Gestural instruments can be divided into two categories based on the type of the reference frame used by the controller. An egocentric controller uses a reference frame that is centered on and follows a point of the performer's body to measure the body point positions relative to some other body points. An allocentric controller uses a stationary reference frame attached to an object other than the performer's body. The allocentric option is the more commonly used by gestural instrument designers. The egocentric option has been used and explored less frequently. This paper studies, at a low level and high level: 1- The similarities and differences between egocentric and allocentric controllers for gestural instruments from the perspective of performer and instrument designer. 2- The affordances and constraints of egocentric and allocentric controllers as they, to a large degree, define the characteristics of an instrument. The paper presents the initial results of a subjective experiment to encourage the future discussion and study of the subject.