A singer gives you somewhere obvious to look. A trumpet does, too. The bass player may be doing less to catch your eye while quietly deciding how the whole performance moves.
Try following only the bass for a verse. Listen for the notes that arrive with the drummer and the ones that lean away. Notice whether the line repeats faithfully or changes its route under the same chords. You do not need the names of those chords to hear the difference between a settled foundation and a restless one.
Outdoors, this can take patience. Traffic and conversation compete for attention, and where you stand affects what reaches you. Move only where there is room, without stepping into the performance area. Sometimes a modest change of position reveals a part that seemed absent.
Once you have found it, return to the whole band. A clipped guitar phrase may now sound like an answer to the bass. The singer's pause may feel supported rather than empty. Parts you heard as separate begin to share a common motion.
There is no prize for listening correctly. This is simply a way to refresh a familiar situation. The next time a street band makes you stop, you might find yourself watching the least conspicuous musician first, waiting to hear where the song is going to put its feet.
