The speaker is mostly hidden from us – there is no "me" or "I" mentioned. But he tends to pop out from behind his veil of objectivity with this habit of telling us his emotions. He’s like, "Here I am! And I feel sad!" He says that the scale of dissolution is "awful" and its music is "melancholy." What he really means is that change frightens him, and he doesn’t like to see the things he loves pass away.
But otherwise he does a good job at hiding himself from us. He uses big words and grand diction that are more formal than intimate. You could even call him haughty. At least some of the second-generation Romantic poets like Percy Shelley and Lord Byron might have agreed with you there. You’d almost think the speaker was auditioning for some stuffy period drama on the BBC. (OK, we admit: we love those dramas, and heck, we love Wordsworth too.) And, as with so many English poets, you can tell the speaker has read a lot of Shakespeare.
The speaker likes to take the long view of his life and of history. While others are worried about the day-to-day, he has come to realize that things change so quickly that no situation, good or bad, will last. You might as well embrace mutability, he thinks. Further, he wants us to believe that his ability to hear the music of change means he is a respectable person. He says that people who get caught up in crime and greed can’t hear the music, and he clearly can, so he must not have "meddled" in these things. So there you have it: he wins the "Upstanding Citizen Award."