- 2076 Bhadra · 2+6 marks
Acoustics, acoustic defects and remedies
Short answer
Acoustics is the science of sound, dealing with hearing conditions and noise control. Defects include echo (remedy: absorbent on reflecting wall), excess reverberation (add absorbers), sound foci (avoid concave surfaces), dead spots (reflectors), echelon effect (irregular spacing), resonance (damping), and sound shadow (limit balcony depth).
Define the term acoustics and explain in brief general acoustic defects, and suggest remedial measures of each defect.
Acoustics is the science of sound, covering its production, transmission, absorption and reception. In buildings, it deals with providing good hearing conditions and controlling noise.
Acoustic defects and remedies
| Defect | Cause | Remedy |
|---|---|---|
| Echo | Hard, distant, parallel reflecting walls; delay of reflected sound over about 0.1 s | Absorbing material (acoustic plaster, panels, curtains) on the reflecting wall; irregular wall shapes |
| Excess reverberation | Too little absorption, so sound persists | Add absorbers: carpets, curtains, perforated boards, upholstered seats; |
| Sound foci | Concave surfaces (domes, curved walls) focus sound | Avoid concave shapes; use absorbing or convex diffusing finishes |
| Dead spots | Areas not reached by sound because of focusing and shadow | Reflectors and correct hall shape; proper speaker placement |
| Echelon effect | Regular reflections from stairs, railings, ribs | Absorbent covering, irregular spacing |
| Resonance | Panel or air space vibrating at natural frequency | Damping materials, avoid resonant cavities |
| Sound shadow | Balcony or beam blocking sound | Limit balcony depth (depth not more than twice the height of opening); raked seating |
| External noise and poor insulation | Traffic and neighbours | Sound-insulating walls, windows and doors; site planning with buffers |
Design of the hall should give uniform loudness, right reverberation time, and freedom from echo and noise.
✓ Answer checked by Claude Opus 5.5 (high effort)
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