The chamfer/rounding at the end of the windway that opens on the mouth/voicing is responsible for the quality of articulation of the ducted flue instrument. It consists of one or both of the windway exit lips being rounded. This can be seen by looking through the labium (window) at the place where the windway opens out on the mouth/window. These rounded edges affect the responsiveness (tonguings) produced by the player. This enables the rhythmic and dynamic language of the instrument to be "spoken". Articulations such as "Ta", "Da", "Ra", "Ta-ka" and "Da-ga" and "Diddle" will be very clearly differentiated in a good instrument played by a good player. An inferior instrument lacking these modified rounded edges on the windway exit will greatly limit the dynamics of tone or create "dead spots" in the music. The lack of this feature will degrade the performance of a ducted flue instrument, regardless of the effort made by the player to correct tone, or his or her level of skill.