In a parametric array, highly directional low-frequency sound is generated by the self-demodulation of an intense, amplitude-modulated high-frequency sound beam as a result of nonlinear propagation effects. Although several examples of using parametric generation by an ultrasonic carrier as an audio loudspeaker have been discussed in the literature, practical constraints have received little attention. In this seminar we discuss an effect of transducer bandwidth that must be overcome in order for the ``audio spotlight'' to become a practical, high-fidelity source for reproduction of music. The importance of transducer bandwidth can be seen by noting that the far-field solution predicts a demodulated secondary waveform along the axis of the beam that is proportional to the second time derivative of the square of the modulation envelope. The secondary wave is therefore generated with high levels of harmonic distortion, even for moderate modulation indices. Integrating the modulation signal twice and taking the square root removes this distortion; however, the resulting reduction in distortion is limited by the bandwidth of the ultrasonic transducer.