Interesting to see folks working with these ideas. As with other terms, "subjective" and "objective" are words which do different work depending on context.
If I say, "These speakers sound good to me, subjectively" that is an objective statement about my sensory experience. It's a way of saying that I don't think I'm in an illusion about my experience, but that it's really happening to me. There might be ways of proving that to others -- with a brain scan, for example (someday) -- but you could also take my testimony as evidence, too. When a patient tells a doctor, "I'm in pain" that is taken as objective evidence by the doctor of the existence of pain, right?
If I say, "These speakers sound good, objectively" that is an objective statement about the kind of sensory experience others could be predicted to have. It's a hypothesis. It needs to be tested by others who are capable of having sensory experiences like mine. I could not ask my refrigerator to have this experience, because it's not capable.
What's the difference, then, between saying "These speakers sound good to me, subjectively" and saying, "These speakers sound good, objectively"?
The difference is merely one of confidence about my prediction. The first indicates that I am too uncertain about my experience to predict that others will have it. The second indicates a higher confidence that others will hear what I'm hearing.
That's really all I see at stake in these words.