Many software programs provide the incorrect bit rate of audio files. For example, iTunes will display the current bit rate of a file, but the file may have been previously compressed down to a much lower value. This misleading process is known as upscaling.
Enter Spek
Spek helps analyze your audio files by showing their true spectrogram. Spek is free software available for Unix, Windows and Mac OS X. Essentially, bit rates work with frequency – higher bit rates preserve higher frequencies. For example, 320kbps cuts off at 20kHz, as shown below.
So the next time you have a new MP3 file with an allegedly high bit rate, drop it into Spek for the true test. The program is light-weight, fast, and non-invasive – a must-have for DJs and music fans.