's key — this is the 808/kick anatomy from [Chapter 13](../chapter-13-programming-beats/index.md) wearing a cape: a fundamental-only oscillator whose attack "knock" is an envelope on pitch, not loudness. (2) The *splash*: a burst of noise through a band-pass or open low-pass, medium decay, zero sustain — the explosive, pitchless event of arrival. (3) The *bloom*: a long-release element — dark detuned-saw chord stab or crash one-shot — that hands the energy back to the song over a second or two. Balance so the thump leads, bounce the composite to one audio file, and name it like you'll need it in a year, because you will.

Applied Scenario (5 pts)

25. A producer plays you a reference and says "build me this from scratch": a bass that speaks the instant the key goes down, with a bright snap that immediately darkens into a round, steady body; it gets noticeably brighter when the keyboardist digs in; held notes have a faint, slow shimmer of motion; and it must never crowd the vocal's presence zone or fall apart in mono. Describe your build from init: waveform choice(s) with reasoning, filter strategy, both envelopes, every modulation routing, and one tradeoff you're knowingly accepting. (Award the fifth point only if your answer includes both envelopes and the velocity routing.)

Answer **Oscillators:** one saw — full harmonic buffet for the filter to carve; add a square an octave down only if the body needs chest. Unison off, detune zero-to-whisker: basses want pitch focus, and tight focus is also your mono insurance. **Filter:** low-pass, 24 dB/oct for the decisive cut; cutoff moderate (a few hundred Hz up to ~800 Hz by ear) so the body stays round and the patch never parks content in the vocal's 2–6 kHz presence zone; modest resonance for definition; keyboard tracking around half so the character holds across the range. **Amp envelope:** attack 0–5 ms (speaks instantly), short decay to a healthy sustain (steady body), short release (notes get out of each other's way). **Filter envelope:** the snap — attack 0, decay ~150–250 ms, sustain low, amount generous: bright birth, dark body, the *bwow*. **Routings:** velocity → filter-envelope amount (~40%) so digging in opens the bloom — dynamics become timbre, not just loudness; one LFO → cutoff, very slow and shallow, free-running, for the faint shimmer on held notes (free-run, not synced — this is weather, not groove). **Tradeoff accepted:** keeping the cutoff conservative and the top darker buys the vocal its lane and mono solidity at the cost of solo sparkle — this bass will sound polite alone and perfect in the track, which is the right direction to be wrong. Scoring: 1 pt waveform reasoning, 1 pt filter strategy including the vocal-lane logic, 1 pt each envelope story, 1 pt the two routings with the velocity routing present.

Scoring

Score Verdict
38–42 Patch-literate. Run exercise C5 (recreate-a-preset) to convert vocabulary into reflex, then on to Chapter 15 — the edit is waiting.
30–37 Solid. Find which module cost you — generators and filters (questions 1–8) or envelopes and modulation (9–15) — re-skim that section, then build C1 and C2.
21–29 The signal path is half-loaded. Re-walk the spine diagram, do the fifteen-minute cutoff-and-resonance sweep ritual, run init drills C1–C2, and retake.
Below 21 No shame — this chapter compiles through fingers, not eyes. Re-read "The Subtractive Core" with a synth open and your hands on the controls, then come back. The knobs will teach what the prose couldn't.