From Hydrogenaudio Knowledgebase
- Why Shouldn't We Use Frequency or Spectral Graphs to Compare Audio Codecs?
- You can't know precisely what is audible and what is not audible just by looking graphs.
- FFT frequency response graphs are rough and can't tell practically anything about the temporal (short time) accuracy.
- All psychoacoustic models are different. What can look good in graphs, doesn't necessarely sound too good and vice versa.
- Graphical analysis is often useful, but only when used together with listening testing. The most useful view is the sound spectra view (spectral view in Adobe Audition).
- Blind listening testing (ABX) is the only method that can really be justified when testing quality. Blind testing, when enough propability is reached, is not affected by anykind of bias or placebo.
- Difference/substraction/inverse-mixing method is not conlusive either
