Brain Sounds Binaural Beats

I thought the app "Binaural Beats" by Giorgio Regni was very cool but lacked the possiblility to mix the beats with ambience sounds or music to make them less creepy, So I made this "improved" version.. hope you like it!!!
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Brain wave activity represents mental state. It's activity can be stimulated by rhythmic pulses of sound matching frequency of brain waves you want to increase (i.e. 8-12hz range is associated with a relaxed state of mind, stimulation on that frequency could* help you to actually feel more relaxed)
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> 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 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
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INSTRUCTIONS
Use with stereo headphones only (binaural effect is NOT appreciable with speakers)
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PERMISSIONS
- phone state: For automatically pausing sessions when phone call is received. NO PERSONAL DATA IS COLLECTED AT ALL.
- inet/network: For showing ads.
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LICENCE
Independent branch of github.com/GiorgioRegni/Binaural-Beats
Open source (GPLv3). Email me &will send latest source code!
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MORE INFO

Binaural beats:

The brain produces a phenomenon resulting in low-frequency pulsations in the amplitude and sound localization of a perceived sound when two tones at slightly different frequencies are presented separately, one to each of a subject's ears, using stereo headphones. A beating tone will be perceived, as if the two tones mixed naturally, out of the brain. The frequencies of the tones must be below 1,000 hertz for the beating to be noticeable.[3] The difference between the two frequencies must be small (less than or equal to 30 Hz) for the effect to occur; otherwise, the two tones will be heard separately, and no beat will be perceived.

i.e, if 300 Hz was played in one ear and 310 in the other, then the binaural beat would have a frequency of 10 Hz.

A constant timbre at a constant pitch is characterized by a spectrum. Along a piece of music, spectrum varies with the melody and the possible effects of instruments.

But a constant spectrum can be perceived as a melody because our ears are not an abstract spectrograph: they "calculate" Fourier's transform of the sound signal in a narrow time window, but the slower variations are seen as temporal evolution and not as pitch.
However, if a melody contains no infrasound (i.e. pure tone of period slower than the time window) ! When two pitches are very close, they create a beat. If its period is longer than the integration window, it is seen as a sinusoidal variation in the average rating: sin(2π(f+ε)t) + sin(2π(f-ε)t) = sin(2πft)cos(2πεt), where 1/ε is the slow period.

https://fr.wikipedia.org/wiki/Psychoacoustique

illusory continuity restores perceptual continuity of obscured sounds,
https://en.wikipedia.org/wiki/Illusory_continuity_of_tones

illusory discontinuity disrupts the perception even if the sound is indeed continuous.
https://en.wikipedia.org/wiki/Illusory_discontinuity

Listeners strongly susceptible to illusory discontinuity do not perceive illusory auditory continuity