acoustic spectrum analyser

 Spek helps to analyse your audio files by showing their spectrogram.
 It supports all popular lossy and lossless audio file formats.
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 Features:
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  * Ultra-fast signal processing, uses multiple threads to further
    speed up the analysis
  * Shows the codec name and the audio signal parameters
  * Can save 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