Strikingly, pitchers at singing conventions generally do not use any mechanical aid, such as a pitch pipe or tuning fork, to help them find the right pitch. (Such aids may be more common at small local singings.)
How Sacred Harp pitchers (who generally do not possess perfect pitch) achieve their ends without mechanical help is not a fully understood question. It probably helps that pitchers typically know the songs very well, and that they have the opportunity to test out how a particular key “feels” when they sing the first note aloud. Sometimes a pitcher will try one opening note, find it unsatisfactory, then execute a glissando to a neighboring pitch.
Cobb lists some ways in which pitchers make up for the lack of a pitch-giving device. Some use their own voices as a kind of reference, for instance by knowing the lowest note they can comfortably sing. Others have a kind of “reference song”; a song so familiar that when they summon it to mind it is in the original key, which then can be used as a reference point. For many singers, however, good pitching seems to be a purely intuitive activity, a skill they possess but cannot explain. One experienced pitcher told Cobb “it’s kind of like learning to fix an automobile–you just got to have a knack for it.”