Hearing range usually describes the range of frequencies that can be heard by an
animal or human, though it can also refer to the range of levels. In humans the audible
range of frequencies is usually said to be 20 Hz (cycles per second) to 20 kHz (20,000
Hz), although there is considerable variation between individuals, especially at the high
frequency end, where a gradual decline with age is considered normal. Sensitivity also
varies a lot with frequency, as shown by equal-loudness contours, which are normally
only measured for research purposes, or detailed investigation. Routine investigation for
hearing loss usually involves an audiogram which shows threshold levels relative to a
standardised norm.

In a human, sound waves funnel into the ear via the external ear canal and hit the
eardrum (tympanic membrane). Consequently the compression and rarefaction of the
wave set this thin membrane in motion, causing the inner ear bones (the
ossicles;
malleus, incus and stapes) to move.
The number of sound pressure level vibrations (sonic waves) per second denotes the frequency. Infrasonic (below hearing), sonic (aural), and ultrasonic
(above hearing) frequencies are measured in Hertz (Hz); one Hertz is one cycle wave (or singular pressure wave in audionics) per second. Specifically in
humans, we have a maximum aural range of 12 Hz under ideal laboratory conditions[2] to 20,000 Hz in some individuals, but the range shrinks during our
lifetime, usually beginning at around the age of 8 with the higher frequencies fading. Inaudible sound waves can be detected (felt) by humans via infrasonics
through physical body vibration in the range of 4 to 16 Hz. There is a difference in sensitivity of hearing between the sexes, with women typically having a
higher sensitivity to higher frequencies than men (Gotfrit 1995). The vibrations of the ossicular chain displace the basilar fluid in the cochlear, causing the
hairs within it, called
Stereocilia, to vibrate. Hairs line the cochlear from base to apex, and the part stimulated and the intensity of stimulation gives an
indication of the nature of the sound. Information gathered from the hair cells is sent via the auditory nerve for processing in the brain.
How We Hear
About Subliminal Messaging
What are subliminal messages?
What is subliminal audio and what are subliminal messages? How could they
possibly help you or someone you know, and how can you benefit from this tool?
You may not be aware of fairly recent advances in subliminal audio technology
that makes this all possible. Just in case you don't have any experience with
subliminal self help or never really considered using it, here's a quick
explanation.

In our case they are positive affirmations that are being presented to the listener
above the normal threshold of our ear’s normal audio capacity to understand.
Yet the inner ear can pick them up and your subconscious can understand, and
if you really want to change, in most cases will there is a very good chance you
will react to them in a beneficial manner.  

These “affirmations are very similar to the ones you read about in today’s Self
Hypnosis books or are on the self help web sites. They are, “I can be this”, or, “I
am that” types of messages you will audibly say to your self everyday at certain
times. These techniques work, if not why would there be so many people using
them?  At The Subliminal Mind we engineer them for those who do not have the
time to stop and look into a mirror and say them.
Our music with “Brainwave Synchronization” frequencies is designed to make it a pleasure to listen to, while at the same time, get your “never sleeping”,  
subconscious mind the positive affirmations you need as you sleep or while taking a quiet break.  In order for us to achieve this with the most positive
influences, the player acts as a third person speaking the affirmations, much like someone talking to you directly i.e. “You are great!”,  “You can do it better
than anyone else”.   Think about it for a moment, some of us have heard our whole lives how we would never be able to be someone we wanted to be, or we
can’t do this or that. We have self doubt, we can’t sleep with all of today’s stressful situations or we even have high blood pressure.  Don’t you think it’s about
time to hear the opposite!  Don’t you agree it is time to take charge of your own life? With this technology and a true desire to be successful you now can.
So how is it done?
We archive this by moving the messages voice to a frequency into the
upper portion of human hearing. We don’t want to hear audibly but we still
want it to vibrate the inner ear so our brain can still decode it. As we have
shown, human ears can possibly hear things from 20Hz up to around
20KHz so by moving our messaging voice up to 16.5KHz ( see Figure I)  
then apply a filter to filter out anything above or below 16.5KHz we can
end up with a recording that is still playing very load but you will not hear
affirmation messages, well at least you think you're not hearing anything
but in fact you really are. Once we add music to the sound track (See
Figure II and III) the voice is completely covered while you still hear the
affirmations at the upper frequency level.
FIGURE I
FIGURE 2
FIGURE 3
About Bio Rhythm and Brainwave Synchronization.
One of the techniques that we use at The Subliminal Mind, is to engineer sound frequencies that stimulate brain waves making the
brain more susceptible to subliminal suggestions. There are two frequency settings these that can be changed from 10 to 600Hz.
The difference between the tones will fall within the following ranges:

For example we will set frequency [A] to 80 Hz and frequency [B] will be set at 85 for a meditative state. Another example if you want
to make one for an awake state, We want your brain to be in an Alpha State which is a 7 to 12Hz difference between frequency [A]
and frequency [B] so we set frequency [A] at 80 and frequency [B] can be 86 to 92. In this way we can help determine if the person
will be sleeping or just relaxing.
 
In conclusion;
Subliminal messages are not dangerous and can not make you do things against your will. For example, this is not a, “magic pill” for
weight loss or to quit smoking. Modification can only take place if a person wishes to accept the change first. The positive suggestions
or “Affirmations” need to be something you originally and consciously want to happen. Then your subconscious mind will be willing to
accept the changes you desire. That is why it is very important that you make sure you read all of the affirmations first before using
this type of medium.  

Subliminal messaging (in the form of subliminal CDs, subliminal MP3s or subliminal visual imagery) is a proven tool and has been
recommended by leading professionals, psychologists and physicians worldwide. However, in the beginning, the use of subliminal
learning can irritate some people as it conflicts with their already established powerful habits.

Still, subliminal messaging is the quickest and easiest method of effecting powerful and lasting personal change.  It is more like a
plug'n'play system – you just turn it on, listen and let your subconscious mind handle the details. The subconscious mind is extremely
receptive; you can learn or change habits while sleeping or awake. Subliminal audio doesn't need much attention, and it will not steal
from your time. Subliminal means that your Conscious Mind will be unaware of the suggestions for change, as they will be directed
entirely to your subconscious mind. Consciously you will not be aware of the spoken words; however, subconsciously, your mind is
aware and able to act upon each suggestion for change. Not only do you have greater latitude in playing each subliminal recording,
you may even find it more effective than Self Hypnosis CDs. This is true if you tend to be analytical and/or critical in your thinking;
because, by masking the suggestion for change under pleasurable music or gentle nature sounds, your Conscious Mind has nothing
to analyze or criticize and this can help affect change in a nearly effortless process. To enhance the power of subliminal recordings, I
suggest that you listen every day for one hour - for 3 weeks or more.