Acoustic phantom

Professional Definition

The acoustic spectrum is a representation of the amplitude values describing acoustic vibrations as a function of frequency.

In engineering practice, the spectrum is most often obtained through Fourier analysis (e.g., FFT). The spectral graph on the horizontal axis (X) presents the frequency (in Hertz), while the vertical axis (Y) represents the amplitude, usually expressed in decibels (dB). This allows for the assessment of sound color and identification of frequency dominance in industrial or environmental noise.

Acoustics in Simple Terms

The acoustic spectrum acts like a prism for sound. When white light enters a prism, it disperses into a rainbow of colors. Similarly, spectral analysis takes “gray” noise and shows how much “red” (low bass), “green” (mid tones), and “purple” (high pitches) it contains. This way, the acoustician knows whether to use thick concrete (for bass) or light foam (for high tones) to silence a machine.

Summary

The acoustic spectrum is a graphical “fingerprint” of sound, showing its frequency composition. It is an essential tool in choosing insulation and correcting room acoustics.