in 1992, heil and his team pioneered the field of modern line source array loudspeakers with their v-dosc system, which benefitted from l-acoustics’ new wavefront sculpture technology (wst) theory. based on principles developed by heil and fellow physics colleague professor marcel urban, wst defined five criteria for design and use of true line source arrays. at the heart of wst is the internationally-patented dosc waveguide, which was the first high-frequency device capable of creating a rectangular, constant-phase planar output.