Noise Criteria (NC) curves define acceptable background noise levels across octave bands for each studio space. This analysis maps our room targets against standard NC curves to verify HVAC silencing and transmission-loss budgets meet professional recording standards.
Each gray dashed line represents a standard NC rating. Colored lines show target curves for each room. Hover over any curve for exact dB values. Click room buttons to isolate individual targets.
Each room's NC target is split into an HVAC noise allocation, a transmitted noise allocation, and a safety margin. The stacked bar visualizes how the total budget is divided.
Each duct run is fitted with an inline silencer sized to meet its room's NC allocation for HVAC noise.
| Run | Serves | Length | Attenuation | Max Velocity | NC Max | Status |
|---|
The tangent method: An NC rating is determined by plotting the measured sound pressure level at each octave band (63 Hz through 8 kHz) and finding the highest standard NC curve that the measured spectrum is tangent to. The room's NC rating equals that curve. Even a single band exceeding a curve disqualifies that rating.
Why VO Live needs NC-20: Voice-over recording captures the most dynamic range and the quietest source material. At NC-25, residual HVAC rumble becomes audible in close-mic spoken word. NC-20 provides sufficient headroom for whispered narration without noise-floor intrusion, which is why VO Live receives the longest silencer (1500 mm, 40 dB attenuation) and lowest terminal velocity (1.5 m/s).
Silencer length vs. attenuation: Longer silencers provide more internal surface area for absorptive baffles, yielding higher broadband attenuation. The 1500 mm silencer on Run A achieves 40 dB of insertion loss for VO Live (NC-20), while the 1000 mm silencers on Runs B and C achieve 25 dB, and the 500 mm unit on Run D provides 15 dB — adequate for Editing's more relaxed NC-35 tolerance.