Unit 1: Building Acoustics
Introduction - Terminology and unit. Characteristics of audible sound – Propagation, Velocity, Frequency, Pitch, Quality/timbre, Loudness and Intensity. Behavior of audible sound in enclosures – Reflection,Absorption, Diffraction andTransmission of sound. Common acoustical defectsand recommended remedies– Echo, Sound foci, Dead spots, Sound shadows, Resonance, Insufficient loudness, External noise and Reverberation. Sabine’s expression for calculation of Reverberation time. Absorbents and absorption coefficient. Noise control – Noise and its types, Noise pollution. Sources of indoor noise, Indoor noise levels,Planning and design against indoor noise. Sources of outdoor noise, Traffic noise levels, Planning and design against outdoor (traffic & buildings in built-up area) noise. Identification of various sources of noise and recommendations to control them in various types of buildings e.g. – Residential, Educational, Hospital, Office, Hotels & Hostels, Industrial, Laboratories & Test houses, Miscellaneous buildings etc. Constructional measures for sound insulation of buildings – Materials, Hollow & composite wall construction, Floors&Ceilings. Properties of good acoustical materials. Sound system – Sound reinforcement system, Public address system. Familiarization and understanding of sound system equipment specification e.g. Amplifiers, Microphones, Speakers, Mixers, Conference systems and accessories. Acoustical design principles and factors– Acoustical design principles for Auditoriums, Cinema halls, Conference rooms etc. and factorsviz. Site selection & planning, Dimensions, Shape, Seats & seating arrangements, Treatment of interior surfaces, Reverberation & sound absorption. SECTION – B, APPLICATION