Coding/Sound
Ch2. Intensity, Loudness, and Timbre
linguana
2021. 3. 30. 10:19
Sound power: rate at which energy is transferred (watt; W)
Sound intensity: sound power per unit area (W/m^2)
1 Watt = Thunder = Orchestra (a bulb is 100 W)
Threshold of hearing (TOH): Human can perceive sounds with very small intensities (10^-12 W/m^2)
Threshold of pain (TOP): too intense to hear (10 * W/m^2)
Intensity level
- Logarithmic scale
- Measured in decibels (dB) dB(I) = 10 * log(I /I of TOH)
- What is 0 dB?
- The point when “log(1) = 0” is met
- Every 20 dB, intensity doubles
- Ration between two intensity values
- Use an intensity of reference (TOH)
Loudness
- Subjective perception of sound intensity
- Depends on duration / frequency of a sound
- Depends on age
- Measured in phons
