Cup depth, mouthpiece

For hemispherical and sharp-edged cup shapes, the cup depth of a mouthpiece is the distance along the axis from the plane of the furthermost part of the rim contour to the edge of the bottom of the cup; for cuspoidal and conical cup shapes, the cup depth is the distance along the axis from the plane of the furthermost part of the rim contour to the point of minimum bore; for funnel and intermediate cup shapes, the cup depth is the distance along the axis from the plane of the furthermost part of the rim contour to the point of maximum curvature of the bore profile (point of maximum throat curvature). In the case of `double-cupped' and other unconventional mouthpieces, individual description id required