10.09.2009 08:21 AM
Originally featured on BroadcastEngineering.com
Schwartz Engineering brings laser microphone technology to AES
Technology touted as a major step in the technological evolution of the microphone was demonstrated at the 127th Audio Engineering Society Show in New York. Laser-Accurate technology from Schwartz Engineering and Design (SED) replaces the conventional microphone with a laminar stream of air in a chamber in which microscopic particles are suspended. When excited by changes in air pressure, the movement of these particles is detected by a laser beam that continuously passes through the chamber aimed at a photoelectric cell on the opposite side.
Engineered and patented by SED as the particulate flow detection microphone, Laser-Accurate will produce precise transduction of any sound without the mechanical motion required by a traditional diaphragm. The company is making its technology available for licensing to manufacturers.
In conventional microphones, the speed with which a diaphragm can react is innately limited by its physical size and shape, and the variety of those mechanical elements inevitably adds tonal coloration to the sound. In the design of Laser-Accurate, the diaphragm or plate is replaced with microscopic particles dispersed in a gas-filled chamber in which the laminar flow of the gas is constant. Detection of the displacement of the airstream and particles by a laser and optical receiver creates a completely non-intrusive method by which to measure the movement of air. This arrangement means no significant mass stands between the source of the sound and its transduction.
An entire professional audio culture has been built upon the colorations that various microphones bring to music. Laser-Accurate does not threaten that culture in any way; rather, in addition to providing an absolutely pristine transduction process, it also acts as the ultimate standard by which all microphones can be evaluated.
David Schwartz, developer of Laser-Accurate technology, is holder of six critical digital audio patents, including one that is the basis for the MP3 file format, and is himself an audiophile. “The color that certain microphones bring can be fantastic,” he says. “The problem is you can’t have all of them, all of the time, meaning that all music recording is a compromise of some sort. With Laser-Accurate technology, all the tonal processing would take place after the sound is converted to a voltage, not during the act of recording it.”
A better signal offers a new world of possibilities, including the potential to create plug-in-style, chip-based processors that mimic the characteristics of classic microphones and preamps, much as modeling guitar amplifiers routinely do now.