NEW YORK — When Angel Reyes helped a friend record his first rap song using a microphone in a cardboard Timberland shoebox, he was just having fun. “We just were in here playing beats,” he recalled. “Like, it was just natural.” With a computer and some software, he taught himself to set vocals to background drums, touching up the sound effects electronically. “I didn’t go to school, nothing. Me and my friends, we just teach each other. Each one, teach one,” Reyes explained. Five years later, Reyes, 28, is a skilled musical engineer at the center of drill rap: the viral and controversial musica…
