Spek is described as 'helps to analyse your audio files by showing their spectrogram. Spek is free software available for Unix, Windows and Mac OS X' and is an app in the Audio & Music category. There are more than 10 alternatives to Spek for a variety of platforms, including Windows, Mac, Linux, Online / Web-based and Android. The best alternative is Audacity, which is both free and Open Source. Other great apps like Spek are Ocenaudio (Free), Adobe Audition (Paid), Lossless Audio Checker (Free) and Fakin' The Funk? (Freemium).
sndpeek is just what it sounds (and looks) like: - real-time 3D animated display/playback - can use mic-input or wav/aiff/snd/raw/mat file (with playback) - time-domain waveform - FFT magnitude spectrum - 3D waterfall plot
Aspect helps you to analyze your local audio files by building their spectrogram. Spectrogram will show the differences in the frequency range when lossless encoding an audio signal and when lossy encoding.