Acoustics: Sounds Right

All of us speak and hear people blabber every day [Sigh.]. Those of us who are lucky also listen to music every day and some of us even play music. However, very few understand the theory behind music and sound. Let me blow your mind and take you on a journey into Acoustics - a branch of physics concerned with the properties of sound. Let us dive deep into the human ear and brush against the Stereocilia. By the end of this course you will know how to measure the exact frequency and amplitude of sound when your spouse yells at you, which we will term “objectionable information carrying sound”. More specifically: In section 1: “Fundamentals of Sound” we will explore The Sine Wave, Sound in Media, Particle Motion, Propagation of Sound, Speed of Sound, Wavelength and Frequency, Complex Waves, Harmonics, Phase, Partials, Octaves, Spectrum, Electrical, Mechanical, and Acoustical Analogs. In section 2: “Sound Levels and the Decibel” we will explore Ratios versus Differences, Expressing Numbers, Logarithms, Decibels, Reference Levels, Logarithmic and Exponential Forms Compared, Acoustic Power, Using Decibels, Sound-Pressure Level, Loudspeaker SPL, Microphone Specifications, Line Amplifier, General-Purpose Amplifier, Concert Hall, Combining Decibels, Measuring Sound-Pressure Level, and Sine-Wave Measurements. In section 3: “Sound in the Free Field” we will explore The Free Field, Sound Divergence, Sound Intensity in the Free Field, Sound Pressure in the Free Field, Examples: Free-Field Sound Divergence, Sound Fields in Enclosed Spaces, and Hemispherical Field and Propagation. In section 4: “The Perception of Sound” we will explore Sensitivity of the Ear, Ear Anatomy, The Outer Ear, Directional Cues, The Ear Canal, The Middle Ear, The Inner Ear, Stereocilia, Loudness versus Frequency, Loudness Control, Area of Audibility, Loudness versus Sound-Pressure Level, Loudness and Bandwidth, Loudness of Impulses, Audibility of Loudness Changes, Pitch versus Frequency, Pitch, The Missing Fundamental, Timbre versus Spectrum, Localization of Sound Sources, Binaural Localization, Law of the First Wavefront, The Franssen Effect, The Precedence Effect, Perception of Reflected Sound, The Cocktail-Party Effect, Aural Nonlinearity, Subjective versus Objective, and Occupational and Recreational Deafness. In section 5: “Signals, Speech, Music, and Noise” we will explore Sound Spectrograph, Speech, Vocal Tract Molding of Speech, Formation of Voiced Sounds, Formation of Unvoiced Sounds, Frequency Response of Speech, Directionality of Speech, Music, String Instruments, Wind Instruments, Nonharmonic Overtones, Dynamic Range of Speech and Music, Power in Speech and Music, Frequency Range of Speech and Music, Auditory Area of Speech and Music, Noise, Noise Measurements, Random Noise, White and Pink Noise, Signal Distortion, Harmonic Distortion, Resonance, and Audio Filters. In section 6: “Reflection” we will explore Specular Reflections, Flutter Echoes, Doubling of Pressure at Reflection, Reflections from Convex Surfaces, Reflections from Concave Surfaces, Reflections from Parabolic Surfaces, Whispering Galleries, Standing Waves, The Corner Reflector, Mean Free Path, Perception of Sound Reflections, The Effect of Single Reflections, Perception of Spaciousness, Images, and Echoes, Effect of Angle of Incidence, Signal Type, and Spectrum on Audibility of Reflection.