The speaker is really excited to tell his audience about the musician he heard, but he never gets too excited. He's more interested in setting the mood and describing the event, than talking about how much he liked it. He plays it cool – a total hipster. But he's hip in the best sense of the word. He's memorized the lyrics. He acts like you know the tune to "The Weary Blues." His saving grace is that he's not too uptight to drop the image and, for example, shout out "O Blues!" He's also not that guy who can't stay quiet during a slow song.
He also knows the out-of-the-way places to hear great music, and he's cool with hanging out in a shady bar. In turn, the speaker expects his audience to be hip to Lenox Avenue and what sort of place would have this kind of music. He even slips in some interesting wordplay, making it seem like the musician, the music, and the instrument flow in and out each other. The weird thing about the speaker is this: how does he know what the singer felt like as the singer went to bed?