Flexible loudspeakers that can be easily distributed in the surrounding environment are essential for creating immersive experiences in human-machine interactions, as these devices can transmit acoustic information conveniently. In this paper, we present a flexible electret loudspeaker that offers numerous benefits, such as eco-friendly, easy fabrication, flexible customization, strong durability, and excellent outputs. The output sound pressure level (SPL) and frequency response characteristic are optimized according to the simulation and experiment results. At a distance of 50 meters, a large-size loudspeaker (50 × 40 cm²) can produce an average SPL of 60 dB (normal SPL range of human voices is between 40 to 70 dB). The frequency response of our loudspeaker is high and relatively consistent up to 15 kHz, which covers the normal frequency range of human voices (<8 kHz). As demonstrated in this work, our loudspeakers can be used for scalable applications, such as being integrated with curtains or hung up like posters, offering a promising and practical solution for creating better human-machine interaction experiences.