Hardware solutions for industrial voice recognition (headset, microphone)

What hardware solution to implement voice in my company?

The implementation of voice, intelligent voice assistance, or a conversational agent in a company requires the use of suitable audio equipment. The selection of this material (headset, microphone) and the connection technology requires special expertise.

Several factors must be considered in order to make the right choice:

  • Use and acceptance by operators, equipment already worn, safety constraints,
  • The industrial environment: noise, frequency plans, mobility and proximity to operators,
  • The desired voice recognition performance based on budget, robustness, use,
  • Integration into the environment of Information Systems and industrial processes in place.

SPIX industry has the expertise, methods and tools needed to help manufacturers in their choices.

Reference document…

voice and speech

The voice is a sound wave, a sound produced orally, thanks to the biological organs of the human body. The respiratory system supplies air which enters the larynx. The vocal cords located in the larynx then emit vibrations which are then transformed into sounds in the vocal tract. The displacement of the larynx from bottom to top makes it possible to act on the frequency of the sounds produced, to have more acute or more serious sounds. The oral and nasal cavities, the position of the tongue, the jaw, the lips and the teeth also act on the modulation of the wave, as resonators.

Speech corresponds to all the sounds used in the voice by human language. The frequency of the fundamentals used by speech is between 300 Hz and 1200 Hz. The frequency band of the fundamental waves of speech depends on the age and sex of the person: approximately 70 to 250 Hz in men, 150 to 400 Hz in women, and 200 to 600 Hz in children . But, considering the harmonics, the speech frequency band can extend from 40 Hz to 10,000 or even 15,000 Hertz.

However, for good audibility and good speech understanding between two humans, the necessary band can be reduced to a narrow band of 300 to 3400 Hz, a standard long used in telephony. A widened band can be considered from 50 to 8000 Hz.

As a result, the captured voice frequency band will therefore have an impact on voice recognition and its proper transcription of speech. The ability of the audio equipment and the subsequent signal transmission and processing chain to maintain the maximum frequency band is therefore an important criterion in the selection.

The noise

From a wave point of view, noise is a wave identical to the wave of the voice. The difference concerns the harmonics. The frequency of the harmonics of the voice is linked to the frequency of the fundamental (which makes it pleasant), which is not always the case for noise…

Like any sound wave, the important characteristics that define a noise are its frequency and its intensity.

In accordance with the law, it may be advisable or even mandatory to wear hearing protection in your factories or installations. The duration of exposure to noise is a factor independent of the wave but an essential factor from a regulatory and legal point of view for the need or not to wear hearing protection ( directive 2003/10/EC ).

Depending on the industrial noise environment, operators are required to wear hearing protection equipment (PPE). The selection of audio equipment must take these PPE into consideration in order to offer compatible equipment for the safety of operators.

Test and validate

SPIX industry has invested in a deaf room in order to carry out tests and validate audio devices.

Several test cases are possible depending on the availability and feasibility, or not, of sound recording in the target industrial environment:

  • VOICE+NOISE sound recording in the target environment
  • Sound recording NOISE in the target environment
  • Very high quality noise sound library

The performance of audio tests and the validation of particular equipment relies on the particular expertise of SPIX industry. This expertise is made available to manufacturers during the material studies carried out for the implementation of voice solutions in the company.

The right questions to ask

Work status

The definition of the workstation of the operator concerned by the use of the voice greatly influences the adapted hardware device. If the operator is “at a fixed position” (production, edge of line, assembly, etc.) or in “mobility” (maintenance, inspection, industrial logistics), the appropriate technologies will not be the same.

Finally, for outdoor operations, additional constraints apply, related to wind and rain.

The noise level

Analysis of the average surrounding sound level makes it possible to select appropriate audio equipment. All operators are not necessarily equipped with the same equipment, depending on the noise level, but also on their work situation.

Protective equipment

Operators who already wear protective equipment must have voice use compatible with their safety. Depending on the existing PPE, audio solutions exist that provide comfort and guarantee safety.

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