JPH042299A - Sound quality evaluation device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a sound quality evaluation device used for evaluating audio equipment.

2. Description of the Related Art In recent years, with the advent of CD, DAT, etc., sound quality has been improved by expanding dynamic range, reducing distortion, and flattening frequency characteristics, and minute signal reproduction technology has been developed. At the same time, it has also become important to evaluate the high quality sound reproduced by this technology.

AutoWigner distribution has traditionally been used as a means of evaluating the sound quality of various types of audio equipment, including speakers (e.g., G.N.I.N.S. Vol. 31, No. 4, 19).
1983 (J, A, E, S,, VOL, 31. No.
, 41983)').

FIG. 5 shows an example of conventional evaluation results for speakers. Conventionally, the impulse response of a speaker is captured at a listening point and used to perform autoWigner distribution calculations.

FIG. 5 shows the evaluation results based on the autoWigner distribution of the speaker. The X axis shows frequency, the Y axis shows time, and the Z axis shows power.

Problems to be Solved by the Invention The Wigner distribution described above can accurately distribute signals into instantaneous power values with frequency and time as variables. However, when a Wigner distribution calculation is performed on a signal containing two or more frequencies simultaneously, a cross ring, which is an analysis distortion, is included in the analysis result. As a result, the actually existing signal is affected by the cross ring, making it difficult to evaluate the signal.

In view of the above-mentioned problems, the present invention provides a sound quality evaluation device that calculates and displays power transient response characteristics from an input impulse response signal in a state where cross rings, which are analytical distortions, are further reduced.

Means for Solving the Problems In order to solve the above problems, the sound quality evaluation device of the present invention includes a signal input means for inputting an impulse response from an audio device, and a convolution operation for performing a convolution operation between the input signal and an ideal chirp signal. a Wigner distribution calculation means for calculating a Wigner distribution using the signal obtained by the convolution calculation means; and a Wigner distribution calculation means for calculating a Wigner distribution using the signal obtained by the convolution calculation means; The apparatus is configured to include a time correction calculation means for performing time correction, and a display means for displaying the time correction calculation result in three dimensions of time, frequency, and magnitude.

Effect of the Invention With the above configuration, the present invention convolves the chirb signal with the impulse response to be analyzed and obtains the signal to be analyzed, thereby obtaining the power transient response characteristic with less cross ring, which is analytical distortion, from the input impulse response signal. It becomes possible to analyze and display.

Embodiment Hereinafter, a sound quality evaluation device according to an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 shows a block diagram of a sound quality evaluation device according to a first embodiment of the present invention.

In FIG. 1, 1 is a signal input unit, 2 is a convolution calculation unit, 3 is a Wigner distribution calculation unit, 4 is a time correction calculation unit, and 5
is the display section.

A sound quality evaluation device according to this embodiment configured as follows will be described.

As a mass input signal, a speaker impulse response signal is input into the signal input section 1 in a sampled state. Next, the convolution calculation unit 2 performs a convolution calculation on the impulse response signal taken in by the signal input unit 1 and the chirb signal including up to the frequency to be analyzed, thereby creating a signal for Wigner distribution analysis. Next, in the Wigner distribution calculating section 3, a Wigner distribution, which is a function of time, frequency, and power, indicating the instantaneous power spectrum of the signal is determined from the created analytical signal. The Wigner distribution results obtained in this way are processed in the time correction calculation unit 4 using the time change width Δf of the frequency of the chirb signal used in the convolution calculation unit 2 in the time direction for each frequency. Correct f. The results of the time correction calculation unit 4 are displayed on the display unit 5, with frequency in the χ axis direction, time in the y axis direction, and χ
Measure the size in the axial direction and display it.

FIG. 2 shows the display results of the sound quality evaluation device of the first embodiment. The input signal is the impulse response of the speaker used in the conventional example. It can be seen that the transient response characteristics shown in FIG. 2 are easy to evaluate results with reduced cross rings compared to the conventional transient response characteristics.

FIG. 3 shows a block diagram of a sound quality evaluation device according to a second embodiment of the present invention. In FIG. 3, 1 is a signal input section, 2 is a convolution calculation section, 3 is a lifer distribution calculation section, 4 is a time correction calculation section, and 5 is a display section, which are the same as in the first embodiment. .

The sound quality evaluation device according to this embodiment will be explained based on FIGS. 3 and 4. In FIG. 3, an input unit 1, a convolution calculation unit 2, a Wigner distribution calculation unit 3, a time correction calculation unit 4
Since the operation is similar to that of the first embodiment, detailed explanation thereof will be omitted.

This embodiment differs from the first embodiment in that an integral calculation section 6 is provided, and the following calculations are performed in the integral calculation section 6 on the results obtained by the time correction calculation section 4. Between time 1゛1 and T2 obtained as a result of time correction calculation, every arbitrary interval △
By integrating between the two, a calculation is performed to obtain the cumulative power at time TI+nXΔt for all frequencies, and a cumulative power distribution is obtained. Finally, the result of the integral calculation unit 6 is displayed on the display unit 5, with frequency in the χ axis direction, time in the y axis direction, and χ
Measure and display the size in the axial direction.

FIG. 4 shows the display results of the sound quality evaluation device of the second embodiment. The input signal is the impulse response of the subita used in the conventional example. The power transient response characteristics shown in Figure 4 are:
It represents the attenuation characteristics from the steady state at each frequency. By evaluating this attenuation characteristic, the sound quality evaluation results in the listening experiment can be explained from the physical characteristics.

It can also be seen that the cross ring is further reduced by adding the integral operation.

Although the sound quality evaluation results are displayed in three dimensions in both the first and second embodiments, the magnitude may also be displayed in a two-dimensional contour map, and the correspondence with the axes of time, frequency, and magnitude can also be evaluated. You may choose a display that is easy to read.

Effects of the Invention As described above, the present invention uses a convolution calculation unit, a Wigner distribution calculation unit, a time correction calculation unit, and a display to reduce the cross ring that is a property of the Wigner distribution, and to improve the transient response characteristics of the input power. It is possible to realize a sound quality evaluation device that allows easy evaluation and display based on signals.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a sound quality evaluation device according to a first embodiment of the present invention, FIG. 2 is a diagram showing sound quality evaluation results according to the same embodiment, and FIG. 3 is a diagram showing sound quality evaluation according to a second embodiment of the present invention. FIG. 4 is a block diagram of the apparatus, and FIG. 4 is a diagram showing the sound quality evaluation results according to the same embodiment. FIG. 5 is a diagram showing the conventional sound quality evaluation results for speakers. 1...Signal input unit, 2...Convolution calculation unit, 3...Wigner distribution calculation unit, 4...
... Time correction calculation section, 5 ... Display section, 6 ...
...Integral calculation section. Name of agent: Patent attorney Shigetaka Awano (1 person) Fig. Wl Sis Umata (K?-1z) Fig. 71' Number of holes [ni l-IZI

Claims (2)

[Claims] (1) A signal input means for inputting an impulse response from an audio device, a convolution calculation means for performing a convolution calculation between the input signal and an ideal chirb signal, and a Wigner distribution using the signal obtained by the convolution calculation means. Wigner distribution calculation means; time correction calculation means for time-correcting the results obtained by the Wigner distribution calculation means using time changes in the frequency of the ideal chirb signal; 1. A sound quality evaluation device comprising: display means for displaying in three dimensions. (2) Integral calculation means for integrating the calculation results of the time correction calculation means for each frequency while increasing or decreasing the time width Δt with a certain time as a reference point, and displaying the calculation results by the integration calculation means on a display means. Claim (1)
) Sound quality evaluation device.