"Church Call" is a

bugle call A bugle call is a short tune, originating as a military signal announcing scheduled and certain non-scheduled events on a military installation, battlefield, or ship. Historically, bugles, drums, and other loud musical instruments were used fo ...

which signals that religious services are about to begin. The call may also be used to announce the formation of a funeral escort. \header \paper \score

References

Bugle calls {{music-instrument-stub