Analysis of Introduction to an Album

I am a harp of many chords, and each
Strung by a separate hand;—most musical
My notes, discoursing with the mental sense,
Not the outward ear. Try them, they will reply
With wisdom, fancy, graceful gaiety,
Or ready wit, or happy sentiment.
Come, add a string to my assort of sounds;
Widen the compass of my harmony;
And join thyself in fellowship of name
With those, whose courteous labour and fair gifts
Have given me voice, and made me what I am.