JP2009036603A - Method and system for evaluating sound quality of air-conditioning sound - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method and a system for evaluating the sound quality of air-conditioning sound and capable of appropriately evaluating a general sense of comfort of air-conditioning sound based on a human auditory function even by a simple evaluation technique using one psychoacoustic evaluation quantity. <P>SOLUTION: The method for evaluating the sound quality of air-conditioning sound and quantitatively evaluating the sound quality of air-conditioning sound on the basis of collected air-conditioning sound data includes an air-conditioning sound data collection procedure for collecting air-conditioning sound data to be evaluated (step S3); a sharpness computation procedure for drawing the spectrum of loudness, the loudness of sound, on the basis of collected air-conditioning sound data, determining the center of gravity of a spectral area, and computing sharpness having a higher value when the position of the center of gravity is closer to the high-frequency side (step S6); and a sound quality evaluation procedure for taking a value of computed sharpness as a psychoacoustic evaluation quantity and evaluating sound quality based on a human auditory sense on how one feels air-conditioning sound (step S8). <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a sound quality evaluation method and a sound quality evaluation system that are applied to sound quality evaluation of automobile air conditioning sound and the like, and quantitatively evaluate the sound quality of air conditioning sound based on collected air conditioning sound data.

Conventionally, for the purpose of quantitatively evaluating the sound quality of the air conditioner operation sound without requiring an expert, the collected sound waveform data is analyzed into predetermined frequency components, and each frequency component is analyzed. A sound quality detection method is known in which a fluctuation amount of a sound pressure level is obtained, and auditory correction is performed on the fluctuation amount based on data obtained in advance by an auditory experiment or the like (see, for example, Patent Document 1).
JP-A-3-82922

  However, in the conventional sound quality detection method, the fluctuation amount of each frequency component of the sound is measured and the auditory correction is performed according to the magnitude of the fluctuation sound pressure level (sound pressure amplitude). In the case of two sounds having the same pressure amplitude and different frequencies, there is a problem in that both of them are subjected to the same correction and cannot be evaluated according to the sense of hearing.

  In other words, the sound pressure amplitude of most sounds that come into contact with humans fluctuates with time, but depending on how the fluctuations occur, they feel uncomfortable or comfortable. For example, comparing the case where the sound pressure amplitude is the same and fluctuates at a frequency of 30 Hz, and the case where it fluctuates at a frequency of 300 Hz, the sound fluctuating at a frequency of 30 Hz fluctuates at a frequency of 300 Hz. The sound that fluctuates is stronger than the sound that is present, and the sound that fluctuates at a frequency of 300 Hz is weak. That is, it cannot be said that the conventional sound quality detection method considers the characteristics of human hearing.

  The present invention has been made paying attention to the above-mentioned problem, and is a simple evaluation method using one psychoacoustic evaluation amount, while providing a comprehensive feeling of air conditioning sound based on human auditory function. An object of the present invention is to provide a sound quality evaluation method and a sound quality evaluation system for air conditioning sound that can be appropriately evaluated.

In order to achieve the above object, in the present invention, in the sound quality evaluation method for air conditioning sound that quantitatively evaluates the sound quality of the air conditioning sound based on the collected air conditioning sound data,
Air conditioning sound data collection procedure for collecting air conditioning sound data to be evaluated;
From the collected air conditioning sound data, draw a loudness spectrum that is the loudness of the sound, find the center of gravity of the spectrum area, calculate the sharpness that becomes higher as the position of the center of gravity is higher,
A sound quality evaluation procedure for evaluating the sound quality of a person's audibility as to what kind of air conditioning sound is a psychoacoustic evaluation amount, and the sharpness value calculated by the sharpness calculation procedure;
It is provided with.

In the air conditioning sound quality evaluation system that quantitatively evaluates the sound quality of the air conditioning sound based on the collected air conditioning sound data,
Air conditioning sound data collection means for collecting air conditioning sound data to be evaluated;
From the collected air conditioning sound data, draw a spectrum of loudness, which is the volume of sound, find the center of gravity of the spectrum area, and sharpness calculation means to calculate the sharpness that becomes higher as the center of gravity position is on the high frequency side,
A sound quality evaluation means for evaluating the sound quality of the person's audibility as to what kind of air conditioning sound is a psychoacoustic evaluation amount using the sharpness value calculated by the sharpness calculation means,
It is provided with.

Therefore, in the sound quality evaluation method and sound quality evaluation system of the present invention, when the air conditioning sound data to be evaluated is collected, the loudness spectrum, which is the loudness, is drawn from the collected air conditioning sound data. Then, the centroid of the spectrum area is obtained, and the sharpness that is higher as the centroid position is higher is calculated. Then, the sound quality due to human hearing is evaluated using the calculated sharpness value as a psychoacoustic evaluation amount.
In other words, as evaluation words suitable for evaluating the air conditioning sound of automobiles and the like, for example, “violent”, “bulky”, “soft”, “cloudy”, “thick”, “spread”, Evaluation words such as “exhilarating” can be mentioned.
Among these evaluation words, “violent”, “bulky”, “soft” and “cloudy” which are rough factors can be mechanically evaluated by sound pressure level (noise level) which is a physical quantity. For this reason, the evaluation words to be subjected to psychoacoustic evaluation are “thick”, “spread”, and “exhilarating” excluding the rough factor.
Therefore, for the three evaluation words that are subject to psychoacoustic evaluation, if the subjective evaluation of psychoacoustics is performed in various patterns by the scale construction method, the pattern for fixing the loudness and changing the sharpness is It was found that the characteristic of the evaluation point with respect to the change in sharpness shows the same correlation that the lower the sharpness value, the higher the evaluation point.
This means that, among the many psychoacoustic evaluation quantities, when the sharpness value is used as the sound index for psychoacoustic evaluation, only the sharpness value is used as the sound index. This means that the quality of air-conditioning sound was comprehensively evaluated for the three evaluation words “exhilarating”.
As a result, although it is a simple evaluation method using one psychoacoustic evaluation amount, it is possible to appropriately evaluate the sense of overall comfort of the air-conditioned sound based on the human auditory function.

  Hereinafter, the best mode for realizing a sound quality evaluation method and a sound quality evaluation system for air-conditioning sound according to the present invention will be described based on Example 1 shown in the drawings.

First, the configuration will be described.
FIG. 1 is a schematic overall view showing a sound quality evaluation system for automobile air conditioning sound (an example of air conditioning sound) according to the first embodiment.

  As shown in FIG. 1, the sound quality evaluation system for automobile air-conditioning sound according to the first embodiment includes a left microphone 1L, a right microphone 1R, an A / D converter 2, a personal computer 3, an instrument panel 4, and an air conditioner. A unit 5, a blower fan 6, a central vent outlet 7, a left vent outlet 8, and a right vent outlet 9 are provided.

  The left microphone 1L and the right microphone 1R are mechanical operation sound from an air conditioning unit 5 having a blower fan 6 built in an instrument panel 4, a central vent outlet 7, a left vent outlet 8, and a right vent outlet. The vent air blowing sound blown from 9 is input as an analog signal waveform. When collecting sound source data with both microphones 1L and 1R, assuming the driver sitting in the driver's seat of the right-hand drive car, the left microphone 1L is set to a position corresponding to the driver's left ear, and the right microphone 1R Is set to a position corresponding to the right ear of the driver. Similarly, when evaluating the air-conditioning sound felt by passengers sitting in the front passenger seat and rear seat, both microphones 1L and 1R can be set at positions corresponding to the left and right ears of the front passenger and rear passenger. Done.

  The A / D converter 2 converts the sound wave form of analog signals from the left and right microphones 1L and 1R into a digital signal (= sound source data).

  The personal computer 3 uses the sound source data from the A / D converter 2 as input information, quantitatively analyzes the sound quality of the automobile air-conditioning sound according to how it is perceived by the person using psychoacoustic technology, and evaluates by analysis Display the results. The personal computer 3 is installed with the sound quality evaluation software for automobile air conditioning sound according to the first embodiment.

  As shown in FIG. 1, the personal computer 3 includes a sound source data storage unit 31, an arithmetic processing unit 32, a database 33, a sound quality evaluation unit 34, a display command unit 35, a display monitor 36, and a keyboard 37. And a computer main body 38.

  The sound source data storage unit 31 stores the sound source data from the A / D converter 2 and accumulates the amount of sound source data necessary for sound quality evaluation.

  Based on the sound source data read from the sound source data storage unit 31, the arithmetic processing unit 32 executes calculation of sound pressure levels, comparison of sound pressure levels, calculation of sharpness, and selection of sound source data for evaluation.

  The database 33 stores a plurality of pre-established evaluation sound source data (evaluation scales based on sharpness values) based on the result of subjective evaluation by the scale construction method, and in response to a selection command from the arithmetic processing unit 32. The evaluation sound source data to be used as the evaluation reference is selected from the plurality of evaluation sound source data. Here, the plurality of evaluation sound source data stored and set means, for example, data set for each vehicle type, each air conditioning unit model, each blower rotation speed, and the like.

  The sound quality evaluation unit 34 quantitatively analyzes the vehicle air-conditioning sound according to how the person feels by comparing the sharpness value calculated by the arithmetic processing unit 32 with the sound source data for evaluation selected from the database 33. Evaluate as a result. As an evaluation method, not only whether it is OK or NG, but, for example, evaluation is made up to which position in the OK region or NG region the calculated sharpness value exists so as to be an improvement guideline for the air conditioning unit 5 .

  The display command unit 35 commands the display monitor 36 to display the sound quality evaluation result based on the evaluation result of the sound quality evaluation unit 34. The display monitor 36 not only displays the current evaluation of the vehicle air-conditioning sound output by the sound quality evaluation unit 34 in an easy-to-see manner, but also displays comments that serve as improvement guidelines for the air-conditioning unit 5.

  FIG. 2 is a flowchart showing the flow of the sound quality evaluation process of the automobile air conditioning sound executed by the personal computer 3 of the first embodiment. Each step will be described below. Note that this flowchart starts processing when a sound quality evaluation start operation is performed with the keyboard 37 or a mouse after the evaluation test environment for collecting sound source data is prepared.

  In step S1, the sound source data from the A / D converter 2 is stored when the sound quality evaluation is started or after determining that the necessary data amount has not been reached in step S2, and the process proceeds to step S2.

  In step S2, following the storage of the sound source data in step S1, it is determined whether or not the data amount necessary for calculating the sharpness is accumulated. If YES (accumulation of the necessary data amount), the step is performed. The process proceeds to S3, and in the case of NO (the required data amount is insufficient), the process returns to Step S1.

  In step S3, following the determination that the necessary data amount has been accumulated in step S2, the sound source data to be evaluated stored in the sound source data storage unit 31 is read, and the process proceeds to step S4 (air conditioning sound data collection). means).

In step S4, following the reading of the sound source data in step S3, the sound pressure level (SPL) is calculated, and the process proceeds to step S5 (sound pressure level calculation means).
Here, “sound pressure” is the magnitude of the pressure change of a sparse / dense wave that travels in the air, and “sound pressure level” is the logarithmic (log) ratio of the sound pressure at the measurement point to the reference value. It is a representation. The unit is dB (decibel). The “noise level” is the same as the “sound pressure level” in the definition formula itself, but instead of using the sound pressure signal p as it is, a predetermined bandpass filter (such as 40phon) is used in order to match the human hearing. This is the one using the result (signal pA) through the inverse characteristic of the sensitivity curve, that is, the frequency weighting characteristic A).

In step S5, following the calculation of the sound pressure level in step S4, it is determined whether the sound pressure level of the large class is 60 dB or less. If YES (sound pressure level ≦ 60 dB), the process proceeds to step S6, and NO. In the case of (sound pressure level> 60 dB), the process proceeds to step S9 (sound pressure level determination means).
Here, “60dB” is the set sound pressure level, and the impression of rough factors such as “violent”, “bulky”, “soft”, and “cloudy” as the evaluation words of air conditioning sound is Since the noise level that is not worrisome is 60 dBA or less, the sound pressure level 60 dB corresponding to the noise level 60 dBA is determined as the set sound pressure level.

In step S6, following the determination that the sound pressure level is 60 dB or less in the L class in step S5, the sharpness is calculated based on the sound source data read in step S3, and the process proceeds to step S7 (sharpness calculation). means).
Here, “sharpness” is one of the psychoacoustic evaluation quantities and represents the height of the sound (the sharpness of the sound) that is felt when the balance between the low-frequency and high-frequency sounds is biased toward the high frequency range. Yes, the unit is acum.
In this sharpness calculation method, first, the loudness, which is the loudness, is calculated based on the sound source data. Then, a loudness spectrum is drawn, the centroid of the spectrum area is obtained, and the distance from the frequency origin to the centroid position is obtained. This distance is sharpness, and the higher the position of the center of gravity is on the higher frequency side, the higher the value.
Basically, the above-mentioned sharpness calculation method is used, but this calculation may not match human hearing. Therefore, in order to correct this, a weighting factor is applied to the loudness for each critical band, and then the center of gravity of the loudness spectrum is obtained.

In step S7, following the calculation of sharpness in step S6, the evaluation sound source data corresponding to the sound quality evaluation environment of the vehicle air-conditioning sound being executed is selected from the plurality of evaluation sound source data stored and set in the database 33. Is selected, and the process proceeds to step S8.
Here, in the database 33, the subjective evaluation by the scale construction method based on the sharpness is selected for “thick”, “exhilarating”, and “spread” selected as evaluation words suitable for evaluating automobile air conditioning sound. A plurality of sound source data for evaluation obtained by performing is stored and set. FIG. 3 shows an example of evaluation sound source data.

In step S8, following the selection of the evaluation sound source data in step S7, the vehicle air conditioning sound is obtained by comparing the sharpness value calculated in step S6 with the evaluation sound source data selected from the database 33 (for example, FIG. 3). And the process proceeds to step S9 (sound quality evaluation means).
For example, as shown in FIG. 3, when the sharpness value is between 1.0 acum and 1.4 acum, the evaluation of all selected evaluation words (“thick”, “exhilarating”, “spread”) It is evaluated as a car air-conditioning sound with high sound quality.
Here, the sound that is the standard for sharpness is a narrow-band noise centered at 1 kHz, a sound pressure level of 60 dB with a bandwidth of 1 Bark, and the sharpness at this time is 1.0 acum.

In step S9, following the determination that the sound pressure level> 60 dB in step S5 or the evaluation of the vehicle air conditioning sound by comparison in step S8, a command to display the evaluation result of the vehicle air conditioning sound on the display monitor 36 of the personal computer 3 Is output and the process moves to the end.
Here, the content displayed on the display monitor 36 is, for example, when the sound pressure level is determined to be> 60 dB in step S5, for example, the sound pressure level as a mechanical evaluation result is displayed and how much the sound pressure level from the current state is displayed. Displays whether it is necessary to lower the value.
When the vehicle air conditioning sound is evaluated by comparison in step S8, for example, the calculated sharpness value is displayed over the evaluation sound source data shown in FIG. When the interval is between, OK is displayed, and when the sharpness value is other than 1.0 acum to 1.4 acum, NG is displayed. In addition, in the case of OK display, a comment is displayed to indicate whether it is just OK or OK with a margin, including the deviation from the midpoint of the OK area. In the case of NG display, in order to indicate the improvement target, the amount of deviation from the OK region to the higher value side and the amount of deviation from the OK region to the lower value side are displayed.

Next, the background to the present invention will be described.
Conventionally, automobile air conditioning sound has been evaluated for sound pressure level and frequency characteristics measured using a sound level meter. As described above, it has been found that the evaluation based on the physical factor measured by the sound level meter is insufficient and inappropriate to express the human subjective feeling.

  In recent years, noise reduction of the engine and improvement of the sound insulation performance of the body have been achieved, the quietness of the vehicle interior has been greatly improved, and only the air conditioning sound is being recognized as noise in the vehicle interior. However, air conditioning sound using a blower as a sound source cannot be evaluated according to the sense of hearing if only the sound pressure level and frequency characteristics are evaluated while improving air conditioning performance and reducing noise.

  For example, as shown in FIGS. 4A and 4B, when the sound pressure amplitude is the same and fluctuates at a frequency of 30 Hz (FIG. 4A) and fluctuates at a frequency of 300 Hz ( When comparing FIG. 4 (b)), a sound that fluctuates at a frequency of 30 Hz is more fluctuating than a sound that fluctuates at a frequency of 300 Hz, and a sound that fluctuates at a frequency of 300 Hz is weak. .

For such situations, there is a limit to mechanical evaluation based on conventional physical quantities (noise level, sound pressure level, sound power, frequency characteristics, etc.), so psychoacoustic evaluation quantities (loudness, Sound quality evaluation based on loudness level, sharpness, roughness, fluctuation intensity, etc.) has attracted attention as a sound improvement technique.
The “loudness” is the loudness of sound, and the unit is sone.
The “loudness level” is a logarithmic display of loudness, and is expressed in units of phon.
The “sharpness” is the height of the sound, and the unit is acum.
The “roughness” is a feeling of roughness that is felt when the loudness fluctuates in a short cycle, and is based on asper.
The “fluctuation strength” is a sense of fluctuation that is felt when the loudness fluctuates in a slow cycle, and is expressed in units of vacil.

  By introducing sound quality evaluation based on this psychoacoustic evaluation amount, for example, even if the sound pressure level is the same, the sound quality improvement that changes “noisy sound” to “comfortable sound” and “sound that you care about” are “friendly” If the sound quality is changed to “sound”, it can be recreated into a comfortable sound environment for humans who actually hear the sound.

  Psychoacoustic evaluation quantities (loudness, loudness level, sharpness, roughness, fluctuation intensity, etc.) based on human sound sensations are different indicators, so the sound quality that makes them “comfortable sound” and “friendly sound” In order to improve, it is said that taking a comprehensive sound quality evaluation method using a multidimensional evaluation index (= a plurality of psychoacoustic evaluation amounts) is important for improving the evaluation accuracy.

  However, the psychoacoustic evaluation amount is derived from the result of examining the structure of the human ear and the function of the auditory nerve or conducting audibility tests on many humans. The audibility test is to actually listen to the sound of human beings, listen to how they felt, and examine the reaction.Sounds gradually vary depending on the surrounding environment such as age, past experience, physical condition and temperature. The response to is different. Therefore, the psychoacoustic evaluation amount is obtained by testing many people many times and statistically processing them.

  Therefore, if a sound quality evaluation based on a plurality of psychoacoustic evaluation quantities selected from the psychoacoustic evaluation quantities “loudness”, “loudness level”, “sharpness”, “roughness”, “variation intensity”, etc. is performed, It takes a lot of time to create and requires complicated evaluation calculation processing by multi-dimensions, etc. Even if it is desired to introduce sound quality evaluation by psychoacoustic evaluation amount, these become obstacles to practical use It was left as a research subject to be solved in the future.

In response to a sound quality evaluation request based on a psychoacoustic evaluation amount with respect to an automobile air conditioning sound, the present inventor provides a plurality of evaluation words suitable for evaluating an automobile air conditioning sound when “sharpness” is used as a sound index in the psychoacoustic evaluation amount. We focused on the point that the sound quality was evaluated comprehensively.
In accordance with this point of interest, the calculated sharpness value was used as the psychoacoustic evaluation value, and a configuration was adopted in which the sound quality based on the audibility of the person as to what kind of feeling of the air conditioning sound was evaluated.
By adopting this configuration, it is possible to perform comprehensive sound quality evaluation for a plurality of evaluation words with one psychoacoustic evaluation amount without performing sound quality evaluation based on a plurality of psychoacoustic evaluation amounts.

Next, the operation will be described.
Hereinafter, the effects in the sound quality evaluation method and sound quality evaluation system of the automobile air-conditioning sound of Example 1 are referred to as “selection action of evaluation words of automobile air-conditioning sound”, “factor analysis action of evaluation words”, and “subjectivity based on psychoacoustic evaluation amount The description will be divided into “evaluation action” and “sound quality evaluation action of automobile air conditioning sound”.

[Selection action of evaluation word for automobile air conditioning noise]
As a preliminary experiment, the present inventor selected an evaluation word suitable for evaluating automobile air-conditioning sound using a description selection method by 17 subjects.
In this description selection method, an evaluation word suitable for evaluating the vehicle air-conditioning sound was selected by the subject from the 120 evaluation words shown in FIG. Based on the results of this experiment, cluster analysis using Pearson correlation was performed.
As a result, seven evaluation words (“thick”, “soft”, “bulkyness” having a high selection rate among the 120 evaluation words (selectivity 15% or more) and a high standard deviation among the 120 evaluation words. ”,“ Exhilarating ”,“ cloudy ”,“ violent ”,“ spread ”) were selected as evaluation words suitable for evaluating automobile air conditioning sound.

“Factor analysis of evaluation words”
Next, the present inventor classified seven evaluation words suitable for evaluating automobile air-conditioning sound into the following three factors by factor analysis.
1) "Intense", "bulky", "soft", "cloudy" ... crude factor
2) “Thick”, “Spread”… Spatial factors
3) “Exhilarating”: Exhilarating factor As shown in FIG. 6, a high positive correlation is found between the rough factor and the noise level. From this, it can be said that the impression of automobile air-conditioning noise such as “violent”, “bulky”, “soft”, and “cloudy” greatly contributes to the noise level. In addition, since the factor score is negative when the noise level is about 60 dB (A) or less, it can be said that the impression of the coarse factor is not noticeable in terms of hearing by suppressing the noise level to 60 dB (A) or less.

  Moreover, a high correlation is not seen between a spatial factor and a noise level as shown in FIG. From this, it is thought that the spatial factor is evaluating sound quality other than the noise level, and by investigating the evaluation amount highly correlated with the spatial factor, the spatial factor is “thick” and “spread” The impression may be improved.

  In addition, a negative correlation is seen between the refreshing factor and the noise level as shown in FIG. From this, it is considered that the impression of “exhilarating” can be obtained by reducing the noise level, but the rate of change with respect to the noise level is not as great as the crude factor, and the improvement of the exhilarating feeling by reducing the noise level is not so much I can't expect it.

  From the results obtained so far, it has been found that the evaluation factor different from the noise level of the vehicle air-conditioning sound can be an index for noise improvement because the spatial factor and the refreshing factor are less dependent on the noise level.

[Subjective evaluation based on psychoacoustic evaluation amount]
Next, this inventor performed the subjective evaluation by the test subject by the scale composition method based on the psychoacoustic evaluation amount. Here, the scale composition method is, for example, in the case of the evaluation word “free”, as shown in FIG. 9, “not feeling” is set as an evaluation point 0, “slightly low” is set as an evaluation point 2, and “free” Is an evaluation score of 4 and “very gentle” is an evaluation score of 6.

・ We looked at the correlation with the evaluation words when the sharpness was fixed and the loudness was changed (7-30sone).
As a result, as shown in FIG. 10, the loudness is positively correlated with “bulky”, “severe”, and “spread”, and negatively correlated with “soft”, and the sound pressure level ( It was found that the influence of SPL was great.

・ We looked at the correlation with the evaluation words when the sharpness was fixed and the roughness was changed (0.12 to 0.2 asper).
As a result, as shown in FIG. 11, the roughness was negatively correlated with “bulky”, “severe”, and “spread”, and positively correlated with “gentle”.

・ We looked at the correlation with the evaluation words when the loudness was fixed and the fluctuation intensity was changed (0.02 to 0.052 vacil).
As a result, as shown in FIG. 12, the roughness has a negative correlation with “thick” and a positive correlation with “bulky”. Note that there was no correlation between roughness and exhilaration.

・ We looked at the correlation with the evaluation words when the sharpness was fixed and the fluctuation intensity was changed (0.018 to 0.038 vacil).
As a result, as shown in FIG. 13, the fluctuation intensity was negatively correlated with “bulky”, “severe”, and “spread”, and positively correlated with “soft”.

・ We looked at the correlation with the evaluation words when the loudness was fixed and the sharpness was changed (0.8 to 2.5 acum).
As a result, as shown in FIG. 14, the sharpness has a positive correlation with “bulky” and has a negative correlation with “thick”, “exhilarating”, and “spread”. It was.

  From the above, the present inventor shows that when the loudness is fixed, the change in sharpness is correlated with evaluation words related to timbres such as “thick”, “exhilarating”, and “spread”. I caught it. Note that the loudness is a psychoacoustic evaluation amount that represents the loudness of the sound and is excluded because it correlates with the loudness of the sound and is not in terms of the timbre.

  Therefore, the inventor measures the sharpness (acum) value of the product to be evaluated, and, as shown in FIG. 3, an evaluation method using the range of the sharpness value of 1.0 to 1.4 acum as a sound index for psychoacoustic evaluation. I came up with the idea and made it possible to display the results.

[Sound quality evaluation effect of automobile air conditioning sound]
First, when the sound pressure level of the sound source data exceeds 60 dB, the flow proceeds from step S1, step S2, step S3, step S4, step S5, step S9, and end in the flowchart of FIG.

  Therefore, in step S9, for example, the sound pressure level as a mechanical evaluation result is displayed on the display monitor 36, and how much the sound pressure level needs to be reduced from the current state is displayed on the display monitor 36.

  In this case, based on the mechanical evaluation result of the sound pressure level, a change that increases the soundproof performance of the air conditioning unit 5, a change that increases the quietness of the blower fan 6, a change that increases the vibration control performance of the support part of the air conditioning unit 5, etc. Try to improve the sound source. By performing this first stage sound source improvement, the sound pressure level is suppressed to 60 dB or less.

  Next, when the sound pressure level of the sound source data is 60 dB or less, in the flowchart of FIG. 2, step S1, step S2, step S3, step S4, step S5, step S6, step S7, step S8, step S9 in the flowchart of FIG. → The flow goes to the end.

  Therefore, when the vehicle air conditioning sound is evaluated by comparing the calculated sharpness value in step S8 with the selected evaluation sound source data, in step S9, for example, the evaluation sound source data shown in FIG. The calculated sharpness value is overlaid on top. When the sharpness value is between 1.0 acum and 1.4 acum, OK display is performed, and when the sharpness value is other than 1.0 acum to 1.4 acum, NG display is performed. In addition, in the case of OK display, a comment is displayed as to whether or not it is OK with margin or OK, including the amount of deviation from the midpoint of the OK area. In the case of NG display, in order to indicate an improvement target, a deviation amount from the OK range to the higher value side and a deviation amount from the OK range to the lower value side are displayed.

  For this reason, when the sharpness value is other than 1.0 acum to 1.4 acum, the structure of the air conditioning unit 5, the blower fan 6, or the like is changed according to the amount of deviation from the OK region so that the sharpness value is included in the OK region. Try to improve. By performing the sound source improvement in the second stage, the sharpness value is included in 1.0 acum to 1.4 acum.

  That is, in the first embodiment, as shown in FIG. 15, the sound quality evaluation system is based on the relationship between the human sensibility and the evaluation amount using psychoacoustic technology. It is constructed and converted from human sensitivity to evaluation quantity by this sound quality evaluation system. Then, the converted evaluation amount is used as an improvement index of acoustic design, and the mechanical structure is changed based on the evaluation amount. Then, the operation of evaluating the sound quality of the automobile air conditioning sound from the improved sound source by the evaluation amount is repeated again. Here, by selecting the sharpness value as the evaluation amount, the sound quality due to the mechanical sound you are interested in or the sound quality due to the unpleasant mechanical sound is improved, and the sound quality of the sound source is recreated with a pleasant sound that is broad and thick It becomes possible.

Next, the effect will be described.
In the sound quality evaluation method and sound quality evaluation system for automobile air-conditioning sound according to the first embodiment, the effects listed below can be obtained.

  (1) In an air conditioning sound quality evaluation method that quantitatively evaluates the air conditioning sound quality based on the collected air conditioning sound data, an air conditioning sound data sampling procedure (step S3) for collecting air conditioning sound data to be evaluated; A sharpness calculation procedure for drawing a loudness spectrum, which is the volume of sound, from the collected air-conditioning sound data, obtaining a centroid of the spectrum area, and calculating a sharpness that becomes higher as the centroid position is on the higher frequency side (step S6). ), And a sound quality evaluation procedure (step S8) for evaluating the sound quality based on the audibility of the person as to what kind of feeling of air-conditioning sound, using the sharpness value calculated by the sharpness calculation procedure (step S6) as a psychoacoustic evaluation amount, Therefore, it is a simple evaluation method using a single psychoacoustic evaluation amount, but it is a comprehensive air conditioning sound based on human auditory function. It is possible to provide a sound quality evaluation method for air-conditioning sound that appropriately evaluates a sense of comfort.

  (2) In the sound quality evaluation procedure (step S8), when the sharpness value is between 1.0 acum and 1.4 acum, the sharpness value is within the set range in order to evaluate the air conditioning sound with a pleasant sound quality. With only the determination, it is possible to perform a comprehensive evaluation with a high evaluation score for all evaluation words of “thick”, “exhilarating”, and “spread”.

  (3) In a sound quality evaluation system for air conditioning sound that quantitatively evaluates the sound quality of air conditioning sound based on the collected air conditioning sound data, air conditioning sound data collection means (step S3) for collecting air conditioning sound data to be evaluated; Sharpness calculation means for drawing a loudness spectrum as a loudness from the collected air-conditioning sound data, obtaining a centroid of the spectrum area, and calculating a sharpness that is higher as the centroid position is higher on the high frequency side (step S4). ), And a sound quality evaluation means (step S8) for evaluating the sound quality based on the audibility of the person as to what kind of feeling of the air-conditioning sound, using the sharpness value calculated by the sharpness calculation means (step S4) as a psychoacoustic evaluation amount; Therefore, it is a simple evaluation method using one psychoacoustic evaluation amount, but the total of air-conditioning sound based on human auditory function It is possible to provide a sound quality evaluation system for air-conditioning sound that appropriately evaluates a sense of overall comfort.

  (4) The air-conditioning sound is an automobile air-conditioning sound emitted from the air-conditioning unit 5 mounted on the automobile toward the passenger in the passenger compartment, and the air-conditioning sound data collection means (step S3) The sound data is collected at a position corresponding to the left and right ears, and the sharpness calculating means (step S6) is a means for calculating the sharpness from the collected left and right automobile air-conditioning sound data, and the sound quality evaluating means (Step S8) includes the sound thickness and sound spread due to the cross-correlation between the left and right positions in the evaluation, and performs the air conditioning sound evaluation for the sharpness value. Comprehensive evaluation can be performed for evaluation words of “thick” and “expanded”.

  (5) A database 33 for storing and setting a plurality of sound source data for evaluation obtained by performing subjective evaluation by a scale construction method based on sharpness for the evaluation word of the selected air-conditioning sound is provided, and the sound quality evaluation means (step S8) Since the air conditioning sound evaluation is performed by comparing the sharpness value calculated by the sharpness calculation means (step S6) with the evaluation sound source data selected from the database 33, the database 33 can be easily obtained only by an audibility experiment for sharpness. The sharpness can be calculated and the air conditioning sound can be evaluated by simple arithmetic processing and comparison processing.

  (6) The database 33 selects “thick”, “exhilarating”, “spread” as evaluation words suitable for evaluating the air-conditioning sound, and a plurality of acquired evaluation point characteristics for sharpness. The sound source data for evaluation is stored and set, and the sound quality evaluation means (step S8) is an air-conditioned sound with high sound quality having high evaluation scores for all selected evaluation words when the sharpness value is between 1.0 acum and 1.4 acum. All evaluation scores are high for the evaluation words "thick", "exhilarating", and "expanding" simply by determining that the sharpness value is within the range of the setting range. Comprehensive evaluation can be performed.

  (7) Sound pressure level calculation means (step S4) for calculating the sound pressure level of the air conditioning sound from the collected air conditioning sound data, and the sound pressure level of the air conditioning sound calculated by the sound pressure level calculation means (step S4) However, if it exceeds the set sound pressure level that humans feel as noise, a mechanical evaluation is performed with the sound pressure level as a physical quantity, and only when the sound pressure level is equal to or lower than the set sound pressure level, the sound quality evaluation with the sharpness value as the psychoacoustic evaluation quantity Sound pressure level determination means (step S5) for performing vehicle noise reduction by improving the air conditioning sound source based on mechanical evaluation and improving the air conditioning sound source based on sound quality evaluation using the sharpness value as a psychoacoustic evaluation amount. It is possible to improve the vehicle noise with a high evaluation score with respect to the evaluation word suitable for the evaluation.

  (8) The sound pressure level determining means (step S5) obtains a correlation between a rough factor such as “violent”, “bulky”, “soft”, and “turbid” as an evaluation word of the air conditioning sound and a noise level. Since the sound pressure level corresponding to the limit value of the noise level that the impression of the factor is not noticeable for human hearing is determined as the set sound pressure level, air conditioning that keeps the sound pressure level below the set sound pressure level By improving the system, among the evaluation words suitable for evaluating the air conditioning sound of automobiles, it becomes an automobile air conditioning sound that does not care about the rough factors such as “violent”, “bulky”, “soft”, “cloudy” can do.

  As mentioned above, although the sound quality evaluation method and sound quality evaluation system of the air-conditioning sound of this invention have been demonstrated based on Example 1, it is not restricted to this Example 1 about a concrete structure, Each of Claims Additions of methods and changes or additions in system design are permitted without departing from the scope of the claimed invention.

  In the first embodiment, as the air-conditioning sound data collection unit, the example in which the vehicle air-conditioning sound data to be evaluated is collected at a position corresponding to the left and right ears. However, for example, air conditioning sound data may be collected using a single microphone. Further, for example, air conditioning sound data may be collected using three or more microphones.

  In the first embodiment, as an example of the sharpness calculation means, the sharpness value is calculated only when the sound pressure level of the air-conditioning sound calculated by the sound pressure level calculation means is equal to or lower than the set sound pressure level. However, for example, the sharpness may be calculated regardless of the sound pressure level. Further, for example, the mechanical evaluation using the sound pressure level or the like as a physical quantity is performed by another process, and after the mechanical evaluation process is finished, the sound quality evaluation using the sharpness value as a psychoacoustic evaluation quantity may be performed. .

  In the first embodiment, the mechanical evaluation using the sound pressure level as the physical quantity is performed first, and then the sound quality evaluation is performed using the sharpness value as the psychoacoustic evaluation quantity. However, for example, the sound quality evaluation using the sharpness value as the psychoacoustic evaluation amount may be performed first, and then the mechanical evaluation using the sound pressure level as the physical amount may be performed.

  In the first embodiment, as a sound quality evaluation means, by comparing the calculated sharpness value with the evaluation sound source data selected from the database, when the sharpness value is between 1.0 acum and 1.4 acum, An example of air-conditioning sound evaluation is shown. However, for example, the vehicle air conditioning sound may be evaluated finely in a stepless manner or in multiple steps from the optimum value of sharpness.

  In the first embodiment, an example of the sound quality evaluation method and the sound quality evaluation system applied to the sound quality evaluation of the automobile air conditioning sound is shown. The present invention can also be applied to a sound quality evaluation method and a sound quality evaluation system. In short, any air conditioning sound quality evaluation method and sound quality evaluation system that quantitatively evaluates the air quality sound quality based on the collected air conditioning sound data can be applied.

1 is a schematic overall view showing a sound quality evaluation system for automobile air-conditioning sound according to a first embodiment. 4 is a flowchart illustrating a flow of a sound quality evaluation process for automobile air-conditioning sound executed by the personal computer 3 according to the first embodiment. It is a figure which shows an example of the sound source data for evaluation by the evaluation point characteristic of the three evaluation words with respect to the sharpness used in the sound quality evaluation of the vehicle air-conditioning sound of Example 1. This shows the difference in fluctuation between two sound waves with the same sound pressure amplitude but different vibration frequencies. (A) shows an example of sound waves that fluctuate at a frequency of 30 Hz, and (b) shows fluctuations at a frequency of 300 Hz. An example of sound waves when It is a figure which shows an example of 120 evaluation words used in the case of selection by the description selection method of the evaluation word suitable for evaluating a motor vehicle air-conditioning sound. It is a figure which shows the correlation of the rough factor which is one of the factors classified into three by the factor analysis of an evaluation word, and a noise level. It is a figure which shows the correlation of the spatial factor which is one of the factors classified into three by the factor analysis of an evaluation word, and a noise level. It is a figure which shows the correlation of the refreshing factor which is one of the factors classified into three by the factor analysis of an evaluation word, and a noise level. It is a figure which shows the example of a scale structure of the psychoacoustic evaluation with respect to the evaluation word "Adult" used when performing subjective evaluation by the scale structure method based on the psychological sound evaluation amount. It is a figure which shows correlation with the evaluation word at the time of fixing sharpness and changing loudness (7-30 sone). It is a figure which shows correlation with the evaluation word at the time of changing sharpness and changing roughness (0.12-0.2asper). It is a figure which shows the correlation with the evaluation word at the time of changing loudness and changing fluctuation intensity (0.02-0.052vacil). It is a figure which shows correlation with the evaluation word at the time of fixing sharpness and changing fluctuation intensity (0.018-0.038 vacil). It is a figure which shows correlation with an evaluation word at the time of fixing loudness and changing sharpness (0.8-2.5 acum). It is a figure which shows the acoustic design method which improves the sound quality of a sound source from the psychoacoustic evaluation amount using a sound quality evaluation system.

Explanation of symbols

1L left microphone
1R right microphone 2 A / D converter 3 personal computer 31 sound source data storage unit 32 arithmetic processing unit 33 database 34 sound quality evaluation unit 35 display command unit 36 display monitor 37 keyboard 38 computer main body 4 instrument panel 5 air conditioning unit 6 blower fan 7 Central vent outlet 8 Left vent outlet 9 Right vent outlet

Claims (8)

In the sound quality evaluation method for air conditioning sound that quantitatively evaluates the sound quality of the air conditioning sound based on the collected air conditioning sound data,
Air conditioning sound data collection procedure for collecting air conditioning sound data to be evaluated;
From the collected air conditioning sound data, draw a loudness spectrum that is the loudness of the sound, find the center of gravity of the spectrum area, calculate the sharpness that becomes higher as the position of the center of gravity is higher,
A sound quality evaluation procedure for evaluating the sound quality of a person's audibility as to what kind of air conditioning sound is a psychoacoustic evaluation amount, and the sharpness value calculated by the sharpness calculation procedure;
An air quality sound quality evaluation method characterized by comprising: In the sound quality evaluation method of the air-conditioning sound described in claim 1,
The sound quality evaluation procedure is characterized in that when the sharpness value is between 1.0 acum and 1.4 acum, the sound quality is evaluated as a comfortable sound quality air conditioning sound. In the air conditioning sound quality evaluation system that quantitatively evaluates the air conditioning sound quality based on the collected air conditioning sound data,
Air conditioning sound data collection means for collecting air conditioning sound data to be evaluated;
From the collected air conditioning sound data, draw a spectrum of loudness, which is the volume of sound, find the center of gravity of the spectrum area, and sharpness calculation means to calculate the sharpness that becomes higher as the center of gravity position is on the high frequency side,
A sound quality evaluation means for evaluating the sound quality of the person's audibility as to what kind of air conditioning sound is a psychoacoustic evaluation amount using the sharpness value calculated by the sharpness calculation means,
A sound quality evaluation system for air-conditioning sound, characterized by comprising In the sound quality evaluation system for air-conditioning sound according to claim 3,
The air-conditioning sound is an automobile air-conditioning sound that is emitted from an air-conditioning device mounted on the automobile toward the passenger in the passenger compartment.
The air-conditioning sound data collection means is means for collecting the vehicle air-conditioning sound data to be evaluated at a position corresponding to the left and right ears,
The sharpness calculating means is means for calculating sharpness from the collected left and right automobile air conditioning sound data,
The sound quality evaluation means includes a sound thickness and a sound spread due to a cross-correlation between left and right positions in the evaluation, and performs an air conditioning sound evaluation on a sharpness value. In the sound quality evaluation system for an air-conditioning sound according to claim 3 or claim 4,
A database for storing and setting a plurality of sound source data for evaluation obtained by performing subjective evaluation by a scale construction method based on sharpness for the evaluation word of the selected air conditioning sound is provided,
A sound quality evaluation system for air-conditioning sound, wherein the sound quality evaluation means performs air-conditioning sound evaluation by comparing a sharpness value calculated by the sharpness calculation means with an evaluation sound source data selected from the database. In the sound quality evaluation system for air-conditioning sound according to claim 5,
The database selects “thick”, “exhilarating”, and “spread” as evaluation words suitable for evaluating air-conditioning sound, and a plurality of evaluation sound source data acquired as evaluation point characteristics for sharpness Set to remember,
The sound quality evaluation means, when the sharpness value is between 1.0 acum and 1.4 acum, evaluates that the evaluation score of all selected evaluation words is a high-quality air-conditioning sound, Evaluation system. In the sound quality evaluation system for an air-conditioning sound according to any one of claims 3 to 6,
Sound pressure level calculation means for calculating the sound pressure level of the air conditioning sound from the collected air conditioning sound data;
If the sound pressure level of the air-conditioning sound calculated by the sound pressure level calculation means exceeds the set sound pressure level at which a person feels noise, a mechanical evaluation is performed using the sound pressure level as a physical quantity. A sound pressure level determination means for performing sound quality evaluation using a sharpness value as a psychoacoustic evaluation amount only at a certain time,
A sound quality evaluation system for air conditioning sound, characterized by In the sound quality evaluation system of the air-conditioning sound described in claim 7,
The sound pressure level judgment means obtains a correlation between a rough factor such as “severe”, “bulky”, “soft”, and “turbid” as an evaluation word of the air conditioning sound, and the impression of the rough factor is human A sound quality evaluation system for air-conditioning sound, characterized in that a sound pressure level value corresponding to a limit value of a noise level that is unacceptable for hearing is determined as a set sound pressure level.

Images