New Approach 2

  • The Audiogram of Familiar Sounds shows the decibel values and central frequency of many common sound sources. For example, a small bird sings at about 5000 to 8000 Hz.

chart

  • Amplification of high audio frequencies, 3500 Hz to 10,000 Hz, requires an increase in amplifier power. For a given constant amplitude of sound, the acoustic energy contained in the sound field varies as the frequency squared. This means that if a sound wave at 2000 Hz requires a certain power level for amplification then a 4000 Hz, which is two times higher frequency will need (2)² = 4 times as much power and a 8000 Hz sound will need (8000/2000)² = 4² = 16 times as much power.
  • Since existing hearing aids are powered by relatively small button type batteries there is simply not enough power available for effective amplification at these high frequencies. Even the use of an incrementally larger battery, in the industry’s new “high power” hearing aids, has not been able to extend the frequency response of the hearing aids by any significant amount. The EarZin uses a significantly higher capacity rechargeable Li-Ion battery for increased power capability. Thus with this increased battery capability the EarZin battery can deliver appreciable more power and hence more amplification and gain than a conventional hearing aid using a relatively small and under powered hearing aid battery. A single battery charge will operate the EarZin for about 48 hours with full usage and has an expected life span of approximately 3 years. Being located in a small housing (with amplifier circuits) the feedback problem is also reduced significantly so that high gain settings can easily be used without feedback squeal annoyances.
  • As seen in the diagram above, normal speech as indicated by the “letter sounds” occurs between about 200Hz to 8000 Hz, and shows that the sibilants, “s”, “th”, and “f” sounds of speech, extend into the higher range of hearing at 3500 Hz to 8000 Hz. Thus it becomes clear why conventional hearing aids do not provide really good speech comprehension since their amplification peaks out at approximately 3200 Hz, and has very limited performance above 3500 Hz.

 

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