Definition
Psychophysical acoustics deals with the relationship between the physical parameters of sound (frequency, wavelength, intensity, pressure) and their subjective perception by humans (loudness, pitch, timbre).
Psychophysical Parameters
- Objective (Physical) Characteristics:
- Frequency (f): Number of oscillations per second (Hz). Determines pitch.
- Wavelength (λ): Distance a wave travels during one oscillation (λ = v/f).
- Intensity (I): Energy per unit area per unit time (W/m²).
- Sound Pressure (P): Root mean square variation in pressure due to the sound wave.
- Subjective (Perceptual) Characteristics:
- Sound Level (Loudness): Perceived magnitude of sound, measured in decibels (dB).
- Pitch: Human perception of frequency.
- Timbre: Quality or color of sound that distinguishes sources with the same pitch and loudness (e.g., violin vs. flute).
Types of Sound
- Tones:
- Simple: One frequency.
- Complex: Combination of multiple harmonics.
- Acoustic Resistance (Za) = ρ × c (density × velocity of sound).
- Noises: Irregular sound waves with broad frequency spectrum.
- Intensity I = (P_{max}^2) / Z_a.
- Sonic Booms: Produced when an object moves faster than sound; wavelength λ = c/f.