I'm an audiophile, and I can tell you from looking at the FFT which settings you used in LAME to make that MP3* :) Different presets set different lowpass filt

I'm an audiophile, and I can tell you from looking at the FFT which settings you used in LAME to make that MP3* :) Different presets set different lowpass filter values, opting for the best balance between preserving frequencies, achieving a small file size, and the perceived quality. The latter is often measured with various approximations to human perception of sound - psychoacoustics. This is why you can't compare different encoders using an approximation - the algorithms themselves are made using them. It's the Dunning-Kruger effect, but for computers. You can actually change those presets, so you can hear for yourself what effects changing it has: http://lame.cvs.sourceforge.net/viewvc/lame/lame/USAGE http://lame.cvs.sourceforge.net/viewvc/lame/lame/USAGE * Why would anyone bother to learn this skill? Well, I don't mind MP3s (or AACs or OGGs for that matter), and I certainly can't tell the difference between them and lossless formats, but an MP3 that has been re-encoded several times is really atrocious. It's like when you re-compress a jpg a few times, it gets messy. This helps definitively figure out what an MP3 really is or was. Sometimes the tags on the MP3 lie about which encoder was used or what the compression settings were. Other times, the file used to be something else, such as re-encoding a 128kbps MP3 as a LAME V0 preset MP3. Looking at the frequency plot in a sound editor makes this rather obvious, as the lower presets and crummier encoders have much lower lowpass filters.