Method and apparatus for optimization of binaural beat

Abstract

An apparatus for optimizing a binaural beat according to an embodiment of the present invention includes: a binaural beat generator that generates a binaural beat; and a binaural beat controller that optimizes the binaural beat in consideration of a hearing state of left and right ears of a listener. A method for optimizing a binaural beat according to an embodiment of the present invention includes: generating a binaural beat; and optimizing the binaural beat in consideration of a hearing state of left and right ears of a listener.

Claims

1. An apparatus for optimizing a binaural beat comprising: a binaural beat inducing sound source generator that generates a sound source for allowing a listener to feel a binaural beat; and a binaural beat controller that controls a binaural beat effect in consideration of a hearing state of left and right ears of the listener, wherein the binaural beat inducing sound source generator comprises a sound transmitting device that makes sounds independently to left and right ears of the listener by making direct contact with the left and right ears of the listener respectively, wherein the binaural beat inducing sound source induces a binaural effect by generating a sound source to be heard by the left and right ears by the listener in response to a selection of a volume of the sound and a binaural beat frequency selected by the listener or a user, and generates the binaural beat by generating a sound source to be heard in both ears using a reference frequency, a sound level and a binaural beat frequency selected by the listener or the user; wherein the binaural beat controller optimizes the binaural beat by adjusting volumes of sounds heard by the listener in the left and right ears according to a difference in left and right hearings of the listener, wherein the binaural beat controller optimizes the binaural beat so that the listener feels left and right sounds at a same level, and wherein the hearing state of the left and right ears of the listener comprises a difference in hearings of the left and right ears, and wherein the difference in the hearings of the left and right ears of the listener is estimated from a difference in a magnitude of a sound source that compensates hearing of the listener so that volumes of sound heard in both ears are the same.

2. The apparatus of claim 1, wherein the binaural beat inducing sound source generator generates the binaural beat using a sound source that gives a tone according to a specific purpose or adds a preferred musical element to a background sound source.

3. The apparatus of claim 1, wherein the binaural beat inducing sound source generator induces the binaural beat effect to the listener using a sound source that gives a tone according to a specific purpose or adds a preferred musical element to a background sound source.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is a graph showing a magnitude of a binaural beat felt by a listener when there is a difference in the amount of left and right sounds felt by a listener.

(2) FIG. 2 is a graph showing an intensity or a magnitude of a beating that is visualized as a depth of an envelope in a beating signal in which signals of two sounds having different frequencies are combined.

(3) FIG. 3 is a conceptual block diagram of an apparatus for optimizing a binaural beat according to an embodiment of the present invention.

(4) FIG. 4 is a flowchart illustrating a binaural beat generation process performed by a binaural beat generator of a binaural beat optimization apparatus according to an embodiment of the present invention.

(5) FIG. 5 is a flowchart illustrating a binaural beat adjustment process performed by a binaural beat controller of a binaural beat optimization apparatus according to an embodiment of the present invention.

DETAILED DESCRIPTION OF THE EMBODIMENTS OF THE INVENTION

(6) Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

(7) FIG. 1 is a graph showing a magnitude of a binaural beat felt by a listener when there is a difference in the amount of left and right sounds felt by a listener. FIG. 1 shows the change in the strength of the binaural beat felt by 34 listeners using the SDM (Semantic Differential Method) evaluation tool when a difference in a magnitude of left and right sounds increases while reducing the magnitude of a presented sound compared to a reference sound. In FIG. 1, the horizontal axis represents the amount of reduction of the sound pressure level (SPL) of the presented sound compared to the reference sound in dB, and the left vertical axis shows the change in the relative strength of the binaural beat. The right vertical axis shows a percentage (0% to 100%) of the range of 0 to −4 of the evaluation tool scale. The experiments were repeatedly performed while a reference sound was separately provided to the left ear and the right ears, and in FIG. 1 the positions of the reference sound and the presented sound heard in the opposite ear are shown separately. The strength of the binaural beat was found to be greatest when there was no difference in the magnitudes of the reference sound and the presented sound, that is, when there was no difference in the magnitudes of the left and right sounds. When a difference in a magnitude of the left and right sounds is small, the strength of the binaural beat remains similar at the beginning, but when the difference in the sound pressure level of the left and right sounds becomes to be greater than 2.2 dB, the strength of the binaural beat starts to decrease significantly and decreases rapidly if the difference in sound pressure level of the left and the right sounds becomes to be greater than 4.9 dB.

(8) FIG. 2 shows typical beating signals composed of two sound sources having amplitudes of A.sub.1 and A.sub.2 and frequencies of f.sub.1 and f.sub.2, respectively. FIG. 2 (a) shows the case where the amplitudes of two sound sources are the same (i.e., A.sub.1=A.sub.2), and FIG. 2 (b) shows the case where the amplitude of one sound source is half the amplitude of the other sound source (i.e., A.sub.1=A.sub.2/2). The binaural beating frequency f.sub.b corresponds to the difference between the two frequencies, and the oscillating frequency f is an average of the two frequencies. The beat magnitude (M) is defined as the depth of the envelope of the beating. Referring to FIG. 2 (a), the strength of the beating is greatest in comparison with the magnitudes of two sounds when the magnitudes of two sounds having different frequencies are the same. On the other hand, referring to FIG. 2 (b), as the difference between the magnitudes of the two sounds forming the beating increases, the strength of the beating decreases relatively. For this reason, the strength of the binaural beat perceived subjectively is also expected to be greatest when the magnitudes of the sounds provided to both ears are the same. It is also estimated that the strength of the binaural beat felt through the hearing organs will be different if the hearings of the left and right ears are different even if the same sound is heard in both ears.

(9) An apparatus and a method for optimizing a binaural beat according to an embodiment of the present invention optimizes the binaural beat by reflecting the listener's left and right hearing states in consideration of the above-mentioned points. The left and right hearing states may include a difference in left and right hearings, and an apparatus and a method for optimizing the binaural beat according to an embodiment of the present invention may optimize the binaural beat by reflecting the difference in left and right hearings of the listener.

(10) FIG. 3 shows a conceptual block diagram of an apparatus for optimizing a binaural beat according to an embodiment of the present invention. The binaural beat generator 10 generates a binaural beat, and the binaural beat controller 20 receives the generated binaural beat and optimizes the binaural beat by reflecting the difference in left and right hearings of the listener. The binaural beat controller 20 may optimize the binaural beat by adjusting the volume balance of the left and right sound sources.

(11) FIG. 4 shows a flowchart showing a binaural beat generation process performed by the binaural beat generator 10 of the apparatus for optimizing the binaural beat according to an embodiment of the present invention, and FIG. 5 shows a flowchart showing a binaural beat adjustment process performed by the binaural beat controller 20 of the apparatus for optimizing the binaural beat according to the present invention. Hereinafter, a method for optimizing a binaural beat will be described with reference to FIG. 4 and FIG. 5.

(12) The binaural beat generator 10 may generate a binaural beat using a reference frequency, a binaural beat frequency and a reference volume, which are basic information determined by a user. Here, the reference volume may be set to correct a volume sensitivity, a preference difference, and the like for each listener. The binaural beat controller 20 adjusts the magnitude of the binaural beat generated by the binaural beat generator 10. For example, the binaural beat controller 20 may adjust the binaural beat to maximize the strength of the binaural beat so that the listener who hears a sound source divided into left and right feels the same sound magnitude in both ears.

(13) Specifically, referring to FIG. 4, the binaural beat generator 10 selects a center frequency f.sub.0 of a sound source to be heard by a listener (S41). For example, the listener may select a desired center frequency through the input interface, and the binaural beat generator 10 may set the frequency selected by the listener as the center frequency.

(14) The binaural beat generator 10 selects the binaural beat frequency Δf (S42). For example, the listener may select a desired binaural beat frequency through the input interface, and the binaural beat generator 10 may set the frequency selected by the listener as a binaural beat frequency. For example, the binaural beat frequency may be selected as 10 Hz.

(15) The binaural beat generator 10 determines the binaural beat sound source frequency (f.sub.0±Δf/2) using the center frequency f.sub.0 and the binaural beat frequency Δf (S43). As a result, two binaural beat sound source frequencies are determined.

(16) The binaural beat generator 10 sets a reference volume SPL.sub.ref (S44). For example, the listener may select a reference volume he wants through an input interface, and the binaural beat generator 10 may set the volume selected by the listener as a reference volume.

(17) The binaural beat generator 10 may generate two binaural beat sound sources to be provided to the left and right ears through the above process, and the two sound sources have the same reference volume but respectively have different frequencies having a difference corresponding to the binaural beat frequency value.

(18) Meanwhile, the binaural beat generator 10 may generate a binaural beat using a sound source that gives a tone according to a specific purpose or adds a preferred musical element to a background sound source.

(19) FIG. 5 shows a flowchart showing a control process for optimizing the binaural beat performed by the binaural beat controller 20.

(20) The binaural beat controller 20 hears two binaural beat sound sources generated by the binaural beat generator 10 in the right and left ears (S51, S52).

(21) The listener who hears the binaural beat sound sources with both ears selects the direction in which the sound in one ear is smaller than the sound in the other ear (S53).

(22) The binaural beat controller 20 adjusts the volume of the sound of the corresponding ear after receiving information about the small-sounding ear selected by the listener (S54). At this time, the binaural beat controller 20 may increase the sound of the binaural beat sound source on the side where the sound is smaller.

(23) Subsequently, the binaural beat controller 20 provides again the binaural beat sound source having the adjusted magnitude of sound source to the right and left ears (S55, S56).

(24) Subsequently, the listener listens to two binaural beat sources through both ears, judges whether the magnitudes of the left and right sounds are the same and inputs the result. The binaural beat controller 20 determines whether the magnitudes of the left and right sounds are the same based on the information input by the listener (S57).

(25) If it is determined in step S57 that the magnitude of the right and left sound levels are the same, the binaural beat controller 20 determines that the sound magnitude is properly adjusted according to a difference in hearing between the left and right ears of the listener, and the adjusted binaural beat sound source is provided to the listener. On the other hand, if it is determined in step S57 that the right and left sound levels are not the same, the binaural beat controller 20 repeats steps S54, S55 and S56 again to further adjust the sound magnitude.

(26) While this invention has been described in connection with what is presently considered to be practical exemplary embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.