With reference to FIG. 7a the present invention relates to transducer apparatus (200) for use with a reed instrument (201) having an air chamber (15) forming a resonant cavity whose resonance characteristics are controlled by opening and closing of tone holes (17A, 17B) connecting the air chamber to the exterior of the reed instrument. The transducer apparatus comprises attachment means (202) for releasably securing the transducer apparatus to a mouthpiece (201) of the reed instrument in place of a reed. A reed replacement section (203) has a housing with an abutment surface for abutting a surface part of the mouthpiece which would be abutted by a reed secured to the mouthpiece. An air passage extends through the housing of the reed replacement section (203) from an air inlet (211) through which a player of the instrument can blow to an air outlet (213) through which air blown by the player is delivered to atmosphere, without passing through the air chamber (15) within the reed instrument. A speaker (208) is supported by the housing and delivers sound to the air chamber (15). An air chamber microphone (209) is supported by the housing and receives sound in the air chamber (15). An electronic processing unit (204) has: an excitation unit (101) which produces an excitation signal for driving the speaker (208); a processor (102) for receiving a measurement signal produced by the microphone and for detecting from the measurement signal a musical note played by the instrument; a synthesizer (220) for generating an electronic signal embodying a musical note which corresponds to the detected musical note; and output means (103) for transmitting the musical note generated by the synthesizer to a receiver external of the transducer apparatus. The invention also relates to a system for representing the sounds of a reed instrument having the components of the transducer apparatus, to an electronic system for determining a musical note played by a reed instrument having the components of the transducer apparatus and to a method of practising playing of a reed instrument comprising use of the components of the transducer apparatus.