Chapter 7 Quiz — Microphones

Closed book, honest effort, no shame in wrong answers — wrong answers are a map of what to reread. Multiple choice: 1 point each. True/False: 2 points (1 for the verdict, 1 for the justification — a correct coin-flip with a wrong reason earns half). Short answer: 3 points each. Applied scenario: 5 points. Total: 42. Scoring table at the end.

Section 1 — Multiple Choice (15 × 1 pt)

1. A dynamic moving-coil mic generates its signal by:

  • A) Measuring capacitance changes across a charged gap
  • B) Moving a coil of wire through a magnetic field
  • C) Vibrating a corrugated aluminum ribbon between magnet poles
  • D) Converting pressure directly into digital samples
Answer **B.** The diaphragm carries a coil through a permanent magnet's field — a loudspeaker run in reverse. (A is the condenser; C is the ribbon; D is nobody — conversion to digital happens at the converter, per Chapter 3.)

2. The main physical reason a dynamic mic softens fast transients is:

  • A) Its grille blocks high frequencies
  • B) It lacks phantom power
  • C) The moving mass of the coil resists rapid starts and stops
  • D) Its output is balanced
Answer **C.** Mass is the personality: the coil makes the moving system heavier, so the fastest edges of a sound get rounded. The same mass is why it tolerates brutal SPL.

3. A condenser microphone requires phantom power because:

  • A) Its magnet needs recharging
  • B) The capsule needs a polarizing charge and the internal head amp needs supply power
  • C) Balanced cables don't work without it
  • D) It boosts the signal to line level
Answer **B.** Two jobs, one 48 V feed: charge the capacitor gap so capsule motion becomes voltage, and power the electronics that make that faint signal usable. (D is false — the output is still mic level; the preamp does the lifting.)

4. Which mic family is figure-8 by its basic physics, before any design tricks?

  • A) Dynamic moving-coil
  • B) Large-diaphragm condenser
  • C) Ribbon
  • D) Small-diaphragm condenser
Answer **C.** Both faces of the ribbon are open to the air, so it hears front and back equally and rejects the sides — figure-8 from birth.

5. The engineer's way to choose a polar pattern is by:

  • A) Which pattern captures the most signal
  • B) Which pattern is most expensive
  • C) What the pattern lets you reject, and where its nulls can point
  • D) Whatever the mic's manual recommends for the source
Answer **C.** Buy the null, not the lobe: in real rooms you're drowning in sound you don't want, and the pattern is your free rejection tool.

6. The only polar pattern with no proximity effect is:

  • A) Cardioid
  • B) Omnidirectional
  • C) Figure-8
  • D) Hypercardioid
Answer **B.** Omni's sealed single face responds to pressure itself rather than comparing front to back — no comparison, no proximity bass. Figure-8 sits at the opposite extreme, with the strongest proximity effect.

7. A hypercardioid's true dead zones are located:

  • A) Directly behind the mic
  • B) Directly in front of the mic
  • C) At the sides, exactly 90° off-axis
  • D) Toward the back corners, roughly 110–125° off the front axis
Answer **D.** The nulls sweep forward from the cardioid's 180° position — and a small rear lobe appears directly behind, which is why aiming a monitor at the mic's tail backfires.

8. Proximity effect happens in directional mics because, at very close range:

  • A) The room's reflections overwhelm the capsule
  • B) The level difference between the diaphragm's front and back becomes large, upsetting a balance tuned for distant sources
  • C) The diaphragm physically touches the source
  • D) Phantom power voltage rises
Answer **B.** Directional mics respond to the front-versus-back difference. Far away that difference is mostly timing; up close the inverse-square level drop across millimeters takes over, and the design's compensation over-delivers bass.

9. "Vocal mics" commonly build in a presence peak around:

  • A) 200 Hz
  • B) 1 kHz
  • C) 5 kHz
  • D) 15 kHz
Answer **C.** A few dB of lift in the high-mids (centered in the 3–6 kHz region) flatters consonants, articulation, and cut-through — prepaid EQ aimed at intelligibility.

10. Off-axis coloration means that sound arriving from the side of a mic is:

  • A) Only quieter than on-axis sound
  • B) Delayed but tonally identical
  • C) Subject to a different — usually worse — frequency response than on-axis sound
  • D) Automatically removed by the polar pattern
Answer **C.** The pattern is a different shape at every frequency, so off-axis arrivals get re-EQ'd — typically duller and lumpier. It's quieter *and* recolored; the recoloring is the part that sounds cheap.

11. Your loud source sounds distorted at the capture even though DAW meters never approach 0 dBFS. The most likely cause is:

  • A) The converter clipped
  • B) The mic's capsule or internal electronics overloaded, upstream of the meters
  • C) Your buffer size is too small
  • D) The pop filter is absorbing transients
Answer **B.** Mic-stage overload happens before the preamp and converter; dBFS meters can't see it. Fixes: engage the pad, or add distance. (C causes clicks/dropouts, not crunch; D isn't a thing.)

12. The chapter's "three dials" of placement are:

  • A) Gain, pan, fader
  • B) Distance, axis, height
  • C) Pattern, pad, filter
  • D) Attack, release, ratio
Answer **B.** Distance (room share + proximity), axis (treble shading), height (which part of the source's recipe dominates). (D is [Chapter 23](../../part-05-mixing-foundations/chapter-23-compression/index.md) knocking early.)

13. The primary acoustic reason to work a mic closer in a bad-sounding room is:

  • A) Closer always sounds brighter
  • B) It raises the direct-to-room ratio, pushing the room down relative to the source
  • C) It increases the mic's sensitivity
  • D) It removes the need for a pop filter
Answer **B.** Direct sound falls off fast with distance; the room's wash stays roughly constant. Closeness is poor-man's room treatment — billed in proximity bass you manage on purpose.

14. Which stereo pair geometry is the safest when the result must survive mono playback, and why?

  • A) Spaced pair — widest image
  • B) ORTF — the standard compromise
  • C) XY — capsules share one point, so there are almost no timing differences to cancel
  • D) Two mics at random positions — diversity helps
Answer **C.** Coincident capsules build their image from level differences, not timing, so a mono sum has nothing to cancel. Spaced pairs lean on timing — width in stereo, potential cancellation in mono.

15. Besides stopping breath blasts, the pop filter's second job in this chapter is:

  • A) Improving the mic's frequency response
  • B) Acting as a physical distance-keeper so proximity effect stays consistent take to take
  • C) Providing shock isolation from the stand
  • D) Increasing SPL handling
Answer **B.** Set at your chosen working distance, it turns the distance decision into furniture — the singer can't drift, so the low end can't wander. (C is the shock mount's job.)

Section 2 — True / False, with Justification (5 × 2 pts)

16. True or false: A cardioid mic's rear null works equally well at all frequencies.

Answer **False.** The null weakens at low frequencies — long wavelengths wrap around the mic (and everything else), and patterns relax toward omni in the bass. The null is a notch, not a force field, and it's a *treble-favoring* notch at that.

17. True or false: For stacked vocal harmonies, recording each layer at noticeably different mic distances is a good way to add variety.

Answer **False.** Different distances mean different proximity-effect bass signatures (and different room shares) per layer, so the stack refuses to gel — each voice carries a mismatched low end no static EQ can reconcile. Match the distance; create variety with performance, height, or arrangement instead.

18. True or false: A ribbon mic's main enemy on loud sources is sound pressure level itself.

Answer **False.** Ribbons typically handle high *level* fine; their enemy is moving *air* — blasts from kick ports, cab gusts, point-blank plosive breath — which can stretch the ribbon. Level and wind are different threats, and the ribbon fears the second.

19. True or false: Much of what separates expensive microphones from budget ones is consistency of off-axis response rather than dramatically better on-axis sound.

Answer **True.** Premium capsules hold something close to their tonal balance as sources move off the line; budget capsules re-EQ off-axis arrivals raggedly. Since rooms and bleed arrive almost entirely off-axis, this unprinted spec predicts real-world disappointment better than the printed ones.

20. True or false: Because placement matters so much, the mic's frequency response is irrelevant to the final sound.

Answer **False — and watch the overcorrection.** Placement is the bigger lever, but the response curve is real prepaid EQ: a presence peak on an already-bright voice records a harshness problem permanently. The chapter's claim is placement *beats* purchase, not placement *erases* the mic. Both are decisions; one is free and reversible before capture, which is why it comes first.

Section 3 — Short Answer (4 × 3 pts)

21. Explain the dynamic-versus-condenser choice for a vocal in an untreated bedroom, citing one property of each family and one placement consequence.

Answer A dynamic's low sensitivity and close working style mean the room contributes proportionally little — its relative deafness to ambience is protection in a bad room. A condenser's near-massless diaphragm hears detail and air beautifully but hears the untreated room just as beautifully, mostly through its off-axis pickup. Placement consequence: the dynamic gets worked close (3–5 in, pop filter, proximity managed deliberately); if the condenser is used anyway, the fix is placement — dead material behind the singer, closer working distance, null aimed at the liveliest wall.

22. Your singer's takes vary in low-end weight from phrase to phrase. Name the phenomenon, the mechanism, and two different fixes from the chapter.

Answer Proximity effect, modulated by the singer's swaying — distance to a directional mic is changing, so the bass boost rides up and down. Mechanism: up close, the front-versus-back level difference grows, tipping the directional capsule's balance toward bass, more with every inch closer. Fixes: lock the distance physically (pop filter as distance-keeper, tape mark on the floor, coaching), or switch to omni — the pattern with no proximity effect — accepting more room in the take as the price.

23. State the three questions of the rejection-first pattern-selection method, in order, and apply them in one sentence to a podcast host whose desk faces a window with a busy street behind it.

Answer (1) What's the source, and does it move? (2) What's the enemy? (3) Where can a null physically point? Application: the source is a stationary close-worked voice, the enemy is the window/street directly ahead of the host — so a cardioid pointed *at the host, away from the window* puts its rear null toward the noise: host on the window side of the desk, mic facing them with its back to the glass, worked at broadcast distance.

24. Why does the chapter call a mic's frequency response "prepaid EQ," and what does that framing imply about pairing mics with sources?

Answer The curve is an EQ decision applied before capture, permanently — a presence peak is a 5 kHz-region boost you bought at the factory and print into every take. Implication: choose the mic the way you'd choose a starting EQ move — complement the source rather than doubling its existing traits: dark voice → brighter/peaked mic; bright, edgy voice → flatter or darker mic (or ribbon). The pairing logic gets its full workout in Chapter 11.

Section 4 — Applied Scenario (1 × 5 pts)

25. A friend is recording an EP in a spare bedroom: one singer (bright, slightly harsh voice), one acoustic guitar, occasionally both at once, live. Gear: one cardioid LDC, one cardioid dynamic, a 2-input interface, one pop filter, blankets available. The room: bare walls, a window, a closet of clothes. Design the capture for the live duo take: who gets which mic and why (family + response logic), where each performer sits relative to the room, all three dials for each mic, where each null points, and the single biggest bleed compromise you're knowingly accepting. Five defensible decisions, five points.

Answer (one strong solution — others can earn full marks with justification) (1) **Voice → the dynamic**, worked close at 3–4 in with the pop filter: the bright/harsh voice does *not* want a typical LDC's presence lift, the dynamic's polite top calms the edge at capture, and close working distance maximizes voice-over-guitar separation in a live take. (2) **Guitar → the LDC** at the 12th fret, 8–10 in, tilted slightly toward the body: the guitar benefits from the condenser's detail and air, and it's a quieter, steadier source the condenser flatters. (3) **Room staging:** both performers face into the closet/blanket corner — dead material behind each mic's *field of view*; the window wall gets nobody's on-axis path. Hang a blanket between the two performers' lines of sight to each other's mic if positioning allows. (4) **Nulls:** vocal mic's rear null aims toward the guitar as much as geometry permits; guitar mic's null toward the singer — cardioids facing *away* from each other's sources in a roughly back-to-back arrangement, performers angled so each mic's rear faces the other's source. (5) **The accepted compromise:** bleed cannot be eliminated with two cardioids in one room — accept guitar-into-vocal-mic bleed as the lesser evil (the close-worked dynamic keeps the voice dominant), and commit: live-take bleed means the pair's *balance* decisions are being made now, at capture, not in the mix. Bonus credit for noting distances must stay consistent across takes (proximity matching) or for proposing a recorded test of both mic assignments before committing — the blind-test habit.

Scoring

Score Verdict
38–42 Ready. Your capture plan will be built on bedrock — go write it.
30–37 Solid. Reread the sections behind your misses (patterns and proximity are the usual suspects), then run DAW Lab C1–C2.
21–29 The concepts are loaded but not yet wired together. Reread "The Science" with the diagrams, then redo the quiz in two days — spaced, like the book taught you.
Below 21 No verdict except: the chapter deserves a second pass, this time doing the 🔄 checkpoints honestly. The labs will make it physical — start with C1, the distance ladder.

Whatever you scored: the exercises' Part C is where this knowledge becomes hands. The quiz measures the map, not the territory.