A middle ear transducer arrangement comprising: an implantable transducer for converting an electrical stimulation signal into a corresponding mechanical stimulation signal, the transducer having an elongated shape with a transducer end face having: a transducer drive surface adapted to produce the mechanical stimulation signal; and a coupling cap having: a coupling end face including a coupling drive surface, and a signal delivery surface for delivering the mechanical stimulation signal to an adjacent cochlear surface for sensation as sound; the middle ear transducer arrangement characterized by: the transducer end face having at least one transducer adhesive feature (304; 401) adapted to intra-operatively receive adhesive material during surgery to implant the transducer in a recipient patient; the coupling end face including at least one coupling adhesive feature (306; 402) adapted to engage the at least one transducer adhesive feature and the adhesive material to fixedly connect the coupling cap to the transducer end face; and the coupling drive surface being in direct and adhesive-free contact with the transducer drive surface for distortion-free coupling of the mechanical stimulation signal from the transducer drive surface to the coupling cap. an implantable transducer for converting an electrical stimulation signal into a corresponding mechanical stimulation signal, the transducer having an elongated shape with a transducer end face having: a transducer drive surface adapted to produce the mechanical stimulation signal; and a coupling cap having: a coupling end face including a coupling drive surface, and a signal delivery surface for delivering the mechanical stimulation signal to an adjacent cochlear surface for sensation as sound; a transducer drive surface adapted to produce the mechanical stimulation signal; and a coupling cap having: a coupling end face including a coupling drive surface, and a signal delivery surface for delivering the mechanical stimulation signal to an adjacent cochlear surface for sensation as sound; a coupling end face including a coupling drive surface, and a signal delivery surface for delivering the mechanical stimulation signal to an adjacent cochlear surface for sensation as sound; the middle ear transducer arrangement characterized by: the transducer end face having at least one transducer adhesive feature (304; 401) adapted to intra-operatively receive adhesive material during surgery to implant the transducer in a recipient patient; the coupling end face including at least one coupling adhesive feature (306; 402) adapted to engage the at least one transducer adhesive feature and the adhesive material to fixedly connect the coupling cap to the transducer end face; and the coupling drive surface being in direct and adhesive-free contact with the transducer drive surface for distortion-free coupling of the mechanical stimulation signal from the transducer drive surface to the coupling cap. the transducer end face having at least one transducer adhesive feature (304; 401) adapted to intra-operatively receive adhesive material during surgery to implant the transducer in a recipient patient; the coupling end face including at least one coupling adhesive feature (306; 402) adapted to engage the at least one transducer adhesive feature and the adhesive material to fixedly connect the coupling cap to the transducer end face; and the coupling drive surface being in direct and adhesive-free contact with the transducer drive surface for distortion-free coupling of the mechanical stimulation signal from the transducer drive surface to the coupling cap.