A range of highly-optimised electro-dynamic audio transducers from Tectonic Elements that can be used to turn flat surfaces into effective high quality loudspeakers. With a wide range of sizes and styles, and power ratings up to 30W, these versatile moving-coil exciters are suitable for a diverse range of both indoor and outdoor applications including modes of transport, consumer electronics, and industrial type products. Excellent sound radiators can be produced using a variety of rigid materials including paper honeycomb and foam board and plastics. These compact devices offer space and weight savings, and can be used to create robust, ’invisible’ loudspeakers that deliver full range audio with wide sound dispersion.