the effect has to be how the brain processes the information... my college days are a bit faded by now, but from what i recall, something in the plant allows the brain to process a much higher bandwith of sound, so to speak... details leap out, like comparing a live symphonic concert to a cassette tape... the sound just comes alive.
play a little guitar myself, so, it was really noticeable for me... certain albums or music really brings out the effect... the some old 1960's pink floyd (umaguma- the live tracks- astronamie domanie, or hendrix, 'are you experienced')...