DeTune™ Communications Earmuffs

Our second generation of DeTune communications earmuff provides more user control over the noise environment, and their ability to communicate. Users can selectively filter out high and low frequencies in order to improve the understanding of speech in noisy environments.

Elvex DeTune™, Com-640

Elvex DeTune uses a new approach, and allows the user to adjust the frequency range that is transmitted through the circuitry and speakers.

A volume control allows the user to set the sound level inside the headset, up to a maximum of 82 dB
Two control knobs allow the user to filter out the high and the low frequencies independently of each other. When the filters are in the neutral (inactive) position the user will hear the environment almost as if no hearing protector was worn, except for the maximum sound limiter.
The high frequency filter allows an aggressive filtering of the high frequencies, down to about 3,000 Hz. The filter eliminates about 75% of the high frequencies within the adjustment range, and can be considered semi-transparent. If used in an environment dominated by high frequency noise, it can be clearly perceived that the headset filters out a large part of the undesirable noise. The most important speech frequencies are in the range of 500-3.000 Hz., and if we filter out most frequencies above 3,000 Hz., this will obviously also affect the speech perception. Elvex DeTune does however provide a choice to the user in how much filtering is desirable, and allows the user to seek out the filtering level that is optimal for the environment.
The low frequency filter works in a similar fashion, allowing the user to filter out frequencies up to 600 Hz. The effectiveness of the low frequency filter is not as obvious as the high filter, but in certain environments it can clearly help improve the ability to communicate.
DeTune is also equipped with an impact filter. This filter is activated by impact sounds, such as gunfire or rivet operations. The impact filter closes in a few microseconds and reactivates in about half a second.
An automatic gain control maintains an even sound volume, when filtering is applied. Without AGC the volume would decrease when filtering is applied.
Com-640 is equipped with an automatic 4-hour shutoff in order to conserve batteries.
This headset uses two AAA alkaline batteries, and they are accessible from an exterior battery compartment.
An audio jack (3.5 mm) for connection of radios and MP3 players is standard. This jack will provide listen-only capability (not two way communications).
It is important to understand that the electronics in the DeTune hearing protector does not improve the attenuation properties of the passive hearing protector. The electronics simply allow improvement of voice communication and speech understanding, while you continue to protect your hearing.

Attenuation data in accordance with ANSI S12.6-2008,
Dr. Michael & Associates, State College, Pennsylvania, USA

Footnote:

Voice communications in noisy environments has always presented a number of challenges. Workers must wear hearing protectors, and in many cases this adds to their inability to communicate effectively. Standard (passive) hearing protectors attenuate effectively in the high frequencies, and will actually help communications in environments dominated by high frequencies. However, most industrial environments contain a mixture of high, medium and low frequencies, and most users cannot communicate effectively while using passive hearing protectors.

Several generations of electronic hearing protectors have offered more or less effective solutions. Even the active hearing protectors that have been offered have had serious limitations. The computing power has not been available, to read a noise environment and create a negative sound wave, for changing noise environments. The active headsets that have been available have been designed for specific noise environments, such as an airplane cockpit or compressor hall. Active headsets have only been helpful in low frequency noise environments, but the active electronic circuitry has rendered them relatively ineffective against high frequency noise. That is why you have not seen this technology penetrate industrial applications.