JP3686989B2 - Multi-channel conversion synthesizer circuit system - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a multi-channel conversion synthesizer circuit system for generating three-dimensional stereophonic sound from a two-channel stereo input signal in sound reproduction.
[0002]
[Prior art]
There is a three-dimensional (3D) stereo technique as a sense of presence extension means in sound reproduction. In this case, two methods are known as a 3D conversion means.
On the other hand, the applicant of the present application previously proposed a three-dimensional (3D) stereophonic sound generation system by generating a synthesized stereo signal from a single sound source (see Japanese Patent Laid-Open No. 9-284900).
[0003]
[Problems to be solved by the invention]
The appearance of further realistic sound is sought by the cooperation of the 3D stereo enhancement effect and the 3D surround effect according to the above-described conventional technology.
[0004]
[Means for Solving the Problems]
Therefore, in the present invention, after converting a conventional 2-channel stereo (2-channel) system into a three-dimensional (3D) stereo system, this 3D system is combined in parallel, so that 3D2 such as 4 channels, 6 channels, etc. Convert to a channelized stereo system.
[0005]
DETAILED DESCRIPTION OF THE INVENTION
The 3D enhancement method of 3D according to FIG. 1 (a) is characterized by the filter that constitutes it, raises a gain of about 5db around 1Khz as shown in FIG. By passing this circuit, 3D enhancement for a wide area can be realized. The sound image is blurred by increasing the gain near 1 Khz by superimposing two-stage (2 pole) filters on the sound image near 1 Khz by the enhancement of the sound image by the input circuit of RL or RL. And the hollowing out effect can be prevented after enhancement.
[0006]
FIG. 2B shows another method of 3D stereo enhancement. The input part of this system does not have an LR input circuit. The secondary filters are not arranged in two stages as in the method of FIG. 1, but one stage of the secondary filter is arranged in parallel as shown in FIG. At the same time, as shown in FIG. 2 (b), the overall filter characteristics are provided, the filter midrange is lowered by about 5db to 8db in the vicinity of 1Khz, and the hollows are provided so that the rear speaker characteristics can be improved. Emphasizes the surround characteristics against enhancement emphasis.
[0007]
Thus, by combining the front 3D stereo enhancement circuit and the 3D stereo surround circuit in parallel, it is possible to comprehensively expand the characteristics of the 2-channel 3D stereo to the 4-channel 3D surround. This 2-channel / 4-channel conversion system, that is, a synthesizer system, is the gist of the present invention.
[0008]
As shown in FIGS. 4A and 4B, the three-dimensional enhancement surround areas of the 3D 2-channel / 4-channel synthesizer are shown. FIG. 4A shows the case of a 2-channel / 4-channel stereo synthesizer when two speakers are arranged at the front and rear.
[0009]
As shown in FIG. 3, the subwoofer output terminal can be taken out through the sum of R + L, that is, the center speaker output by mono and the low pass filter. Therefore, it is possible to actually realize a 2-channel / 4.1-channel or 5.1-channel synthesizer.
[0010]
The stereo input Basic InR (Pin 36, 37) and Basic InL (Pin 38, 39) inputs can be summed to create an input signal as mono from the stereo inputs L and R, and an input signal for Mono To Stereo can be created. Then, this mono input signal is connected to Pin 22, Cout or bypass terminal Pin 20, CClp as an output through a low-pass filter with SW closed.
[0011]
As a result, a sum circuit signal can be added to the output Pin 26 (FR out) and Pin 25 (FL out) that have passed through the low-pass filter and passed through the Qx stereo 3D enhancement circuit to Pin 21 (Cin). As an example, when a mono signal coming out of Pin 20 is added to Pin 21 (Cin), the signal that has passed through the low-pass filter is a signal output Pin 25 that has undergone Qx3D stereo enhancement Pin 25 and the mono signal that has passed through the low-pass filter that is not 3D stereo enhancement to Pin 26 (70 Hz to 3Khz) can be added onto the 3D stereo enhancement signal.
[0012]
When the stereo original sound is three-dimensionally expanded through the Qx3D stereo enhancement circuit, the spectrum of the original sound in the so-called vocal frequency domain is reduced by the L and R notch filters used. For this reason, when the input stereo original sound is a cheering sound by an audience such as sports broadcasting, for example, baseball, tennis, football, sumo, live stage program, etc., the voice of the announcer etc. is one of the 3D system effects in the vicinity. One feature and a defect in the sound field that is also a defect occurs.
[0013]
Therefore, if Pin20 is connected to Pin21 as a method to improve this nuisance phenomenon that occurs in live broadcasting, etc., the sound of the announcer around 700 to 3 Khz output from Pin25 and Pin26 which are 3D stereo enhancement. Etc. will be lifted without being crushed by the presence of the surroundings, making it easier to hear. As a conclusion, it is possible to prevent a vocal voicing phenomenon in the vocal area due to the 3D stereo enhancement of the stereo input sound, and at the same time, to raise the vocal area having no directionality.
[0014]
When the conventional front 2 channel is made into 3D 2 channel enhancement and paralleled as shown in FIG. 3 and two 2 channel enhancements are arranged like front 2 channel and rear 2 channel, as shown in FIG. Can be made into four channels.
[0015]
In the present invention, the conventional two channels are connected in parallel as described above, so that the number of the four channels or the number of parallels is increased (connected to a plurality of stages), whereby a multi-channel 2n channel can be realized.
[0016]
【The invention's effect】
As described above, according to the present invention, the 3D enhancement technology can be expanded from 2 channels to basically 4 channels (2n channels in terms of expansion). In addition, with this 4-channel stereo, the 3D enhancement 3D sound without hollow is composed by the two front speakers, and the intentionally created 3D surround 3D sound is created by the 2 rear speakers. By synthesizing, 3D enhancement and 3D surround effect are synthesized from each front / rear speaker, and 3D stereo sound such as AC3 (5.1 channel) and Pro Logic (4.1 channel) is created from 2 channels. Can do.
[Brief description of the drawings]
FIG. 1 (a) is a filter configuration diagram showing an example of a three-dimensional sterene enhancement. FIG. 1 (b) is a comprehensive filter characteristic diagram according to the filter configuration. FIG. 2 (a) is another example of a three-dimensional sterene enhancement. Filter configuration diagram [FIG. 2 (b)] Comprehensive filter characteristic diagram based on the above filter configuration [FIG. 3] IC block diagram showing an embodiment of the present invention [FIG. 4 (a)] Three-dimensional enhancement obtained by the system of the present invention FIG. 4B is a diagram showing an example of the surround area. FIG. 4B is a diagram showing another example of the three-dimensional enhancement / surround area obtained by the system of the present invention.
Qx 3D stereo enhancement block Qi 3D stereo surround block

Claims (3)

A 3D stereo enhancement circuit having a filter with the characteristic of raising the gain in the vocal frequency domain for a 2-channel input signal, and a filter with a characteristic of reducing the gain in the frequency domain when connected to the output terminal of the surround signal A multi-channel conversion synthesizer circuit system characterized by connecting a circuit in parallel to obtain a multi-channel output signal. A 3D stereo enhancement circuit having a filter with the characteristic of raising the gain in the vocal frequency domain for a 2-channel input signal, and a filter with a characteristic of reducing the gain in the frequency domain when connected to the output terminal of the surround signal A multi-channel conversion synthesizer circuit system characterized in that a multi-channel output signal is obtained by connecting an appropriate number of circuits in parallel. For a 2-channel input signal, a 3D stereo enhancement circuit having a filter that increases the gain in the vocal frequency domain is used for the front speaker drive circuit, and the output terminal of the surround signal connected in parallel to the circuit is connected to the above frequency. multichannel conversion synthesizer circuit system characterized by using a 3D stereo surround circuit in the rear stereo speaker driving circuit, to obtain a multi-channel output signal having a filter characteristic to reduce the gain region.

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