Spek helps to analyze your audio files by showing their spectrogram.

Features:

Supports all popular lossy and lossless audio file formats thanks to the FFmpeg libraries.
Ultra-fast signal processing uses multiple threads to further speed up the analysis.
Shows the codec name and the audio signal parameters.
Allows saving the spectrogram as an image file.
Drag-and-drop support; associates with common audio file formats.
Auto-fitting time, frequency and spectral density rulers.
Adjustable spectral density range.
Translated into 19 languages.