An apparatus for use with a hearing assistance device, the apparatus comprising: a receiver case configured to house a hearing assistance device receiver, the receiver case including a spherical receiver spout (106, 306, 606), the spherical receiver spout (106, 306, 606) including an opening; and a receptacle housing including: a spherical socket (324, 624) adapted to mate with the spherical receiver spout (306, 606) to form a ball and socket connection; and an convex insert within the spherical socket (324, 624), the convex insert is configured to establish a retained interference fit with the opening of the receiver spout (306, 606) when the connection is formed so as to create an acoustic seal therebetween, wherein the opening in the spherical receiver spout (106, 306, 606) has a radially concave contour, and the spherical socket (324, 624) includes a retention feature (334, 634) having an undercut that determines a retention force of the ball and socket connection and the undercut configured to provide for a reduced amount of necessary force to connect the spherical receiver spout (306, 606) and spherical socket (324, 624) whilst retaining a higher amount of necessary force to disconnect the spherical receiver spout (306, 606) and spherical socket (324, 624). a receiver case configured to house a hearing assistance device receiver, the receiver case including a spherical receiver spout (106, 306, 606), the spherical receiver spout (106, 306, 606) including an opening; and a receptacle housing including: a spherical socket (324, 624) adapted to mate with the spherical receiver spout (306, 606) to form a ball and socket connection; and an convex insert within the spherical socket (324, 624), the convex insert is configured to establish a retained interference fit with the opening of the receiver spout (306, 606) when the connection is formed so as to create an acoustic seal therebetween, wherein the opening in the spherical receiver spout (106, 306, 606) has a radially concave contour, and the spherical socket (324, 624) includes a retention feature (334, 634) having an undercut that determines a retention force of the ball and socket connection and the undercut configured to provide for a reduced amount of necessary force to connect the spherical receiver spout (306, 606) and spherical socket (324, 624) whilst retaining a higher amount of necessary force to disconnect the spherical receiver spout (306, 606) and spherical socket (324, 624). a spherical socket (324, 624) adapted to mate with the spherical receiver spout (306, 606) to form a ball and socket connection; and an convex insert within the spherical socket (324, 624), the convex insert is configured to establish a retained interference fit with the opening of the receiver spout (306, 606) when the connection is formed so as to create an acoustic seal therebetween, wherein the opening in the spherical receiver spout (106, 306, 606) has a radially concave contour, and the spherical socket (324, 624) includes a retention feature (334, 634) having an undercut that determines a retention force of the ball and socket connection and the undercut configured to provide for a reduced amount of necessary force to connect the spherical receiver spout (306, 606) and spherical socket (324, 624) whilst retaining a higher amount of necessary force to disconnect the spherical receiver spout (306, 606) and spherical socket (324, 624).