Editing Recorder (musical instrument) (section)

==== Air ====
As in organ [[flue pipe]]s, the sounding pitch of duct type whistles is affected by the velocity of the air stream as it impinges upon the labium. The pitch generally increases with velocity of the airstream, up to a point.<ref>{{Cite web|title = Pipe sensitivity|url = http://www.fonema.se/pipstiff/pipstiff.html|website = www.fonema.se|access-date = 11 February 2016}}</ref>

Air speed can also be used to influence the number of pressure nodes in a process called over blowing. At higher airstream velocities, lower modes of vibration of the air column become unstable, resulting in a change of register.

The air stream is affected by the shaping of the surfaces in the head of the recorder (the "voicing"), and the way the player blows air into the windway. Recorder voicing is determined by physical parameters such as the proportions and curvature of the windway along both the longitudinal and latitudinal axes, the bevelled edges (''chamfers'') of the windway facing towards the labium, the length of the window, the sharpness of the labium (i.e. the steepness of the ramp) among other parameters. The player is able to control the speed and turbulence of the airstream using the diaphragm and vocal tract.