04 Introduction. Some Facts on Vibrations. Acoustic Variables and Basic Relations. Plane Waves, Attenuation. Spherical Wave and Sound Radiation. Reflection and Refraction. Diffraction and Scattering. Sound Transmission in Pipes and Horns. Sound in Closed Spaces. Sound Waves in Isotropic Solids. Music and Speech. Human Hearing. Room Acoustics. Building Acoustics . Basics of Noise Control. Underwater Acoustics and Ultrasound. Electroacoustic Transducers. Microphones. Loudspeakers and Other Electroacoustic Sound Sources. Electroacoustic Systems.