Learning Path: "Voice and Sound Recognition"

Chapter 1: SOUND AND WAVEFORMS

The concept that I learnt from this content is fundamental concepts related to sound and waveforms. Sound is described as vibrations produced by objects that cause air molecules to oscillate, creating waves. Mechanical waves, which include sound waves, require a medium to propagate, often air. A sound wave's structure is explained, with areas of compression and rarefaction leading to variations in air pressure, visualized using a pressure plot.

Waveforms, graphical representations of air pressure changes over time, are discussed. Complex sounds are depicted using waveforms, enabling visualization of musical elements like notes and durations. Sound is categorized into periodic (repeating patterns) and aperiodic (non-repeating) types. Periodic sounds include single sine waves, while complex sounds result from the combination of multiple sine waves.

Sound:

● Produced by vibration of an object

● Vibrations cause air molecules to oscillate

● Change in air pressure creates a wave

Mechanical wave:

● Oscillation that travels through space

● Energy travels from one point to another

● The medium is deformed?

WaveForm:

?Carries multifactorial information:

○ Frequency

○ Intensity

○ Timbre

The parameters of a sine wave are explained amplitude (perturbation height), frequency (cycles per second), and phase (position at time zero). Frequency and amplitude impact sound perception, with higher frequency and amplitude resulting in higher perceived sound and louder volume. The concept of pitch is introduced, highlighting its logarithmic perception.MIDI notes, a convention for representing musical notes, are explained in the context of a piano keyboard.The higher the frequency ,the higher the sound wave is.Mapping Pitch of Frequency is derived with formula of

F(P) = 2^(p-69/12)*440

Hearnig Capacity:

Chapter 2: Intensity,Loudness and Timbre

Sound Power:

It is a physical method to measure the range of sound.Rate at which energy is transferred .Energy per unit time emitted by a sound source in all directions .Measured in watt(W).

Sound Intensity: Sound power per unit area and mesured in W/m^2

Threshold of hearing:Humans can perceive sounds with small intensities?

TOH?= 10^-12 W/m^2

intensity Level: To describe the intensity of sound and the range is large so why we measure in Lograthmic scale and measured in decibels (dB) and the ratio between two intensity values.Use an intensity of reference (TOH)

db(I) = 10*logbase10(I/IbaseTOH)

Complex Sounds:Superposition of sounds .A partial is a sinusoid used to describe a sound.The lowest partial is called fundamental frequency.A harmonic partial is a frequency that's a multiple of the fundamental frequency.

Timbre recap:

1. Multifactorial sound dimension?
2. Amplitude envelope?
3. Distribution of energy across partials
4. Signal modulation(frequency/amplitude)