Basics of Acoustics

1. Introduction

Sound is produced by vibrating objects and travels through a medium as a wave. Acoustics studies how sound is created, transmitted, and heard by humans.

• Science of sound
• Important for audio engineering

2. Sound Waves

Sound waves are mechanical waves that require a medium such as air, water, or solids to travel.

• Longitudinal waves
• Consist of compressions and rarefactions

3. Frequency

Frequency is the number of vibrations per second and is measured in Hertz (Hz).

• Determines pitch
• Higher frequency → higher pitch

4. Amplitude

Amplitude represents the strength or intensity of a sound wave.

• Determines loudness
• Measured in decibels (dB)

5. Wavelength

Wavelength is the distance between two consecutive compressions or rarefactions.

• Inversely proportional to frequency
• Affects sound propagation

6. Speed of Sound

The speed of sound depends on the medium through which it travels.

• Faster in solids than gases
• ~343 m/s in air at room temperature

7. Audible Range

Humans can hear sounds within a specific frequency range.

• 20 Hz to 20,000 Hz
• Below: infrasonic, Above: ultrasonic

8. Sound Reflection and Absorption

When sound waves hit a surface, they may be reflected, absorbed, or transmitted.

• Reflection causes echo
• Absorption reduces noise

9. Importance of Acoustics

• Improves sound quality
• Used in studio and hall design
• Essential for multimedia systems

10. Applications

• Audio recording studios
• Concert halls and theaters
• Noise control engineering
• Multimedia production

Practice Questions

1. What is acoustics?
2. Define frequency and amplitude.
3. What is the audible range of humans?
4. Explain sound reflection.
5. Why is acoustics important in multimedia?

Practice Task