Could there be two broad categories of tweak? One which reveals something new in the sound/music which you have never noticed before, and one which increases pleasure but does not necessarily reveal anything new or previously un-noticed. I don't think the PWB free tweaks revealed anything new to me about the recording, even though I was enjoying the listening experience more than usual. A more traditional tweak usually jumps right out and hits you with something you never heard before. The resulting stimulus is not necessarily pleasure, it could be excitement, interest or anticipation.
As for sound and pleasure being equivalent enough to use interchangeably, I think that may be a stretch. I could probably judge the sound (quality) of a system using source material which gave me no pleasure at all. Such as a dog vomiting, if it was really well recorded.
As for sound and pleasure being equivalent enough to use interchangeably, I think that may be a stretch. I could probably judge the sound (quality) of a system using source material which gave me no pleasure at all. Such as a dog vomiting, if it was really well recorded.