This hourglass shape, though invisible to the naked eye, helps to appropriate the pitch/scale discrepancy among the chalumeau and clarion registers ideal 12th. The diameter of the bore impacts elements comparable to available harmonics, timbre, and pitch stability how far the player can bend a note in the fashion required in jazz and other music. The bell at the underside of the clarinet flares out to boost the tone and tuning of the lowest notes. The fixed reed and reasonably uniform diameter of the clarinet give the device an acoustical behavior approximating
that of a cylindrical stopped pipe. Recorders use a tapered inner bore to overblow at the octave when the thumb/sign in hole is pinched open, while
the clarinet, with its cylindrical bore, overblows at the 12th. Adjusting the point of view of the bore taper controls the frequencies of the overblown notes harmonics.