NPL has developed a non-invasive method to visualise sound propagation and help sound engineers design out dead spots in loudspeakers. A new laser-driven technique developed at NPL to allow remote and rapid mapping of sound fields. Particularly useful for looking at speaker directivity characteristics. Measurements made at a distance of 3m from speaker.
HIFI loudspeakers can be designed to deliver the full frequency range of audible sound, but it is difficult to achieve a smooth frequency output in all directions. Dead spots are caused by deconstructive interference, as a result of sound waves overlapping and cancelling each other out. This creates areas where the frequency response of the loudspeaker is less smooth, and sound quality is diminished.