Just to clarify for all, each service has its bands. Depending on the specific branch, these may be at the regiment, brigade, division, or corps level. Some are traveling bands, some are bands stationed to a particular post or unit, or ship for that matter.
"The Presidents Own", while a Marine Band, is unique in the true non-military mission it performs. All other service bands, including other performing organizations within the Marines are comprised of active duty service military personnel with the standard duties and obligations associated with that profession.
It is important that anyone contemplating this as a career option be fully aware of the distinction.