Audio and the Human Mind

Infrasound

Infrasound is sound that is lower in frequency than 20 Hz (Hertz) or cycles per second, the "normal" limit of human hearing. Hearing becomes gradually less sensitive as frequency decreases, so for humans to perceive infrasound, thesound pressure must be sufficiently high. The ear is the primary organ for sensing infrasound, but at higher levels it is possible to feel infrasound vibrations in various parts of the body.

One study has suggested that infrasound may cause feelings of awe or fear in humans. It was also suggested that since it is not consciously perceived, it can make people feel vaguely that supernatural events are taking place.

http://en.wikipedia.org/wiki/Infrasound

Exposure to infrasound has been demonstrated to effect recipients with symptoms including fear, sorrow, depression, anxiety, nausea, chest pressure and hallucination. It can cause objects to move through vibration and some believe the body’s internal organs can be effected. It is suggested that levels above 80 decibels at frequencies between 0.5 to 10Hz may start to effect the vestibular of the inner ear thus causing disorientation. Any high volume sound can trigger the body to react by increasing respiration, heart rate and blood pressure, but when they cannot actually hear the sound recipients are left with no explanation for the sudden onset of these symptoms.

http://www.eastcoastrip.org/did-you-know/infrasound


Binaural beats

Binaural beats or binaural tones are auditory processing artifacts, or apparent sounds, the perception of which arises in the brain for specific physical stimuli.

Our brain pulses and vibrates like everything in this Universe. The brain pulse is measured like sound in cycles per second or Hertz. The machine used to make the measure is called an ElectroEncephaloGraph (EEG). While this machine has its limitation, we can still use it to categorize brain activity with more or less accuracy

Frequency range	Name	Usually associated with:
> 40 Hz	Gamma waves	Higher mental activity, including perception, problem solving, fear, and consciousness
13–39 Hz	Beta waves	Active, busy or anxious thinking and active concentration, arousal, cognition, and or paranoia
7–13 Hz	Alpha waves	Relaxation (while awake), pre-sleep and pre-wake drowsiness, REM sleep, Dreams
8–12 Hz	Mu waves	Sensorimotor rhythm Mu_rhythm, Sensorimotor_rhythm
4–7 Hz	Theta waves	deep meditation/relaxation, NREM sleep
< 4 Hz	Delta waves	Deep dreamless sleep, loss of body awareness

http://www.psychic101.com/brainwaves-beta-alpha-delta.html