Union Army Regulation of July 1861 stated that every company in each branch of the Army designate two men per company as Musicians to contribute to one Brass Band.
Event though this was later disassembled by the Adjutant General a year later in 1862, those men who had been assigned this role continued it for the time of the service or for the extent of the war.
Now available to fulfill your impression.
Comes with a period Two prong PinBack. (Attached with industrial adhesive to not compromise the structure of the badge.)