Acoustics and Lighting

Acoustics and Lighting

These two disciplines govern the sensory environment of a building: how it sounds and how it looks.

Architectural Acoustics

Room Acoustics

Dealing with sound within a room.

• Reverberation Time (RT60): Time for sound to decay by 60 dB.
  • High RT60 (Echoey): Good for music (Cathedrals).
  • Low RT60 (Dead): Good for speech (Classrooms).
• Absorption: Soft materials (carpets, acoustic tiles) absorb sound energy.
• Diffusion: Irregular surfaces scatter sound to prevent hot spots.

Sound Isolation

Dealing with sound transmission between rooms.

• STC (Sound Transmission Class): Rating of a barrier's ability to block sound.
• Mass Law: Heavier walls block more sound.
• Decoupling: Separating wall layers to break vibration paths.

Lighting Design Strategies

Daylighting

Using natural light to reduce energy and improve well-being.

• Clerestories: High windows.
• Light Shelves: Reflect light deeper into the room.
• Solar Tubes: Pipe sunlight into interior spaces.

Artificial Lighting Design

• CRI (Color Rendering Index): How accurate colors look under the light (0-100). Sunlight = 100.
• CCT (Correlated Color Temperature):
  • Warm White (2700K): Relaxing, residential.
  • Cool White (4000K): Productive, offices.
  • Daylight (6500K): Clinical, industrial.

Application: Calculating Reverberation Time

Sabine's Formula is used to estimate RT60.

Summary

Good acoustic and lighting design requires a balance of physics and perception. Controlling noise improves productivity, while quality lighting enhances mood and visibility.