Final answer:
Bubber Miley was the soloist who enriched Duke Ellington's early recordings with unusual timbres through his mastery of mutes.
Step-by-step explanation:
The soloist who enriched Duke Ellington's early recordings with unusual timbres arising from his mastery of mutes was Bubber Miley. Miley was a prominent jazz trumpeter known for his innovative use of mutes to create unique sounds. His contributions to Duke Ellington's music added depth and distinctive qualities to the recordings.
Learn more about Bubber Miley's contribution to Duke Ellington's early recordings