JP2832202B2 - Natural sound reproduction device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to an indoor environment sound generation device using natural sounds suitable for alleviating techno stress in an office or the like and creating a relaxation space.

[Conventional technology]

2. Description of the Related Art Conventionally, in offices and the like, so-called "environmental music", "sounds of waves", and "natural sounds" such as insect sounds have been used for the purpose of relaxing a worker's tension, changing his mood, and improving efficiency. In addition, stationary noise is used for the purpose of masking office equipment noise, conversation, telephone noise, and the like in offices, and the noise of adjacent dwelling units in hotels, apartment buildings, and the like.

[Problems to be solved by the invention]

However, in the case of "environmental music", its musical elements, for example, semantic information such as melodies and rhythms, become strongly conscious over time, and in many cases, it becomes uncomfortable and becomes unusable. Further, since "environmental music" is generally reproduced repeatedly through a physical medium such as a magnetic tape, the cycle is often perceived by a human, and the effect is often adverse.

Therefore, some "environmental music" is designed to emphasize melody and rhythm as little as possible.However, since human beings create it with a certain intention, it is important to suppress melody and rhythm as semantic information. Limits arise on their own.

In the case of "natural sound", in that it does not have specific semantic information, it can be said that it is suitable as a sound source for adding sound, but natural sound under conditions suitable for sound environment control is recorded for a long time. This is difficult due to the continuity of natural phenomena. In addition, from the viewpoint of the capacity of a recording medium such as a magnetic tape, if it is intended to cover the entire audio frequency band, recording for about two hours is currently limited. Therefore, when the time limit is exceeded, a method of repeatedly reproducing the same sound source is used. However, human hearing including the cerebral processing system has the ability to detect a period of several hours or more, so that even if it is played repeatedly for a long time, a specific pattern will eventually become conscious. There is a problem that it becomes uncomfortable.

In order to compensate for the disadvantages of environmental music, the use of stationary noise without semantic information has been considered. As they rattle, they become noisy. That is, there is a drawback that it is too monotonous.

An object of the present invention is to solve the above-mentioned problem, and an object of the present invention is to provide a natural sound reproducing device that can provide a mental relaxation without causing discomfort even if heard for a long time.

[Means for solving the problem]

For this purpose, the present invention provides a storage means for storing a plurality of sound material data corresponding to sound material numbers, a timing control means for storing generation timing data which is a time series of time intervals, and outputting a trigger signal at the time intervals. A sound material data selecting means for randomly outputting a sound material number in response to an input of a trigger signal, and a reproducing means for reproducing sound material data corresponding to the sound material number output by the sound material data selecting means. In this case, the time interval of the generation timing data is determined based on the amplitude value of the low frequency component after converting the noise into an effective value.

[Action]

In the natural sound reproducing apparatus of the present invention, a plurality of sound material data are stored in advance in the storage means which is a physical medium, and the sound material data is sequentially selected by the sound material transmitting means and transmitted at a predetermined timing. The sound material data is sequentially selected based on a rhythm (occurrence timing) in accordance with the actual state of the natural world, and transmitted to the reproducing means. This makes it possible to create an artificial environmental sound equivalent to a natural sound in terms of audibility in which the same pattern is not generated for a long time.

〔Example〕

 Hereinafter, embodiments will be described with reference to the drawings.

FIG. 1 is a diagram showing a configuration of an embodiment of a natural sound reproducing device according to the present invention, and FIG. 2 is a diagram showing a temporal change in amplitude of a fluctuation signal. In FIG. 1, A is a sound material storage unit, B is a sound material selection unit, C is a generation timing control unit, 1 is a memory,
2 is a buffer memory, 3 is a material selection signal control device, 4 is a selected data storage device, 5 is a timing control device, 6 is a time series data conversion device, 7 and 13 are A / D converters, 8 is a low-pass filter, 9 Is an RMS circuit, 10 is a fluctuation noise generator, 1
1 is a microphone, 12 and 16 are amplifiers, 14 is a D / A converter,
Reference numeral 15 denotes a volume control device, and reference numeral 17 denotes a speaker.

One of the fluctuation characteristics found in the natural world is what is called “1 / f fluctuation”. This can be said to be "a phenomenon in which the magnitude of the fluctuation is inversely proportional to the frequency of the fluctuation". “Fluctuation” means that a certain physical quantity fluctuates with the passage of time.
Sound power (sense of volume), frequency (feeling of pitch, tone),
And rhythm (timing of occurrence) are considered important. Many mysteries remain about the mechanism of “1 / f fluctuation”, but in our experience, comfortable sounds have “1 / f fluctuation” characteristics, and fluctuation characteristics such as unpleasant noise are “1”. It is known that the characteristic deviates from the "/ f fluctuation" characteristic.

Therefore, a plurality of natural sound elements are stored in analog or digital form in a physical storage device, and "1/1 /
When reproduced at the generation timing having the "f-fluctuation" characteristic, it is possible to create an environmental sound that is audibly equivalent to a natural sound and does not repeat indefinitely. In the present invention, this environmental sound is shown in FIG. It is created and reproduced by such a configuration.

In FIG. 1, a sound material storage unit A stores a plurality of natural sound material data composed of digitized short-time sound materials and a sound material data selected from the memory 1 for reproduction. The buffer memory 2 stores a plurality of natural sound materials. The sound material selection unit B includes a selection data storage device 4 and a material selection signal control device 3, and generates and stores a plurality of sound material number data for selecting data stored in the memory 1.
This controls selection of natural sound material data. The selection data storage device 4 stores a random number table or the like as selection data, and the material selection signal control device 3 performs an operation on the data generated in the selection data storage device 4 and assigns the data to the sound material number. A signal for selecting sound material data stored in the memory 1 as data is generated. The generation timing control unit C includes a timing control device 5, a time-series data conversion device 6, an A / D converter 7, a low-pass filter 8, an RMS circuit 9, and a fluctuation noise generation device 10, and controls the generation timing of natural sounds. It generates and stores data, and controls the generation of natural sounds.
The fluctuation noise generator 10 generates noise having 1 / f fluctuation characteristics, the RMS circuit 9 converts the noise into an effective value, and the low-pass filter 8 controls the RMS
The output of the circuit 9 is to obtain an amplitude fluctuation signal of a low frequency component as shown in FIG. 2, for example. And A /
The D converter 7 converts the output of the low-pass filter 8 into a digital signal, the time-series data converter 6 performs an operation on the digital data and converts the digital data into time-series data of an occurrence time interval, and the timing controller 5 It stores time-series data and sends a trigger signal to the buffer memory 2 and the material selection signal control device 3 based on the data.

In addition, microphone 11 and amplifier 1
2. The A / D converter 13 is a circuit for sampling the natural sound material stored in the memory 1. The D / A converter 14, the volume controller 15, the amplifier 16, and the speaker 17 are sequentially selected from the memory 1. The sound material stored in the buffer memory 2 is reproduced.

 Next, the operation will be described.

FIG. 3 is a diagram for explaining the content of the operation on the amplitude fluctuation signal, and FIG. 4 is a generation time interval (generation timing).
FIG. 4 is a diagram illustrating an example of data.

First, when the operation of the apparatus is started, generation timing data is generated as preparation. The procedure of generating the generation timing data is as follows: a noise signal having a fluctuation component generated by the fluctuation noise generator 10 is subjected to a predetermined process by the RMS circuit 9 and the low-pass filter 8 so that the amplitude fluctuation as shown in FIG. The signal is obtained, and the A / D converter 7 converts the signal into a digital signal at each time (sample number).

Then, the time-series data converter 6 performs normalization and calculation according to a predetermined reproduction time interval range, converts the digital signal into generation timing (occurrence time interval) data,
It is stored in the timing control device 5. For example, in the case of the amplitude fluctuation signal shown in FIG. 2, as shown in FIG. 3, a predetermined constant α (= 5 sec) is calculated with respect to the sound volume (E) normalized at each time (sample number) as shown in FIG. Multiplied by this E
The value of xα is data Δt (sec) of the occurrence time interval (occurrence timing) as shown in FIG.

When the above preparation is completed, reproduction is performed in the following procedure.

Based on the first data of sound material selection, sound material data in the memory 1 is selected and sent to the buffer memory 2.

After a time based on the first data of the generation timing, the timing control device 5 generates a trigger signal.

The data in the buffer memory 2 is output by the trigger signal and reproduced through the D / A converter 14, the volume controller 15, the amplifier 16, and the speaker 17.

At the same time, a material selection signal control device 3 by a trigger signal
Then, the second sound material number data is sent to the memory 1, and the sound material data is selected and sent to the buffer memory 2.

 The following operations are repeated.

The frequency of natural fluctuation is about 0.3H
Since it is found by experiment that the frequency is equal to or lower than z, the cutoff frequency in the low-pass filter 8 in the embodiment is 0.3 Hz as a representative value. In this case, the optimum value of the sampling frequency of the A / D converter 7 is 0.6 Hz (cycle 1.67 seconds), but this cycle is generally sufficiently shorter than the average generation cycle of the natural sound pattern. This means that, in other words, the generation speed of the generated timing data by the system from the fluctuation noise generator 10 to the time series data converter 6 is faster than the data output speed of the timing controller 5. Therefore, the generated timing data is sequentially accumulated in the memory of the timing control device 5 with the passage of time. In this case, the memory capacity of the timing control device 5 is a problem in the device configuration. However, assuming that the average natural sound generation period is a short value of 2 seconds, the number of generation timing control data required for 24-hour reproduction is This is about 43,000, and the memory capacity required to store the data in 4 bytes per data is about 170 kilobytes, which is a value that can be easily realized at present. In addition, the continuity of natural sound generation is interrupted depending on the memory capacity. However, when a general life pattern is considered, discontinuity in units of 24 hours does not substantially pose a problem.

Also, when generating timing data having a predetermined fluctuation characteristic by a logical operation of a computer,
The system of the time series data converter 6 from the fluctuation noise generator 10 can be replaced with this, and the memory of the timing controller 5 needs only a very small capacity for correcting the deviation from the average period. That is, discontinuity of natural sound reproduction can be prevented.

〔The invention's effect〕

In the case where natural sound is used as a sound source to which sound is added, a method of repeatedly reproducing the same sound source has conventionally been adopted due to a time limit caused by passing through a physical medium. According to, the short-time sound material recorded on the physical medium is reproduced based on the rhythm (occurrence timing) in accordance with the actual state of the natural world. It is possible to create an environmental sound equivalent to an unnatural sound and a sense of hearing, that is, a pseudo natural sound having a feeling close to a real natural sound. In addition, by preparing a plurality of sound materials, it is possible to eliminate the monotony when one sound material is used, and by replacing the natural sound material stored in the sound material storage unit, With the sound material of time, it is possible to easily realize the environment of each natural sound, for example, a plateau or a grassland for an insect voice, and a sea for a wave sound or a seagull voice. Moreover, by introducing a stochastic process in which the data at a certain point in time is dependent on some data before that point in the selection data of the sound material, an artificial environment sound closer to the actual natural sound can be obtained. Can also be created. Furthermore, environmental sound having another effect can be generated by simply creating the generation timing data of the natural sound material using a random number or by changing the data to other than the 1 / f fluctuation characteristic.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of an embodiment of a natural sound reproducing apparatus according to the present invention, FIG. 2 is a diagram showing a change over time of the amplitude of a fluctuation signal, and FIG. FIG. 4 is a diagram showing an example of occurrence time interval (occurrence timing) data. A ... Sound material storage unit, B ... Sound material selection unit, C ... Generation timing control unit, 1 ... Memory, 2 ... Buffer memory, 3 ... Material selection signal control device, 4 ... Selection data storage Device, 5 timing control device, 6 time-series data converter, 7 and 13 A / D converter, 8 low-pass filter, 9 RMS circuit, 10 fluctuation noise generator, 1
1 ... microphone, 12 and 16 ... amplifier, 14 ... D / A converter, 15 ... volume control device, 17 ... speaker.

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-64-57300 (JP, A) JP-A-2-59,000 (JP, A) JP-A-2-134164 (JP, A) JP-A-62 208100 (JP, A) (58) Field surveyed (Int. Cl. ⁶ , DB name) G10K 15/04

Claims (1)

(57) [Claims] 1. A storage means for storing a plurality of sound material data corresponding to sound material numbers, a timing control means for storing generation timing data which is a time series of time intervals, and outputting a trigger signal at the time intervals; A natural sound reproducing device comprising: sound material data selecting means for randomly outputting a sound material number in response to a trigger signal input; and reproducing means for reproducing sound material data corresponding to the sound material number output by the sound material data selecting means. A natural sound reproducing apparatus in which the time interval of the generated timing data is determined based on an amplitude value of a low frequency component obtained by converting noise into an effective value.