The human auditory system is most sensitive to frequencies between 2,000 and 5,000 Hz. Individual hearing range varies according to the general condition of a human's ears and nervous system.
The loudness curves all have dips in them between about 2000 and 5000 Hz. These dips mean the ear is most sensitive to frequencies in that range. For example, a 15-dB sound at 4000 Hz has a loudness of 20 phons, the same as a 20-dB sound at 1000 Hz.
Upper limits of hearing, indicating the maximum SPL that the auditory system can tolerate, are also indicated in Figure 2-2. Thus, the dynamic range of hearing covers approximately 130 dB in the frequency region in which the human auditory system is most sensitive (between 500 and 4000 Hz).
Noise above 70 dB over a prolonged period of time may start to damage your hearing. Loud noise above 120 dB can cause immediate harm to your ears.
A wind turbine, a roaring crowd at a football game, a jet engine running full throttle: Each of these things produces sound waves that are well below the frequencies humans can hear. But just because you can't hear the low-frequency components of these sounds doesn't mean they have no effect on your ears.
In general, sounds above 85 dB are considered harmful to human hearing and we should avoid prolonged exposure to them.
7 Hz infrasound (the frequency of the brain and the internal organs) can affect the human central nervous system and cause: general confusion. anxiety and panic. bowel spasms.
A whisper is between 20-30 dB. On the other hand, a human scream can reach decibel levels between 80 and 125 dB.
At 194 dB, the energy in the sound waves starts distorting and they create a complete vacuum between themselves. The sound is no longer moving through the air, but is in fact pushing the air along with it, forming a pressurized wall of moving air.
In fact, the only place in the universe with absolutely no sound is where there is absolutely no mass- which can only be found in a perfect vacuum. The absolute minimum sound that can be experienced in any atmosphere as theorized by mathematicians is -23dB, or Brownian motion.
Therefore, the ear is less sensitive to a 100-Hz sound than it is to a 1000-Hz sound. In general, Figure 16.37 reveals that the ear is most sensitive in the range of about 1–5 kHz, and becomes progressively less sensitive at higher and lower frequencies.
In general, the fundamental frequency of the complex speech tone – also known as the pitch or f0 – lies in the range of 100-120 Hz for men, but variations outside this range can occur. The f0 for women is found approximately one octave higher. For children, f0 is around 300 Hz.
The Difference In Hearing Frequencies
It has been proven that women have greater hearing sensitivity and are more sensitive to noise exposure at higher frequencies. They also have shorter latencies in their auditory brain‐stem responses and more spontaneous otoacoustic emissions than men.
The most dangerous frequency is at the median alpha-rhythm frequencies of the brain, 7 hz. This is also the resonant frequency of the body's organs.
The fundamental speaking frequency of humans can reach up to around 1kHz, although higher values than, say, 500Hz usually appear only while singing. The harmonics and non-tonal parts of speech can have relevant energy beyond 10kHz.
The bottom end of our hearing range is 20Hz, which is still just below the deepest notes that most of us normally make (around 85Hz). But a few individuals have managed to go much deeper.
With energy as great as 1100 dB, it would create enough gravity to cause a black hole to form, and an incredibly large one at that. Decibels are a logarithmic unit. That means 20 decibels isn't 2 times more powerful than 10 decibels, it's 10 times more powerful.
Hailey et al. For the first time in history, earthlings can hear what a black hole sounds like: a low-pitched groaning, as if a very creaky heavy door was being opened again and again.
In general, women speak at a higher pitch—about an octave higher than men. An adult woman's average range is from 165 to 255 Hz, while a man's is 85 to 155 Hz (see sources). Men's voices are generally deeper because the surge of testosterone released during puberty causes their vocal cords to elongate and thicken.
Decibel levels:
The sound of your own breathing – 10 dB. A whisper – 20 dB. A normal conversation – 60 dB. A noisy restaurant – 70 dB.
A study of noise on Airbus A321 aircraft reported levels of 60-65 decibels (dBA) before takeoff; 80-85 dBA during flight; and 75-80 dBA during landing. The outside of aircraft engines (around 140 dB at takeoff) and conditions on other aircraft may have higher or lower noise levels.
According to the results of our study, binaural beats and 432 Hz music are effective in reducing preoperative dental anxiety. Both methods decreased the anxiety. When two groups were compared, no statistical difference was found between them. However, the 432 Hz was found to be more effective in reducing the anxiety.
Frequency of 528 Hz also reduces total concentration of reactive oxidative species in brain tissue. Prolonged exposure to this sound wave showed reduction of anxiety related behaviors in rats. The results reveal that reduced anxiety is related to increased concentration of testosterone in brain.
ALPHA (8-12 Hz)
Alpha waves are those between 8 and 12(Hz). Alpha waves will peak around 10Hz. Good healthy alpha production promotes mental resourcefulness, aids in the ability to mentally coordinate, enhances overall sense of relaxation and fatigue.