Chapter 10 Quiz

Closed book on the first pass — that's the honest score, and this chapter's material is exactly the kind that feels learned before it is. Multiple choice, then true/false with justification (the justification is most of the points), then short answer, then one applied scenario: a described room you must diagnose like the engineer this chapter is building. Answers hide under each Verify fold. Scoring guide at the end.

Multiple Choice

2 points each.

1. The threshold concept "your room is part of your monitoring chain" means:

A) You should buy monitors designed for your room's size B) The room applies processing — peaks, dips, reverb, echoes — to everything between the speaker cone and your ear, with no bypass C) Room correction software must be installed before mixing D) Bigger rooms always sound more accurate than small ones

2. Comb filtering at the mix position is caused by:

A) Cheap monitors with uneven frequency response B) The direct sound summing with delayed reflected copies of itself at your ears, carving evenly spaced notches and peaks C) Standing waves between parallel walls D) Digital aliasing in the converter

3. The mirror trick finds:

A) Room modes B) Flutter echo pairs C) First-reflection points — every wall and ceiling spot that bounces the monitors' sound to your ears D) The best corner for bass traps

4. A room mode (standing wave) forms when:

A) Two speakers play the same frequency in phase B) A whole number of half-wavelengths fits exactly between two parallel surfaces, so the reflections reinforce into a stable resonance C) The room's RT60 exceeds one second D) Sound reflects off more than three surfaces at once

5. You cannot fix a null at your chair with EQ because:

A) Consumer EQs don't reach below 100 Hz B) The boost would damage your woofers C) The null is a cancellation — boosting makes both the direct wave and its canceling reflection bigger, so they cancel just as completely while everywhere else booms louder D) Nulls only affect frequencies above the Schroeder frequency

6. Using the sidebar's formula, the lowest axial mode of a 10-foot dimension sits near:

A) 28 Hz B) 57 Hz C) 113 Hz D) 226 Hz

7. Small rooms have worse bass problems than large rooms because:

A) Small rooms reflect more total energy B) Their first modes land high enough to sit right in the musical bass range, with wide empty gaps between modes — a few isolated resonances instead of a dense, averaging forest C) Drywall absorbs more bass than concrete D) Small rooms have higher RT60 times

8. An 8 × 10 × 8-foot room is acoustically unlucky because:

A) It's too small to develop any room modes B) The matching 8-foot dimensions produce identical modal series, doubling the energy at 71 Hz, 141 Hz, and up C) Ten feet is a forbidden dimension in studio design D) Square rooms have no first-reflection points

9. The fundamental difference between acoustic treatment and soundproofing is:

A) Treatment changes how the room sounds inside; soundproofing stops sound crossing a boundary — and the second is construction (mass, decoupling, airtight sealing) B) Treatment is for studios; soundproofing is for venues C) They're the same thing at different price points D) Soundproofing handles high frequencies; treatment handles low ones

10. Thin foam panels disappoint at 80 Hz because:

A) Foam is the wrong color to absorb bass B) An 80 Hz wave is around 14 feet long, and near a wall its air barely moves for many inches — a 2-inch absorber sits inside the wave's dead zone, with nothing moving for friction to grab C) Foam only works above 10 kHz D) Bass waves travel too fast for foam to react

11. Bass traps go in corners because:

A) Corners are usually unused space B) Corners are where boundaries meet, so they sit on the pressure maps of every mode family at once — one stack of material collects from the whole bass war C) Bass waves originate in corners D) Corner placement prevents flutter echo

12. Flutter echo is best described and best fixed as:

A) A low-frequency boom; fix with corner traps B) A sharp sound ping-ponging between two hard parallel surfaces, heard as a metallic zing; fix with soft absorption on one of the pair C) A delay plugin artifact; fix in the DAW D) Cone breakup in small woofers; fix with better monitors

13. The "38% rule" for listening position is best treated as:

A) A law derived from the speed of sound that should never be violated B) A starting zone that dodges the halfway and quarter-point null geography of the strongest length modes — then walk-tested with a bass-heavy reference, because the walk test outranks the fraction C) A marketing convention with no physical basis D) The minimum distance from your monitors in all rooms

14. The tracking doctrine "when in doubt, record drier — especially vocals" exists because:

A) Dry recordings use less disk space B) Reverb plugins sound better than all real rooms C) A room's contribution prints permanently into the take — you can add a space you don't have in the mix (Chapter 24), but you cannot cleanly subtract one you do D) Singers perform better in dead rooms

15. Diffusion is the treatment you postpone in a bedroom studio because:

A) It's illegal in residential buildings B) Diffusion needs distance for its scattered field to even out, and it solves a too-dead-room problem that no untreated bedroom has C) Diffusors only work on bass frequencies D) Absorption and diffusion can't coexist in one room

True/False with Justification

2 points each: 1 for the call, 1 for the justification — the justification is the part this chapter cares about.

16. Foam wedge panels marketed as "soundproofing" will meaningfully reduce the sound your neighbors hear.

17. Since the exact center of the room's width is the width-mode's null line, you should shift your chair a foot to one side to escape it.

18. RT60 is the time it takes sound in a room to decay by 60 dB — informally, how long the room keeps talking after you stop.

19. A closet full of hanging clothes makes an ideal vocal booth, since the clothes absorb sound.

20. Damping a room mode with corner traps lowers its peaks AND partially fills its nulls.

Short Answer

4 points each.

21. In the chapter's hook, Jaylen swaps his left and right monitors to test whether the scuffed one is faulty, and the problems don't move. Explain what that experiment proved and why it's such an efficient diagnostic.

22. What is the blow test, what does it check, and what does failing it cost an acoustic panel?

23. After treating your room, the chapter tells you to play your own old mixes and warns they will sound wrong. Explain why, and what the specific wrongness tells you.

24. Your room measures 11 × 13 × 8 feet. Compute the lowest axial mode for each dimension, state whether this room stacks modes, and name the one piece of furniture-free "treatment" you'd apply before spending anything.

Applied Scenario

8 points.

25. A friend sends you this, with photos:

"Set up my first studio in the spare room — it's 12 × 12 with an 8-foot ceiling. Desk is in the corner, angled across it, because that's where the outlet is, so the left speaker is a foot from the wall and the right one is out in open space. I covered the wall behind the desk in foam wedges I got cheap. Mixes sound boomy on one note like the room is humming, vocals I record in there sound like they're in a cardboard box, the stereo image is soup, and in the car everything is thin with no low end. Also the neighbors still complain, so the foam is fake I guess? What do I buy next?"

Diagnose at least four distinct problems using this chapter's vocabulary, explain what the foam is and isn't doing, and write the plan — free moves first, then roughly $150 of spending — in the order this chapter argues.

Scoring