|Inventor with early prototype
Bo Bengtsson, well-known Swedish sound designer and former consultant to several high-end US speaker manufacturers, has been investigating the subject of hearing damage relative to speakers. In conjunction with NJ-based Transmission Audio Inc and Sweden-based Transmission Audio Scandinavia, Bengtsson appears to be the first in the world to deal successfully with the issue of hearing impairment caused by high sound pressure levels from loudspeakers in public and domestic environments. In addition to its ability to reduce the risk for hearing damage, this technology also elevates the standards for sound reproduction, just as HDTV raised the bar for video reproduction.
The audio industry has expended a lot of time and energy creating speakers for domestic and public address use that can play very loud. As a result, increasingly greater numbers of people are suffering from hearing impairment caused by exposure to high sound pressure levels from speakers with uneven frequency response and high distortion.
According to published reports, hearing damage caused by exposure to overly loud (and distorted) sound is increasing annually. As an example, former President Bill Clinton now wears 2 hearing aids, which he readily admits are necessary to compensate for hearing loss sustained while he was exposed to loud music through the years.This has become an environmental health problem similar to the issue of passive smoking. It is particularly problematic in restaurants and clubs, where one often finds tools like the deciBell meter bypassed "to suit customers' desired level" as many owners state.
What causes the problem?
- Uneven sound levels; i.e.,the sound gets louder the closer you are to the speaker, known as the point source effect.
- Uneven disperson of different frequencies within the sound spectrum caused by non-linear transducers and/or complex crossover filters.
- Inherent distortion in the speakers themselves.
- Uneven frequency characteristics in the listening environment.
A new technology is born
The Dynamic/Ultra PropulsionTM technology is part of the solution to this problem. A new type of ribbon-based sound transmitter utilizes a combination of 1-inch and 2-inch-wide ribbons, suspended at their ends only and mounted in an extremely strong magnetic field. The technology is patent-applied-for and pending.The system is built up from modules, making it easy to adjust the ribbons to different environments for optimum evenness in dispersion as a function of different room characteristics.
By combining and refining this rarely used but well known transducer technology, and by arranging a multitude of these elements in a line source configuration, the emitted sound is evenly spread throughout the listening area.
Ribbons as well as line source columns have been used before in audio history, but not like this: The Dynamic/Ultra PropulsionTM technology is absolutely unique in that the ribbons are true ribbons, suspended only at the top and bottom, thereby avoiding any buildup of unwanted energy storage. In addition, the elimination of any type of "carrier" (usually a plastic film bonded to the ribbon) decreases mass and prevents energy absorbtion and/or energy storage, thereby reducing all types of audible distortion/cross modulation to extremely low levels.
Ultimately, what makes Transmission Audio's technology stand out from the rest is the completely new interface between the ribbons and the amplifier driving them. This new interface allows the ribbons to behave as a "straight wire with gain" and makes it possible to use a single ribbon from 40kHz down to 200Hz without any crossover network in between.
The research and development behind the Dynamic/Ultra Propulsion technology took a little more than a decade to fine tune. As a result, the ribbons ability to deal with high power is extraordinary. It might be worth mentioning that as opposed to regular ribbons, the MF ribbons can handle membrane excursions in excess of plus minus 6 millimeter whilst the MF/treble ribbons can move freely within plus minus 3 mm.