Definitions for audibly
Random House Webster's College Dictionary
au•di•bleˈɔ də bəl(adj.)
capable of being heard; loud enough to be heard; actually heard.
(n.)(in football) a change in play called out orally after both teams have assumed their positions at the line of scrimmage.
Origin of audible:
1520–30; < LL audībilis= L audī(re) to hear +-bilis -ble
in an audible manner
"he spoke audibly"
In context of possibility of being heard; in an audible manner.
so as to be heard