The present invention is directed to musical instruments that are based on the operation of an air reed and, in particular, encompasses end-blown flutes comprising an acoustic air space and a fluid air space. The communication between the acoustic and fluid air spaces is positioned so as to minimally interfere with the flow of air introduced, i.e., blown, into the fluid space and enables the instrument to produce rich, in-tune tones across a three octave range. The acoustic air space is formed by a hollow tuning chamber positioned opposite the air reed. In alternate embodiments, the invention encompasses a head-joint of a musical instrument, which head joint comprises a an acoustic space and a fluid space. The head joint of the invention may be used to replace or in place of the head joint or mouthpiece of common musical instruments of the woodwind family, e.g., the Western flute, saxophone, clarinet, oboe, nay, shakuhachi, or recorder.