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Fundamentals of Acoustics

Fundamentals of Acoustics. Instructor: Prof. Nachiketa Tiwari, Department of Mechanical Engineering, IIT Kanpur. This course provides the basics of acoustics, and covers topics in the field: the nature of sound, sound terminology, overview of some important mathematical concepts like complex algebra and complex time signals, wave equation, sound propagation in a tube, acoustic power, spherical waves, interference of sound sources, noise reduction by mass attenuation, designing mufflers, Fourier series and (Fast) Fourier Transforms, microphones, weighting, loudness, octave band analysis, reverberation time, sound transmission class, and noise reduction coefficient. (from nptel.ac.in)

Lecture 03 - Nature of Sound

This lecture covers the following topics: Beats Phenomena; Typical Sound Pressures; the Need for Logarithmic Scales.


Go to the Course Home or watch other lectures:

Introduction and Terminology
Lecture 01 - Course Overview
Lecture 02 - Introduction
Lecture 03 - Nature of Sound
Lecture 04 - The Decibel Scale
Lecture 05 - Key Terms in Acoustics
Lecture 06 - Adding Decibels
Concept Review
Lecture 07 - Important Mathematical Concepts - Complex Algebra
Lecture 08 - Important Mathematical Concepts - Complex Time Signals
Lecture 09 - Important Mathematical Concepts - Transfer Function
Lecture 10 - Important Mathematical Concepts - Pole Zero Plot
Lecture 11 - Important Mathematical Concepts - Bode Plot for Simple Pole
Lecture 12 - Important Mathematical Concepts - Bode Plot for Simple Zero
Wave Equation
Lecture 13 - Bode Plots (Magnitude) for Complex Transfer Functions
Lecture 14 - Momentum Equation for 1-D Sound Propagation
Lecture 15 - Continuity Equation for 1-D Sound Propagation
Lecture 16 - Gas Law for 1-D Sound Propagation
Lecture 17 - 1-D Sound Wave Equation
Lecture 18 - Solution for 1-D Sound Wave Equation
Transmission Line Equations
Lecture 19 - Waveguide
Lecture 20 - Sound Propagation in a Semi-Infinite Tube
Lecture 21 - Transmission Line Equations for Pressure and Velocity
Lecture 22 - Sound Propagation in a Closed Tube
Lecture 23 - Sound Propagation in Closed Tubes
Lecture 24 - Sound Propagation in a Open Tube
1-D Waves
Lecture 25 - Instantaneous Power
Lecture 26 - Instantaneous Power in a L-R Circuit
Lecture 27 - Power Factor, and Acoustic Power
Lecture 28 - Power Flow into an Infinitely Long Tube
Lecture 29 - Point Sources of Sound
Lecture 30 - Relations for Outward Travelling Spherical Acoustic Wave
Power and Spherical Waves
Lecture 31 - Specific Acoustic Impedance for a Closed Tube
Lecture 32 - Specific Acoustic Impedance for an Open Tube and an Infinitely Long Tube
Lecture 33 - Specific Acoustic Impedance for a Tube with Imperfect Termination
Lecture 34 - Kundt's Tube
Lecture 35 - Volume Velocity
Lecture 36 - Comparison of Impedances for a Radially Propagating Wave and a Planar Wave
Spherical Waves and Interference
Lecture 37 - Interference of Two Sound Sources
Lecture 38 - Interference of Two Sound Sources with Zero Phase Difference
Lecture 39 - Interference of Four Sound Sources with Zero Phase Difference
Lecture 40 - Interference of n-Sound Sources with Zero Phase Difference
Lecture 41 - Directivity Pattern, Directivity Factor, Directivity Index
Lecture 42 - Complex Power, Pressure and Velocity for a Spherical Source
Directivity and Mufflers
Lecture 43 - Noise Reduction by Mass Attenuation
Lecture 44 - Noise Reduction - Pressure Ratio
Lecture 45 - Noise Reduction - Velocity of Wall
Lecture 46 - 3 Media Problem - Introduction
Lecture 47 - 3 Media Problem - Applying Boundary Conditions
Lecture 48 - 3 Media Problem - Special Cases
Sound in Rooms
Lecture 49 - Mufflers
Lecture 50 - Designing of Reactive Mufflers
Lecture 51 - Designing of Dissipative Mufflers
Lecture 52 - Time and Frequency Domain Representation of a Signal
Lecture 53 - Fourier Series
Lecture 54 - Fourier Series (cont.)
Fourier Transform, DFT and FFT
Lecture 55 - Fourier Transform
Lecture 56 - Fourier Transform (cont.)
Lecture 57 - Fourier Transform (cont.)
Lecture 58 - Discrete Fourier Transform (DFT)
Lecture 59 - Discrete Fourier Transform (cont.)
Lecture 60 - Discrete Fourier Transform (cont.)
Weighting and Loudness
Lecture 61 - Measuring Sound Signals
Lecture 62 - Microphones
Lecture 63 - Classification of Microphones based on Application
Lecture 64 - Weighting
Lecture 65 - Loudness
Lecture 66 - Loudness (cont.)
Miscellaneous Topics and Closure
Lecture 67 - Octave Band Analysis, Part I
Lecture 68 - Octave Band Analysis, Part II
Lecture 69 - Octave Band Analysis: Plotting Octave Band Plots
Lecture 70 - Reverberation Time
Lecture 71 - Calculation of Reverberation Time and Sound Transmission Class (STC)
Lecture 72 - Noise Reduction Coefficient (NRC)