What to measure
Great rooms are verified. The essentials are frequency response, decay, and level matching. Measurements help you separate “taste” from “physics”.
Tools you’ll use
- Measurement mic (calibrated omni)
- Audio interface / preamp with phantom power
- Sweep software (e.g., REW or equivalent)
- SPL meter (or mic-based SPL calibration)
Mic placement basics
For a control room, measure at the listening position first, then take spatial averages around it. For theaters, measure multiple seats and focus on consistency.
Reading the graphs
Frequency response
Look for large peaks/nulls (especially below 300 Hz). Small ripples are normal. Nulls are typically position/phase problems; treatment and placement help more than EQ.
Waterfall / decay
Long ridges in the bass indicate modal ringing. This is a time-domain issue. Bass traps and room strategy are the primary fixes.
RT by frequency band
Many untreated rooms have short high-frequency RT but long low-frequency decay — the room feels boomy yet bright. Balanced decay tends to sound more natural and mixes translate better.
Basic calibration steps
- Set speaker placement and toe-in.
- Match speaker levels (pink noise, SPL target).
- Align subwoofer phase/timing to mains (if applicable).
- Apply minimal EQ after treatment/placement are optimized.
- Validate with measurements and reference tracks.
Common pitfalls
- Relying on EQ to solve modal decay.
- Measuring too loud or too quiet (poor signal-to-noise).
- Ignoring multiple positions (single-point measurement bias).