Placebo effect

From Hydrogenaudio Knowledgebase

The placebo effect, in the context of digital audio, is a listener's subjective preference/mindset that emotionally influences his/her judgment. E.g. a like/dislike of a compression methodology may cause the listener to rate it better/worse than it actually is.

The only way to banish the placebo effect is by performing a blind listening test, e.g. using the ABX method.