An audio spectrogram is a visual representation of a sound. In other words, it is an extremely intricate audio analyzer. As a result, it provides a very detailed and accurate image of audio. A spectrogram is a time-varying spectral representation that has a wide diversity of spectral density of any given signal with respect to time. Spectrograms, sonograms, voicegrams, and spectral waterfalls recognize phonetic sounds, so they are common in tasks such as speech processing.
Spectrograms: the Physics
Experts develop spectrograms by using a series of bandpass filters to create the estimated filter bank and Short-Time Fourier Transform (STFT) calculated from the time signal. It is common to use STFT to obtain an audio spectrogram. To be able to calculate the STFT of a signal, it’s vital to process the input audio signal. Once you calculate the STFT, you must transform the signal and make it suitable for a video monitor display.
Sound engineers tend to use audio spectrograms frequently for the sound restoration process. To attain successful audio restoration, they must be capable of analyzing the whole context. By offering a visual representation of an audio sound, spectrogram technology makes the process quite simple. To be able to make adequate editing decisions, every visualization tool for audio repair and restoration must offer the user complete information regarding the audio conflict. The spectrogram display offers innovative ways to make the editing process more enjoyable.
Spectrogram: the Audio Image
You can perceive the image resulting from a spectrogram in either 2D or 3D. When this happens, a graph emerges. This graph explains the audio according to time and frequency, as well as brightness and height (in relation to amplitude). It illustrates how every frequency component in a signal can change its amplitude.
Every spectrogram is unique. The Fast-Fourier Transform (FFT) calculates the visual display. And you can modify it. The way the algorithm calculates the spectrogram changes by modifying the FFT. Because of this, many products that involve a spectrogram display allow the user to adjust its size. A higher FFT will offer a more detailed frequency resolution, whereas a lower FFT will provide a more detailed time resolution. The user is able to decide which FFT to use depending on the objective.
