JP2020184734A - Signal processing device, signal processing method, and speaker device - Google Patents

Abstract

To provide a signal processing device that obtains a volume that does not lose musicality even when the level of an audio signal is limited in order to prevent a breaking sound from a speaker.SOLUTION: A signal processing device executes a first DRC process that compresses an LPF-processed audio signal when an LPF-processed audio signal is a predetermined signal level or more, a second DRC process that compresses the BPF-processed audio signal when the BPF-processed audio signal is a predetermined signal level or more, a third DRC process that compresses the HPF-processed audio signal when the HPF-processed audio signal is a predetermined signal level or more, and a synthesis process that synthesizes the low frequency component of the audio signal and a predetermined frequency band component of the audio signal. In the third DRC process, the signal processing device extends the high cutoff frequency of the BPF process to a high frequency when the HPF processed audio signal is compressed.SELECTED DRAWING: Figure 2

Description

The present invention relates to a signal processing device for processing an audio signal, a signal processing method, and a speaker device including the signal processing device.

There is a speaker with an amplifier (amplifier) (hereinafter referred to as "powered speaker") that amplifies the sound and outputs the amplified sound. In a powered speaker, if a breaking sound is generated from the speaker during loud playback such as maximum volume, it is regarded as a defective product overseas (especially in the United States) and loses its commercial value. Therefore, in a powered speaker, it is essential to perform DRC (Dynamic Range Control) on the audio signal by a signal processing device (for example, DSP (Digital Signal Processor)) so as not to generate a breaking sound (for example, See Patent Document 1).

In a 3-way (woofer, squawker, tweeter) multi-amplifier driven powered speaker, it is common to limit by DRC so that a signal exceeding the withstand input of each unit of the woofer, squawker, and tweeter is not input.

Japanese Unexamined Patent Publication No. 2018-026796

However, when DRC is performed on an audio signal, it tends to be a compressed sound, and the musicality suddenly disappears. Moreover, if it is limited by DRC, it will reach a plateau and the volume cannot be raised.

An object of the present invention is to obtain a volume at which the musicality is not lost even if the level of the audio signal is limited in order to prevent the breaking sound.

The signal processing device of the first invention includes a low-pass filter process for extracting a low-frequency component of an audio signal, a high-pass filter process for extracting a high-frequency component of an audio signal, and a low-frequency component and a high-frequency component of the audio signal. Bandpass filter processing that extracts a predetermined frequency band component between, and first compression that compresses the audio signal that has undergone the lowpass filter processing when the audio signal that has undergone the lowpass filter processing is above the predetermined signal level. The processing, the second compression processing for compressing the audio signal subjected to the bandpass filtering processing when the audio signal subjected to the bandpass filtering processing is equal to or higher than a predetermined signal level, and the highpass filtering processing were performed. When the audio signal is at a predetermined signal level or higher, the third compression process for compressing the high-pass filtered audio signal, the low frequency component of the audio signal, and the predetermined frequency band component of the audio signal are combined. When the audio signal subjected to the high-pass filter processing is compressed in the third compression processing, the high-frequency cutoff frequency of the band-pass filter processing is extended to a high frequency range. ..

In the present invention, in the third compression process, when the audio signal subjected to the high-pass filter process is compressed, the high cutoff frequency of the band-pass filter process is extended to a high frequency range. As a result, if the synthesized audio signal is output to the woofer, the high frequency component is also output from the woofer, so that the sound pressure in the tweeter band can be enhanced. Therefore, in order to prevent the breaking sound, it is possible to obtain a volume that does not lose the musicality even when the level of the audio signal is limited.

The signal processing device of the second invention further performs a low-frequency equalizing process for boosting the low-frequency component of the low-pass filtered audio signal in the signal processing device of the first invention, and in the first compression process. When the audio signal subjected to the low-pass filter is compressed and the audio signal subjected to the high-pass filter processing is compressed in the third compression process, the high cutoff frequency of the bandpass filter process is set to a high frequency. It is characterized in that the low-pass cutoff frequency of the low-pass equalizing process is raised.

In the present invention, a bandpass filter is used when the low-pass filtered audio signal is compressed in the first compression process and the high-pass filtered audio signal is compressed in the third compression process. The high cutoff frequency of the processing is extended to the high frequency, and the low cutoff frequency of the low frequency equalizing processing is raised. As a result, if the synthesized audio signal is output to the woofer, the high frequency component is also output from the woofer, so that the sound pressure in the tweeter band can be increased, and the woofer output is disrupted. Is prevented.

The signal processing device of the third invention is the signal processing device of the second invention, in the case of compressing the voice signal subjected to the bandpass filter processing in the second compression processing, the lowpass filter processing, the band. It is characterized in that the cutoff frequency in the pass filter process, the high pass filter process, and the low cutoff frequency in the low frequency equalizing process are not changed.

The signal processing device of the fourth invention does not compress the audio signal subjected to the bandpass filter processing in the second compression processing in the signal processing device of the first or second invention, and the third In the compression process, when the audio signal subjected to the high-pass filter process is not compressed, the low-pass filter process, the band-pass filter process, and the cutoff frequency in the high-pass filter process are not changed.

In the signal processing device of the fifth invention, in the signal processing device of any one of the first to fourth inventions, the audio signal subjected to the synthesis processing is output to the woofer, and the third compression processing is performed. The audio signal is output to the tweeter.

The signal processing device of the sixth invention includes a low-pass filter process for extracting a low-frequency component of an audio signal, a high-pass filter process for extracting a high-frequency component of an audio signal, and a low-frequency component and a high-frequency component of the audio signal. A first bandpass filter process that extracts a first predetermined frequency band component between, and a second bandpass filter process that extracts a second predetermined frequency band component between a low frequency component and a high frequency component of an audio signal. When the low-pass filtered audio signal is equal to or higher than a predetermined signal level, the first compression process for compressing the low-pass filtered audio signal and the first band-pass filtered audio signal are performed. Is equal to or higher than a predetermined signal level, the second compression process for compressing the audio signal subjected to the first bandpass filter process and the audio signal subjected to the second bandpass filter process are equal to or higher than the predetermined signal level. In the case of, the third compression process of compressing the audio signal subjected to the second bandpass filter process and the high pass filter process when the audio signal subjected to the high pass filter process is equal to or higher than a predetermined signal level. The fourth compression process for compressing the voice signal and the synthesis process for synthesizing the low frequency component of the voice signal and the first predetermined frequency band component of the voice signal are performed, and in the third compression process, When the audio signal subjected to the second bandpass filter processing is compressed, the high frequency cutoff frequency of the first bandpass filter processing is changed to the same value as the high frequency cutoff frequency of the second bandpass filter processing. It is characterized by that.

In the present invention, when the audio signal subjected to the second bandpass filter processing is compressed in the third compression process, the high cutoff frequency of the first bandpass filter process is higher than that of the second bandpass filter process. It is changed to the same value as the cutoff frequency. As a result, if the synthesized audio signal is output to the woofer, the component of the squawker band is also output from the woofer, so that the sound pressure in the squawker band can be enhanced. Therefore, in order to prevent the breaking sound, it is possible to obtain a volume that does not lose the musicality even when the level of the audio signal is limited.

The signal processing device of the seventh invention further performs a low-frequency equalizing process for boosting the low-frequency component of the low-pass filtered audio signal in the signal processing device of the sixth invention, and in the first compression process. When the audio signal subjected to the low-pass filter is compressed and the audio signal subjected to the second high-pass filter process is compressed in the third compression process, the high-frequency cutoff of the first bandpass filter process is performed. It is characterized in that the frequency is changed to the same value as the high cutoff frequency of the second bandpass filter processing, and the low cutoff frequency of the low frequency equalizing processing is raised.

In the present invention, when the audio signal subjected to the low-pass filter processing is compressed in the first compression process and the audio signal subjected to the second bandpass filter processing is compressed in the third compression process. The high cutoff frequency of the first bandpass filter processing is changed to the same value as the high cutoff frequency of the second bandpass filter processing, and the low cutoff frequency of the low frequency equalizing processing is raised. As a result, if the synthesized audio signal is output to the woofer, the component of the squawker band is also output from the woofer, so that the sound pressure in the squawker band can be increased, and the sound pressure of the woofer output can be increased. Bankruptcy is prevented.

The signal processing device of the eighth invention is the signal processing device of the sixth or seventh invention, and when the audio signal subjected to the high-pass filter processing is compressed in the fourth compression processing, the second bandpass It is characterized by extending the high cutoff frequency of the filtering process to the high frequency range.

In the present invention, in the fourth compression process, when the audio signal subjected to the high-pass filter process is compressed, the high cutoff frequency of the second band-pass filter process is extended to a high frequency range. As a result, if the audio signal subjected to the second bandpass filter processing is output from the squawker, the tweeter band component is output from the squawker, so that the sound pressure in the tweeter band can be enhanced.

The signal processing apparatus of the ninth invention compresses the audio signal subjected to the second bandpass filter processing in the third compression processing in the signal processing apparatus of any of the sixth to eighth inventions, and In the fourth compression process, when the audio signal subjected to the high-pass filter process is compressed, the high cutoff frequency of the first bandpass filter process and the low cutoff frequency of the second bandpass filter process are set. It is characterized by shifting to a high range and shifting the high cutoff frequency of the second bandpass filter processing to a high range.

In the present invention, when the audio signal subjected to the second bandpass filter processing is compressed in the third compression process and the audio signal subjected to the high pass filter processing is compressed in the fourth compression process. The high cutoff frequency of the first bandpass filter processing and the low cutoff frequency of the second bandpass filter processing are shifted to high frequencies, and the high cutoff frequency of the second bandpass filter processing is shifted to high frequencies. To. As a result, if the synthesized audio signal is output to the woofer, the component of the squawker band is supplemented by the woofer, and the squawker is prevented from breaking down. Further, if the audio signal subjected to the second bandpass filter processing is output from the squawker, the tweeter band component is output from the squawker, so that the sound pressure in the tweeter band can be enhanced.

The signal processing apparatus of the tenth invention is the signal processing apparatus of the seventh invention, in the case of compressing the audio signal subjected to the first bandpass filter processing in the second compression processing, the first bandpass filter. It is characterized in that the cutoff frequency of the processing and the low cutoff frequency of the low frequency equalizing processing are not changed.

The signal processing device of the eleventh invention compresses the audio signal subjected to the first bandpass filter processing in the second compression processing in the signal processing device of any one of the sixth to tenth inventions, and the above-mentioned. When the audio signal subjected to the second bandpass filter processing is compressed in the third compression process and the audio signal subjected to the highpass filter process is compressed in the fourth compression process, the lowpass filter process is performed. , The first bandpass filter process, the second bandpass filter process, and the high pass filter process do not change the cutoff frequency.

In the signal processing device of the twelfth invention, in the signal processing device of any one of the sixth to eleventh inventions, the audio signal subjected to the synthesis processing is output to the woofer, and the third compression processing is performed. The audio signal is output to the scoker, and the audio signal subjected to the fourth compression process is output to the tweeter.

The signal processing apparatus of the thirteenth invention includes a first volume processing that attenuates an audio signal based on a received volume value, a low-pass filter processing that extracts a low-frequency component of the audio signal, and a high-frequency component of the audio signal. High-pass filter processing to extract, band-pass filter processing to extract a predetermined frequency band component between the low-frequency component and the high-frequency component of the audio signal, the low-frequency component of the audio signal, and the predetermined frequency band component of the audio signal. When the volume value in the first volume processing is equal to or greater than a predetermined value, the high cutoff frequency of the bandpass filter processing is extended to a high frequency range. ..

In the present invention, when the volume value in the first volume processing is equal to or higher than a predetermined value, the high cutoff frequency of the bandpass filter processing is extended to a high frequency range. As a result, if the synthesized audio signal is output to the woofer, the high frequency component is also output from the woofer, so that the maximum volume can be obtained.

The signal processing device of the fourteenth invention further performs a low-frequency equalizing process for boosting a low-frequency component of the low-pass filtered audio signal in the signal processing device of the thirteenth invention, and in the first volume process. When the volume value is equal to or higher than a predetermined value, the low-pass cutoff frequency of the low-pass equalizing process is increased.

The signal processing apparatus of the fifteenth invention is the signal processing apparatus of the fourteenth invention, in which the high cutoff frequency of the bandpass filter processing and the high cutoff frequency of the bandpass filter processing are performed when the volume value in the first volume processing is not equal to or more than a predetermined value. It is characterized in that the low cutoff frequency of the low frequency equalizing process is not changed.

The signal processing device of the sixteenth invention is the signal processing device of any one of the thirteenth to fifteenth inventions, in which the low-pass filter processing is performed when the voice signal subjected to the low-pass filter processing is at a predetermined signal level or higher. The first compression process for compressing the voice signal that has been subjected to the bandpass filter processing, and the second compression process for compressing the voice signal that has undergone the bandpass filter processing when the sound signal that has undergone the bandpass filter processing is at a predetermined signal level or higher. The compression process and the third compression process of compressing the high-pass filter-processed audio signal when the high-pass filter-processed audio signal is at a predetermined signal level or higher are further performed, and the third compression process is performed. In the processing, when the audio signal subjected to the high-pass filter processing is compressed, the high-frequency cutoff frequency of the band-pass filter processing is extended to a high region.

The signal processing device of the seventeenth invention further performs a low-frequency equalizing process for boosting a low-frequency component of the low-pass filtered audio signal in the signal processing device of the sixteenth invention, and in the first compression process. When the audio signal subjected to the low-pass filter is compressed and the audio signal subjected to the high-pass filter processing is compressed in the third compression process, the high cutoff frequency of the bandpass filter process is set to a high frequency. It is characterized in that the low-pass cutoff frequency of the low-pass equalizing process is raised.

The signal processing apparatus of the eighteenth invention is the signal processing apparatus of the seventeenth invention, in the case of compressing the voice signal subjected to the bandpass filter processing in the second compression processing, the lowpass filter processing and the band. It is characterized in that the cutoff frequency in the pass filter process, the high pass filter process, and the low cutoff frequency in the low frequency equalizing process are not changed.

The signal processing apparatus of the nineteenth invention does not compress the audio signal subjected to the bandpass filter processing in the second compression processing in the signal processing apparatus of the sixteenth or seventeenth invention, and the third. In the compression process, when the audio signal subjected to the high-pass filter process is not compressed, the low-pass filter process, the band-pass filter process, and the cutoff frequency in the high-pass filter process are not changed.

In the signal processing device of the twentieth invention, the audio signal subjected to the synthesis processing is output to the woofer in the signal processing device of any one of the thirteenth to nineteenth inventions, and the third compression processing is performed. The audio signal is output to the tweeter.

The signal processing device of the twenty-first invention includes a first volume processing that attenuates an audio signal based on a received volume value, a low-pass filter processing that extracts a low-frequency component of the audio signal, and a high-frequency component of the audio signal. High-pass filter processing to extract, first band-pass filter processing to extract the first predetermined frequency band component between the low-frequency component and high-frequency component of the audio signal, and the low-frequency component and high-frequency component of the audio signal. A second bandpass filter process for extracting the second predetermined frequency band component between the two is performed, and a synthesis process for synthesizing the low frequency component of the audio signal and the first predetermined frequency band component of the audio signal is performed. When the volume value in the first volume processing is equal to or higher than a predetermined value, the high cutoff frequency of the first bandpass filter processing is changed to the same value as the high cutoff frequency of the second bandpass filter processing. It is a feature.

In the present invention, when the volume value in the first volume processing is equal to or higher than a predetermined value, the high cutoff frequency of the first bandpass filter processing is changed to the same value as the high cutoff frequency of the second bandpass filter processing. Will be done. As a result, if the synthesized audio signal is output to the woofer, the component of the squawker band is also output from the woofer, so that the maximum volume can be obtained.

In the signal processing apparatus of the 21st invention, the signal processing apparatus of the 22nd invention sets the high cutoff frequency of the 2nd bandpass filter processing when the volume value in the 1st volume processing is equal to or higher than a predetermined value. It is characterized by extending to high frequencies.

The signal processing device of the 23rd invention further performs a low-frequency equalizing process for boosting the low-frequency component of the low-pass filtered audio signal in the signal processing device of the 21st or 22nd invention, and the first When the volume value in the volume processing is equal to or higher than a predetermined value, the low cutoff frequency of the low frequency equalizing processing is increased.

In the signal processing device of the 23rd invention, the signal processing device of the 24th invention is the height of the first bandpass filter processing and the second bandpass filter when the volume value in the first volume value is not equal to or more than a predetermined value. It is characterized in that the region cutoff frequency and the low region cutoff frequency of the low frequency equalizing process are not changed.

The signal processing device of the 25th invention is the signal processing device of any of the 21st to 24th inventions, when the voice signal subjected to the low-pass filter processing is equal to or higher than a predetermined signal level, the low-pass filter processing is performed. When the first compression process for compressing the voice signal subjected to the above and the voice signal subjected to the first bandpass filter processing is equal to or higher than a predetermined signal level, the voice signal subjected to the first bandpass filter processing is subjected to. The second compression process for compressing and the third compression process for compressing the audio signal subjected to the second bandpass filter process when the audio signal subjected to the second bandpass filter process is equal to or higher than a predetermined signal level. And the fourth compression process of compressing the audio signal subjected to the high-pass filter process when the audio signal subjected to the high-pass filter process is equal to or higher than a predetermined signal level, and in the third compression process. , When the audio signal subjected to the second bandpass filter processing is compressed, the high frequency cutoff frequency of the first bandpass filter processing is changed to the same value as the high frequency cutoff frequency of the second bandpass filter processing. It is characterized by doing.

The signal processing apparatus of the 26th invention further performs a low-frequency equalizing process for boosting the low-frequency component of the low-pass filtered audio signal in the signal processing apparatus of the 25th invention, and in the first compression process. When the audio signal subjected to the low-pass filter is compressed and the audio signal subjected to the second high-pass filter process is compressed in the third compression process, the high-frequency cutoff of the first bandpass filter process is performed. It is characterized in that the frequency is changed to the same value as the high cutoff frequency of the second bandpass filter processing, and the low cutoff frequency of the low frequency equalizing processing is raised.

The signal processing device of the 27th invention is the signal processing device of the 25th or 26th invention, in the case of compressing the audio signal subjected to the high-pass filter processing in the fourth compression processing, the second bandpass. It is characterized by extending the high cutoff frequency of the filtering process to the high frequency range.

The signal processing apparatus of the 28th invention compresses the audio signal subjected to the second bandpass filter processing in the third compression processing in the signal processing apparatus of any of the 25th to 27th inventions, and In the fourth compression process, when the audio signal subjected to the high-pass filter process is compressed, the high cutoff frequency of the first bandpass filter process and the low cutoff frequency of the second bandpass filter process are set. It is characterized by shifting to a high range and extending the high cutoff frequency of the second bandpass filter processing to a high range.

The signal processing apparatus of the 29th invention is a signal processing apparatus of the 26th invention, in the case of compressing the audio signal subjected to the first bandpass filter processing in the second compression processing, the first bandpass filter. It is characterized in that the cutoff frequency of the processing and the low cutoff frequency of the low frequency equalizing processing are not changed.

The signal processing apparatus according to the thirtieth invention compresses the audio signal subjected to the first bandpass filter processing in the second compression processing in the signal processing apparatus according to any one of the 25th to 29th inventions. When the audio signal subjected to the second bandpass filter processing is compressed in the third compression process and the audio signal subjected to the highpass filter process is compressed in the fourth compression process, the lowpass filter process is performed. , The first bandpass filter process, the second bandpass filter process, and the high pass filter process do not change the cutoff frequency.

In the signal processing device of the thirty-first invention, the audio signal subjected to the synthesis processing is output to the woofer in the signal processing device of any one of the twenty-first to thirtieth inventions, and the third compression processing is performed. The audio signal is output to the scoker, and the audio signal subjected to the fourth compression process is output to the tweeter.

The speaker device of the thirty-second invention is characterized by including a signal processing device according to any one of the first to third aspects and a speaker into which an audio signal from the signal processing device is input.

The signal processing method of the 33rd invention includes low-pass filter processing for extracting low-pass components of an audio signal, high-pass filter processing for extracting high-pass components of an audio signal, and low-pass and high-frequency components of an audio signal. A bandpass filter process that extracts a predetermined frequency band component between them, and a first compression that compresses the low-pass filter-processed audio signal when the low-pass filter-processed audio signal is at a predetermined signal level or higher. The processing, the second compression processing for compressing the audio signal subjected to the bandpass filtering processing when the audio signal subjected to the bandpass filtering processing is equal to or higher than a predetermined signal level, and the high-pass filtering processing were performed. When the audio signal is equal to or higher than a predetermined signal level, a third compression process for compressing the audio signal subjected to the high-pass filter processing is performed, and the first compression process, the second compression process, and the third compression are performed. In any of the processes, when the audio signal is compressed, the cutoff frequencies of the low-pass filter process, the band-pass filter process, and the high-pass filter process are changed.

In the present invention, when the audio signal is compressed in any of the first compression process, the second compression process, and the third compression process, the cutoff frequencies of the low-pass filter process, the band-pass filter process, and the high-pass filter process are changed. To. As a result, the audio signal components output to the speaker unit have overlapping bands, so that the number of units to be reproduced increases and the maximum volume can be increased.

The signal processing method of the 34th invention includes a low-pass filter process for extracting a low-frequency component of an audio signal, a high-pass filter process for extracting a high-frequency component of an audio signal, and a low-frequency component and a high-frequency component of the audio signal. A bandpass filter process that extracts a predetermined frequency band component between them, and a first compression that compresses the lowpass filtered audio signal when the lowpass filtered audio signal is at a predetermined signal level or higher. The processing, the second compression processing for compressing the audio signal subjected to the bandpass filtering processing when the audio signal subjected to the bandpass filtering processing is equal to or higher than a predetermined signal level, and the high-pass filtering processing were performed. When the audio signal is at a predetermined signal level or higher, the third compression process for compressing the high-pass filtered audio signal, the low frequency component of the audio signal, and the predetermined frequency band component of the audio signal are combined. When the audio signal subjected to the high-pass filter processing is compressed in the third compression processing, the high-frequency cutoff frequency of the band-pass filter processing is extended to a high frequency range. ..

The signal processing method of the 35th invention includes a low-pass filter process for extracting a low-frequency component of an audio signal, a high-pass filter process for extracting a high-frequency component of an audio signal, and a low-frequency component and a high-frequency component of the audio signal. A first bandpass filter process that extracts a first predetermined frequency band component between, and a second bandpass filter process that extracts a second predetermined frequency band component between a low frequency component and a high frequency component of an audio signal. When the low-pass filtered audio signal is equal to or higher than a predetermined signal level, the first compression process for compressing the low-pass filtered audio signal and the first band-pass filtered audio signal are performed. Is equal to or higher than a predetermined signal level, the second compression process for compressing the audio signal subjected to the first bandpass filter process and the audio signal subjected to the second bandpass filter process are equal to or higher than the predetermined signal level. In the case of, the third compression process of compressing the audio signal subjected to the second bandpass filter process and the high pass filter process when the audio signal subjected to the high pass filter process is equal to or higher than a predetermined signal level. The fourth compression process for compressing the voice signal and the synthesis process for synthesizing the low frequency component of the voice signal and the first predetermined frequency band component of the voice signal are performed, and in the third compression process, When the audio signal subjected to the second bandpass filter processing is compressed, the high frequency cutoff frequency of the first bandpass filter processing is changed to the same value as the high frequency cutoff frequency of the second bandpass filter processing. It is characterized by that.

The signal processing method of the 36th invention includes a first volume processing that attenuates an audio signal based on a received volume value, a low-pass filter processing that extracts a low-frequency component of the audio signal, and a high-frequency component of the audio signal. High-pass filter processing to extract, band-pass filter processing to extract a predetermined frequency band component between the low-frequency component and the high-frequency component of the audio signal, the low-frequency component of the audio signal, and the predetermined frequency band component of the audio signal. When the volume value in the first volume processing is equal to or greater than a predetermined value, the high cutoff frequency of the bandpass filter processing is extended to a high frequency range. ..

The signal processing method of the 37th invention includes a first volume processing that attenuates an audio signal based on a received volume value, a low-pass filter processing that extracts a low-frequency component of an audio signal, and a high-frequency component of an audio signal. High-pass filter processing to extract, first band-pass filter processing to extract the first predetermined frequency band component between the low-frequency component and high-frequency component of the audio signal, and the low-frequency component and high-frequency component of the audio signal. A second bandpass filter process for extracting the second predetermined frequency band component between the two is performed, and a synthesis process for synthesizing the low frequency component of the audio signal and the first predetermined frequency band component of the audio signal is performed. When the volume value in the first volume processing is equal to or higher than a predetermined value, the high cutoff frequency of the first bandpass filter processing is changed to the same value as the high cutoff frequency of the second bandpass filter processing. It is a feature.

The signal processing method of the 38th invention includes low-pass filter processing for extracting low-pass components of an audio signal, high-pass filter processing for extracting high-pass components of an audio signal, and low-pass and high-pass components of an audio signal. A bandpass filter process that extracts a predetermined frequency band component between them, and a first compression that compresses the low-pass filter-processed audio signal when the low-pass filter-processed audio signal is at a predetermined signal level or higher. The processing, the second compression processing for compressing the audio signal subjected to the bandpass filtering processing when the audio signal subjected to the bandpass filtering processing is equal to or higher than a predetermined signal level, and the high-pass filtering processing were performed. When the audio signal is at or above a predetermined signal level, a third compression process for compressing the high-pass filtered audio signal is performed, and the first compression process, the second compression process, and the third compression are performed. In any of the processes, when the audio signal is compressed, the cutoff frequencies of the low-pass filter process, the band-pass filter process, and the high-pass filter process are changed.

According to the present invention, in order to prevent the breaking sound, it is possible to obtain a volume that does not lose the musicality even when the level of the audio signal is limited.

It is a block diagram which shows the structure of the speaker apparatus which concerns on embodiment of this invention. It is a figure which shows the signal processing by DSP in 1st Embodiment. It is a figure which shows the frequency band which is output to a speaker unit. It is a flowchart which shows the processing operation of the DSP which concerns on 1st Embodiment. It is a figure which shows the signal processing by DSP in 2nd Embodiment. It is a figure which shows the frequency band which is output to a speaker unit. It is a flowchart which shows the processing operation of DSP which concerns on 2nd Embodiment. It is a flowchart which shows the processing operation of DSP which concerns on 2nd Embodiment.

Hereinafter, embodiments of the present invention will be described. FIG. 1 is a diagram showing a speaker device according to an embodiment of the present invention. The speaker device 1 includes a microcomputer 2, an operation unit 3, a DSP (Digital Signal Processor) 4, a D / A converter (hereinafter referred to as “DAC”) 5, an amplifier 6, a speaker 7, and a wireless module. 8 and.

The microcomputer 2 controls each part constituting the speaker device 1. The operation unit 3 has operation keys and the like for receiving various settings. The operation unit 3 has, for example, a volume knob for receiving a volume adjustment by the user. DSP4 (signal processing device) performs signal processing on a digital audio signal. The signal processing performed by DSP4 will be described later. The DAC 5 D / A-converts the digital audio signal processed by the DSP 4 into an analog audio signal. The amplifier 6 amplifies the analog audio signal D / A-converted by the DAC 5. The analog audio signal amplified by the amplifier 6 is output to the speaker 7. The speaker 7 outputs audio based on the input analog audio signal. The wireless module 8 is for performing wireless communication in accordance with the Bluetooth (registered trademark) standard and the Wi-Fi standard.

The microcomputer 2 receives, for example, a digital audio signal transmitted from a smartphone, a digital audio player, or the like via the wireless module 10. Then, the microcomputer 2 causes the received digital audio signal to perform signal processing by the DSP 4.

(First Embodiment)
In the first embodiment, the speaker 7 is a 2-way speaker including a tweeter and a woofer. FIG. 2 is a diagram showing signal processing by DSP4 in the first embodiment. The DSP4 includes speaker adjustment equalizing processing (hereinafter referred to as “speaker adjustment EQ processing”), low-pass filter processing (hereinafter referred to as “LPF processing”), low-frequency equalizing processing (hereinafter referred to as low-frequency EQ processing), and attenuation. Processing, first dynamic range control processing (hereinafter, "dynamic range control processing" is referred to as "DRC processing"), second DRC processing, third DRC processing, bandpass filter processing (hereinafter, "BPF processing") high-pass filter Processing (hereinafter, referred to as "HPF processing"), first volume processing, second volume processing, and synthesis processing are performed.

The speaker adjustment EQ process is a process of adjusting the frequency characteristics of an audio signal according to the characteristics of the speaker. The DSP4 performs speaker adjustment EQ processing on the input audio signal. The LPF process is a process for extracting a low frequency component of an audio signal. The DSP4 performs LPF processing on the audio signal subjected to the speaker adjustment EQ processing. The BPF process is to extract a predetermined frequency band component between the low frequency component and the high frequency component. The DSP4 performs BPF processing on the audio signal that has undergone speaker adjustment EQ processing. The HPF process is a process for extracting a high frequency component of an audio signal. The DSP4 performs HPF processing on the audio signal that has undergone speaker adjustment EQ processing. The low-frequency EQ process is a process for boosting the low-frequency component of an audio signal. The DSP4 performs low-pass EQ processing on the LPF-processed audio signal.

The first volume processing is a processing for attenuating an audio signal based on a volume value received by the microcomputer 2. The DSP4 performs the first volume processing on the low frequency component of the audio signal subjected to the low frequency EQ processing, the predetermined frequency band component of the audio signal subjected to the BPF processing, and the high frequency component of the audio signal subjected to the HPF processing. Therefore, the first volume processing is performed on all band components of the audio signal output to the speaker 7. The first volume corresponds to a so-called master volume. The microcomputer 2 receives the instruction of the volume value by the user via the operation unit 3. The frequency extracted by the LPF process is preferably set so as to include the minimum resonance frequency f0 or less of the speaker.

The attenuation process is a process for attenuating an audio signal. The DSP4 performs attenuation processing on the audio signal of the low frequency component that has undergone the first volume processing. The first DRC process (first compression process) is a process of compressing an audio signal when the audio signal is at a predetermined signal level or higher. The DSP4 performs the first DRC processing on the audio signal that has undergone the low-frequency EQ processing.

The second volume process is a process of attenuating the audio signal based on the volume value received by the microcomputer 2. The DSP4 performs a second volume process on the BPF-processed audio signal and the HPF-processed audio signal. The second DRC process (second compression process) is a process of compressing an audio signal when the audio signal is at a predetermined signal level or higher. The DSP4 performs the second DRC processing on the predetermined frequency band component of the audio signal subjected to the second volume processing. The synthesizing process is a process of synthesizing the audio signal subjected to the first DRC process and the audio signal subjected to the second DRC process. The DSP4 performs a synthesis process on the audio signal subjected to the first DRC processing and the audio signal subjected to the second DRC processing. The audio signal after the synthesis processing is output to the woofer.

The third DRC process (third compression process) is a process of compressing an audio signal when the audio signal is at a predetermined signal level or higher. DSP4 performs the third DRC processing on the high region component of the audio signal which performed the second volume processing. The audio signal subjected to the third DRC processing is output to the tweeter.

In the present embodiment, the DSP4 limits the level of the audio signal by the DRC processing in order to prevent the cutoff sound, but whether or not the audio signal is compressed in the DRC processing in order to obtain a volume that does not lose the musicality. The high cutoff frequency of the BPF processing and the low cutoff frequency of the low EQ processing are changed based on the above.

FIG. 3 is a diagram showing a frequency band output to the speaker unit (woofer, tweeter). The horizontal axis shows the frequency, and the vertical axis shows the level of the voice signal. In the original frequency control, the signal of the frequency band shown by the solid line is output to the woofer and the tweeter.

The DSP4 compresses the HPF-processed audio signal in the third DRC process and does not compress the LPF-processed audio signal in the first DRC process, as shown in FIG. 3 (1). The high cutoff frequency of BPF processing is extended to high frequencies. For example, DSP4 changes the high cutoff frequency of BPF processing to the frequency indicated by the broken line. Further, when the DSP4 compresses the audio signal subjected to the HPF processing in the third DRC processing and compresses the audio signal subjected to the LPF processing in the first DRC processing, as shown in FIG. 3 (1). In addition, the high cutoff frequency of the BPF processing is extended to the high frequency, and the low cutoff frequency of the low frequency EQ processing is raised as shown in (2) of FIG.

The DSP4 maintains the original frequency control when compressing the BPF-processed audio signal in the second DRC process. That is, DSP4 does not change the high cutoff frequency of the BPF processing and the low cutoff frequency of the low EQ processing.

FIG. 4 is a flowchart showing the processing operation of the DSP 4 according to the first embodiment. DSP4 determines whether or not the second DRC process is on (S1). Here, "DRC processing is on" means that the voice signal is at a predetermined level or higher and the DRC processing is executed. When the DSP4 determines that the second DRC process is not on (S1: No), the DSP4 determines whether or not the third DRC process is on (S2). The DSP4 maintains the original frequency control when it is determined that the third DRC process is not on (S2: No) or when it is determined that the second DRC process is on (S1: Yes).

When the DSP4 determines that the third DRC process is on (S2: Yes), the DSP4 determines whether or not the first DRC process is on (S4). When the DSP4 determines that the first DRC process is not on (S4: No), the DSP4 extends the high cutoff frequency of the BPF process to a high frequency range (S5). On the other hand, when it is determined that the first DRC processing is on (S4: Yes), the DSP4 raises the low cutoff frequency of the low frequency EQ and extends the high cutoff frequency of the BPF processing to the high frequency band (S6).
The DSP4 executes the process of S1 after the process of S3, S5, or S6.

As described above, in the present embodiment, when the audio signal subjected to the HPF processing is compressed in the third DRC processing, the high cutoff frequency of the BPF processing is extended to a high frequency. As a result, the high frequency component is also output from the woofer, so that the sound pressure in the tweeter band can be enhanced. Therefore, in order to prevent the breaking sound, it is possible to obtain a volume that does not lose the musicality even when the level of the audio signal is limited.

Further, in the present embodiment, when the audio signal subjected to the LPF processing is compressed in the first DRC processing and the audio signal subjected to the HPF processing is compressed in the third DRC processing, the BPF processing is high. The region cutoff frequency is extended to the high region, and the low region cutoff frequency of the low frequency EQ processing is raised. As a result, since the high frequency component is also output from the woofer, the sound pressure in the tweeter band can be increased, and the woofer output is prevented from collapsing.

(Second Embodiment)
In the second embodiment, the speaker 7 is a 3-way speaker including a tweeter, a squawker, and a woofer. Hereinafter, the same processing as that of the first embodiment will be omitted as appropriate. FIG. 5 is a diagram showing signal processing by DSP4 in the second embodiment. The DSP4 has speaker adjustment EQ processing, LPF processing, and low-pass EQ processing, which are attenuation processing, first DRC processing, second DRC processing, third DRC processing, fourth DRC processing, first BPF processing, second BPF processing, HPF processing, and first volume. Performs processing, second volume processing, and composition processing.

The DSP4 performs speaker adjustment EQ processing on the input audio signal. The LPF process is a process for extracting a low frequency component of an audio signal. The DSP4 performs LPF processing on the audio signal subjected to the speaker adjustment EQ processing. The first BPF process is a process for extracting a predetermined frequency band component between the low frequency component and the high frequency component. The DSP4 performs the first BPF processing on the audio signal that has undergone the speaker adjustment EQ processing. The second BPF process is a process of extracting a predetermined frequency component (a process of extracting) between the low frequency component and the high frequency component. The DSP4 performs the second BPF process on the audio signal subjected to the speaker adjustment EQ process. The HPF process is It is a process of extracting a high frequency component of an audio signal. DSP4 performs HPF processing on an audio signal subjected to speaker adjustment EQ processing. DSP 4 performs low frequency EQ processing on an audio signal subjected to LPF processing.

DSP4 performed the low frequency component of the audio signal subjected to the low frequency EQ processing, the predetermined frequency band component of the audio signal subjected to the first BPF processing, the predetermined frequency band component of the audio signal subjected to the second BPF processing, and the HPF processing. The first volume processing is performed on the high frequency component of the audio signal. Therefore, the first volume processing is performed on all band components of the audio signal output to the speaker 7. The first volume corresponds to a so-called master volume. The microcomputer 2 receives the instruction of the volume value by the user via the operation unit 3. The frequency extracted by the LPF process is preferably set so as to include the minimum resonance frequency f0 or less of the speaker.

The attenuation process is a process for attenuating an audio signal. The DSP4 performs attenuation processing on the audio signal of the low frequency component that has undergone the first volume processing. The first DRC process (first compression process) is a process of compressing an audio signal when the audio signal is at a predetermined signal level or higher. The DSP4 performs the first DRC processing on the audio signal that has undergone the low-frequency EQ processing.

The second volume process is a process of attenuating the audio signal based on the volume value received by the microcomputer 2. The DSP4 performs the second volume processing on the audio signal subjected to the first BPF processing, the audio signal subjected to the second BPF processing, and the audio signal subjected to the HPF processing. The second DRC process (second compression process) is a process of compressing an audio signal when the audio signal is at a predetermined signal level or higher. The DSP4 performs the second DRC processing on the predetermined frequency band component of the audio signal subjected to the second volume processing. The synthesizing process is a process of synthesizing the audio signal subjected to the first DRC process and the audio signal subjected to the second DRC process. The DSP4 performs a synthesis process on the audio signal subjected to the first DRC processing and the audio signal subjected to the second DRC processing. The audio signal after the synthesis processing is output to the woofer.

The third DRC process (third compression process) is a process of compressing an audio signal when the audio signal is at a predetermined signal level or higher. The DSP4 performs a third DRC process on a predetermined frequency band component of the audio signal that has undergone the second volume process. The audio signal subjected to the third DRC processing is output to the squawker. The fourth DRC process (fourth compression process) is a process of compressing an audio signal when the audio signal is at a predetermined signal level or higher. DSP4 performs the fourth DRC processing on the high region component of the audio signal which performed the second volume processing. The audio signal subjected to the fourth DRC processing is output to the tweeter.

FIG. 6 is a diagram showing a frequency band output to the speaker unit (woofer, squawker, tweeter). The horizontal axis shows the frequency, and the vertical axis shows the level of the voice signal. In the original frequency control, the signal of the frequency band shown by the solid line is output to the woofer, the squawker, and the tweeter.

DSP4 is shown in FIGS. 6 (a) and 6 (1) when the audio signal subjected to the second BPF process is compressed in the third DRC process and the audio signal subjected to the LPF process is not compressed in the first DRC process. As described above, the high cutoff frequency of the first BPF processing is changed to the same value as the high cutoff frequency of the second BPF processing. The DSP4 is shown in FIGS. 6 (a) and 6 (1) when the audio signal subjected to the second BPF process is compressed in the third DRC process and the audio signal subjected to the LPF process is compressed in the first DRC process. As described above, the high cutoff frequency of the first BPF processing is changed to the same value as the high cutoff frequency of the second BPF processing, and as shown in FIGS. 6A and 6A, the low cutoff frequency of the low EQ processing is changed. Raise.

The DSP4 is shown in FIGS. 6 (b) and 6 (3) when the audio signal subjected to the HPF processing is compressed in the 4th DRC processing and the audio signal subjected to the 2nd BPF processing is not compressed in the 3rd DRC processing. As described above, the high cutoff frequency of the second BPF processing is extended to the high frequency range. The DSP4 compresses the audio signal subjected to the HPF processing in the fourth DRC processing, compresses the audio signal subjected to the second BPF processing in the third DRC processing, and performs the first BPF processing in the second DRC processing. When the audio signal is not compressed, as shown in FIGS. 6 (b) and 6 (4), the high cutoff frequency of the first BPF processing and the low cutoff frequency of the second BPF processing are shifted to high frequencies, and FIG. b) As shown in (3), the high cutoff frequency of the second BPF processing is shifted to the high frequency.

The DSP4 maintains the original frequency control in the first BPF processing and the low frequency EQ processing when the audio signal subjected to the first BPF processing is compressed in the second DRC processing. That is, DSP4 does not change the cutoff frequency of the first BPF processing and the low cutoff frequency of the low-frequency EQ processing.

The DSP4 compresses the audio signal subjected to the HPF processing in the fourth DRC processing, compresses the audio signal subjected to the second BPF processing in the third DR processing, and performs the first BPF processing in the second DRC processing. Maintain original frequency control when compressing the signal. That is, DSP4 does not change the cutoff frequency of LPF processing, first BPF processing, second BPF processing, HPF processing, and low frequency cutoff frequency of low frequency EQ processing.

7 and 8 are flowcharts showing the processing operation of the DSP 4 according to the second embodiment. DSP4 determines whether or not the second DRC process is on (S11). When the DSP4 determines that the second DRC process is on (S11: Yes), the DSP4 determines whether or not the third DRC process is on (S12). When the DSP4 determines that the third DRC process is on (S12: Yes), the DSP4 maintains the original frequency control (S13).

When the DSP4 determines that the third DRC process is not on (S12: No), the DSP4 determines whether or not the fourth DRC process is on (S14). When the DSP4 determines that the fourth DRC process is on (S14: Yes), the DSP4 extends the high cutoff frequency of the second BPF process to a high frequency range (S15). On the other hand, when it is determined that the fourth DRC process is not turned on (S14: No), the DSP4 maintains the original frequency control (S13).

When the DSP4 determines that the second DRC process is not on (S11: No), it determines whether or not the third DRC process is on (S16). When the DSP4 determines that the third DRC process is not on (S16: No), the DSP4 determines whether or not the fourth DRC process is on (S14). When the DSP4 determines that the third DRC process is on (S16: Yes), it determines whether or not the fourth DRC process is on (S17). When the DSP4 determines that the fourth DRC processing is on (S17: Yes), the DSP4 shifts the high cutoff frequency of the first BPF processing and the low cutoff frequency of the second BPF processing to a high frequency (S18).

When the DSP4 determines that the fourth DRC process is not on (S4: No), it determines whether or not the first DRC process is on (S19). When it is determined that the first DRC process is not on (S19: No), the DSP4 shifts the high cutoff frequency of the second BPF process to a high frequency range (S20). On the other hand, when it is determined that the first DRC processing is on (S19: Yes), the DSP4 raises the low cutoff frequency of the low frequency EQ processing and extends the high cutoff frequency of the first BPF processing to the high frequency (S21). .. The DSP4 performs the processing of S11 after the processing of S13, S15, S18, S20, or S21.

As described above, in the present embodiment, when the audio signal subjected to the second BPF processing is compressed in the third DRC processing, the high cutoff frequency of the first BPF processing is the high cutoff frequency of the second BPF processing. Is changed to the same value as. As a result, the component of the squawker band is also output from the woofer, so that the sound pressure in the squawker band can be increased. Therefore, in order to prevent the breaking sound, it is possible to obtain a volume that does not lose the musicality even when the level of the audio signal is limited.

Further, in the present embodiment, when the audio signal subjected to the LPF processing is compressed in the first DRC processing and the audio signal subjected to the second BPF processing is compressed in the third DRC processing, the first BPF processing is performed. The high cutoff frequency of is changed to the same value as the high cutoff frequency of the second BPF processing, and the low cutoff frequency of the low frequency EQ processing is raised. As a result, since the component of the squawker band is also output from the woofer, the sound pressure in the squawker band can be increased, and the disruption of the woofer output is prevented.

Further, in the present embodiment, in the fourth DRC processing, when the audio signal subjected to the HPF processing is compressed, the high cutoff frequency of the second BPF processing is extended to a high region. As a result, the tweeter band component is output from the squawker, so that the sound pressure in the tweeter band can be increased.

Further, in the present embodiment, when the audio signal subjected to the second BPF processing is compressed in the third DRC processing and the audio signal subjected to the HPF processing is compressed in the fourth DRC processing, the first BPF processing is performed. The high cutoff frequency and the low cutoff frequency of the second BPF processing are shifted to the high frequency, and the high cutoff frequency of the second BPF processing is shifted to the high frequency. As a result, the component of the squawker band is supplemented by the woofer, and the squawker is prevented from collapsing. Further, since the component of the tweeter band is output from the squawker, the sound pressure in the tweeter band can be enhanced.

(Third Embodiment)
The signal processing by DSP4 in the third embodiment is the same as the signal processing by DSP4 in the first embodiment shown in FIG. In the present embodiment, the high cutoff frequency of the BPF processing and the low cutoff frequency of the low EQ processing are changed based on the volume value in the first volume processing.

When the volume value of the first volume processing is equal to or higher than a predetermined value, the DSP4 extends the high cutoff frequency of the BPF processing to a high frequency as shown in FIG. 3 (1), and as shown in FIG. 3 (2). In addition, the low cutoff frequency of the low frequency EQ processing is raised. The DSP4 maintains the original frequency control when the volume value of the first volume processing is not equal to or more than a predetermined value. That is, DSP4 does not change the high cutoff frequency of the BPF processing and the low cutoff frequency of the low EQ processing.

As described above, in the present embodiment, when the volume value in the first volume processing is equal to or higher than a predetermined value, the high cutoff frequency of the BPF processing is extended to the high frequency range. As a result, the high frequency component is also output from the woofer, so that the maximum volume can be obtained.

(Fourth Embodiment)
The signal processing by DSP4 in the fourth embodiment is the same as the signal processing by DSP4 in the second embodiment shown in FIG. In the present embodiment, the high cutoff frequency of the first BPF processing and the second BPF processing, and the low cutoff frequency of the low EQ processing are changed based on the volume value in the first volume processing.

When the volume value of the first volume processing is equal to or higher than a predetermined value, the DSP4 sets the high cutoff frequency of the first BPF processing to the high cutoff frequency of the second BPF processing as shown in FIGS. 6 (a) and 6 (1). Change to the same value as. When the volume value of the first volume processing is equal to or higher than a predetermined value, the DSP 4 raises the low cutoff frequency of the low frequency EQ processing as shown in FIGS. 6 (a) and 6 (2). When the volume value of the first volume processing is equal to or higher than a predetermined value, the DSP4 extends the high cutoff frequency of the second BPF processing to a high frequency as shown in FIGS. 6 (b) and 6 (3).

The DSP4 does not change the high cutoff frequency of the first BPF processing, the second BPF processing, and the low cutoff frequency of the low EQ processing when the volume value of the first volume processing is not equal to or more than a predetermined value.

As described above, in the present embodiment, when the volume value in the first volume processing is equal to or higher than a predetermined value, the high cutoff frequency of the first BPF processing becomes the same value as the high cutoff frequency of the second BPF processing. Be changed. As a result, the component of the squawker band is also output from the woofer, so that the maximum volume can be obtained.

(Fifth Embodiment)
The signal processing by DSP4 in the fifth embodiment is the same as the signal processing by DSP4 in the first embodiment shown in FIG. In the present embodiment, the high cutoff frequency of the BPF processing and the low cutoff frequency of the low EQ processing are changed based on the volume value in the first volume processing. In addition to this, in the present embodiment, in the DRC processing, the cutoff frequency of the LPF processing, the BPF processing, the HPF processing, and the low frequency cutoff frequency of the low frequency EQ processing are changed based on whether or not the audio signal is compressed. To do.

When the volume value of the first volume processing is equal to or higher than a predetermined value, the DSP4 extends the high cutoff frequency of the BPF processing to a high frequency as shown in FIG. 3 (1), and as shown in FIG. 3 (2). In addition, the low cutoff frequency of the low frequency EQ processing is raised. The DSP4 maintains the original frequency control when the volume value of the first volume processing is not equal to or more than a predetermined value. That is, DSP4 does not change the high cutoff frequency of the BPF processing and the low cutoff frequency of the low EQ processing.

Further, when the DSP4 compresses the audio signal subjected to the HPF processing in the third DRC processing and does not compress the audio signal subjected to the LPF processing in the first DRC processing, as shown in FIG. 3 (1). In addition, the high cutoff frequency of BPF processing is extended to high frequencies. For example, DSP4 changes the high cutoff frequency of BPF processing to the frequency indicated by the broken line. Further, when the DSP4 compresses the audio signal subjected to the HPF processing in the third DRC processing and compresses the audio signal subjected to the LPF processing in the first DRC processing, as shown in FIG. 3 (1). In addition, the high cutoff frequency of the BPF processing is extended to the high frequency, and the low cutoff frequency of the low frequency EQ processing is raised as shown in (2) of FIG.

The DSP4 maintains the original frequency control when compressing the BPF-processed audio signal in the second DRC process. That is, DSP4 does not change the cutoff frequency of LPF processing, BPF processing, HPF processing, and the low cutoff frequency of low frequency EQ processing.

(Sixth Embodiment)
The signal processing by DSP4 in the sixth embodiment is the same as the signal processing by DSP4 in the second embodiment shown in FIG. In the present embodiment, the high cutoff frequency of the first BPF processing and the second BPF processing, and the low cutoff frequency of the low EQ processing are changed based on the volume value in the first volume processing. In addition to this, in the present embodiment, in the DRC processing, the cutoff frequency of the LPF processing, the first BPF processing, the second BPF processing, the HPF processing, and the low frequency EQ processing are low, based on whether or not the audio signal is compressed. Change the cutoff frequency.

When the volume value of the first volume processing is equal to or higher than a predetermined value, the DSP4 sets the high cutoff frequency of the first BPF processing to the high cutoff frequency of the second BPF processing as shown in FIGS. 6 (a) and 6 (1). Change to the same value as. When the volume value of the first volume processing is equal to or higher than a predetermined value, the DSP 4 raises the low cutoff frequency of the low frequency EQ processing as shown in FIGS. 6 (a) and 6 (2). When the volume value of the first volume processing is equal to or higher than a predetermined value, the DSP4 extends the high cutoff frequency of the second BPF processing to a high frequency as shown in FIGS. 6 (b) and 6 (3).

The DSP4 does not change the high cutoff frequency of the first BPF processing, the second BPF processing, and the low cutoff frequency of the low EQ processing when the volume value of the first volume processing is not equal to or more than a predetermined value.

Further, when the DSP4 compresses the audio signal subjected to the second BPF processing in the third DRC processing and does not compress the audio signal subjected to the LPF processing in the first DRC processing, FIGS. 6 (a) and 6 (1). As shown in, the high cutoff frequency of the first BPF processing is changed to the same value as the high cutoff frequency of the second BPF processing. The DSP4 is shown in FIGS. 6 (a) and 6 (1) when the audio signal subjected to the second BPF process is compressed in the third DRC process and the audio signal subjected to the LPF process is compressed in the first DRC process. As described above, the high cutoff frequency of the first BPF processing is changed to the same value as the high cutoff frequency of the second BPF processing, and as shown in FIGS. 6A and 6A, the low cutoff frequency of the low EQ processing is changed. Raise.

The DSP4 is shown in FIGS. 6 (b) and 6 (3) when the audio signal subjected to the HPF processing is compressed in the 4th DRC processing and the audio signal subjected to the 2nd BPF processing is not compressed in the 3rd DRC processing. As described above, the high cutoff frequency of the second BPF processing is extended to the high frequency range. The DSP4 compresses the audio signal subjected to the HPF processing in the 4th DRC processing, compresses the audio signal subjected to the 2nd BPF processing in the 3rd DRC processing, and performs the 1st BPF processing in the 2nd DRC processing. When the audio signal is not compressed, as shown in FIGS. 6 (b) and 6 (4), the high cutoff frequency of the first BPF processing and the low cutoff frequency of the second BPF processing are shifted to high frequencies, and FIG. b) As shown in (3), the high cutoff frequency of the second BPF processing is shifted to the high frequency.

The DSP4 maintains the original frequency control in the first BPF processing and the low frequency EQ processing when the audio signal subjected to the first BPF processing is compressed in the second DRC processing. That is, DSP4 does not change the cutoff frequency of the first BPF processing and the low cutoff frequency of the low-frequency EQ processing.

The DSP4 compresses the audio signal subjected to the HPF processing in the fourth DRC processing, compresses the audio signal subjected to the second BPF processing in the third DR processing, and performs the first BPF processing in the second DRC processing. Maintain original frequency control when compressing the signal. That is, DSP4 does not change the cutoff frequency of LPF processing, first BPF processing, second BPF processing, HPF processing, and low frequency cutoff frequency of low frequency EQ processing.

Although the embodiments of the present invention have been described above, the embodiments to which the present invention can be applied are not limited to the above-described embodiments, and as illustrated below, they are appropriately used without departing from the spirit of the present invention. It is possible to make changes.

(Modification example)
The DSP4 has a low-pass filter (LPF) process for extracting the low-pass component of the audio signal, a high-pass filter (HPF) process for extracting the high-pass component of the audio signal, and an interval between the low-pass component and the high-frequency component of the audio signal. Bandpass filter (BPF) processing that extracts the predetermined frequency band component of the above, and the first compression that compresses the lowpass filtered audio signal when the lowpass filtered audio signal is above the predetermined signal level. (DRC) processing, second compression (DRC) processing for compressing the bandpass filtered audio signal when the bandpass filtered audio signal is above a predetermined signal level, and high-pass filter processing. When the performed audio signal is equal to or higher than a predetermined signal level, a third compression (DRC) process for compressing the high-pass filtered audio signal is performed. The DSP4 changes the cutoff frequency of the low-pass filter process, the band-pass filter process, and the high-pass filter process when the audio signal is compressed in any of the first compression process, the second compression process, and the third compression process.

In the modified example, when the audio signal is compressed in any of the first compression process, the second compression process, and the third compression process, the cutoff frequencies of the low-pass filter process, the band-pass filter process, and the high-pass filter process are changed. To. As a result, the audio signal components output to the speaker unit have overlapping bands, so that the number of units to be reproduced increases and the maximum volume can be increased.

The present invention can be suitably adopted for a signal processing device for processing an audio signal, a signal processing method, and a speaker device including the signal processing device.

1 Speaker device 2 Microcomputer 3 Operation unit 4 DSP (signal processing device)
5 DAC
6 Amplifier 7 Speaker 8 Wireless module

Claims (38)

Low-pass filter processing that extracts low-frequency components of audio signals,
High-pass filter processing that extracts high-frequency components of audio signals,
Bandpass filter processing that extracts a predetermined frequency band component between the low frequency component and the high frequency component of the audio signal,
The first compression process for compressing the low-pass filtered audio signal when the low-pass filtered audio signal is equal to or higher than a predetermined signal level.
A second compression process for compressing the bandpass filtered audio signal when the bandpass filtered audio signal is above a predetermined signal level.
A third compression process that compresses the high-pass filtered audio signal when the high-pass filtered audio signal is above a predetermined signal level.
Performs a synthesis process for synthesizing the low frequency component of the audio signal and the predetermined frequency band component of the audio signal.
A signal processing device characterized in that, in the third compression process, when the audio signal subjected to the high-pass filter process is compressed, the high-frequency cutoff frequency of the band-pass filter process is extended to a high frequency range. A low-frequency equalizing process for boosting the low-frequency component of the low-pass filtered audio signal is further performed.
When the audio signal subjected to the low-pass filter is compressed in the first compression process and the audio signal subjected to the high-pass filter process is compressed in the third compression process, the height of the bandpass filter process is high. The signal processing apparatus according to claim 1, wherein the region cutoff frequency is extended to a high region and the low region cutoff frequency of the low frequency equalizing process is increased. In the second compression process, when the audio signal subjected to the bandpass filter process is compressed, the low pass filter process, the bandpass filter process, the cutoff frequency in the high pass filter process, and the low frequency equalizing process are performed. The signal processing device according to claim 2, wherein the low-pass cutoff frequency is not changed. When the audio signal subjected to the bandpass filter processing is not compressed in the second compression processing and the audio signal subjected to the highpass filter processing is not compressed in the third compression processing, the lowpass filter processing is performed. The signal processing apparatus according to claim 1 or 2, wherein the cutoff frequency in the bandpass filter processing and the highpass filter processing is not changed. The audio signal subjected to the synthesis processing is output to the woofer and is output.
The signal processing device according to any one of claims 1 to 4, wherein the audio signal subjected to the third compression process is output to a tweeter. Low-pass filter processing that extracts low-frequency components of audio signals,
High-pass filter processing that extracts high-frequency components of audio signals,
A first bandpass filter process that extracts a first predetermined frequency band component between a low frequency component and a high frequency component of an audio signal, and
A second bandpass filter process that extracts a second predetermined frequency band component between the low frequency component and the high frequency component of the audio signal, and
The first compression process for compressing the low-pass filtered audio signal when the low-pass filtered audio signal is equal to or higher than a predetermined signal level.
A second compression process for compressing the audio signal subjected to the first bandpass filter process when the audio signal subjected to the first bandpass filter process is equal to or higher than a predetermined signal level.
A third compression process for compressing the audio signal subjected to the second bandpass filter process when the audio signal subjected to the second bandpass filter process is equal to or higher than a predetermined signal level.
A fourth compression process that compresses the high-pass filtered audio signal when the high-pass filtered audio signal is above a predetermined signal level.
A synthesis process for synthesizing the low frequency component of the audio signal and the first predetermined frequency band component of the audio signal is performed.
In the third compression process, when the audio signal subjected to the second bandpass filter process is compressed, the high cutoff frequency of the first bandpass filter process is set to the high cutoff frequency of the second bandpass filter process. A signal processing device characterized by changing to the same value as the frequency. A low-frequency equalizing process for boosting the low-frequency component of the low-pass filtered audio signal is further performed.
When the audio signal subjected to the low-pass filter is compressed in the first compression process and the audio signal subjected to the second high-pass filter process is compressed in the third compression process, the first bandpass is performed. 6. Claim 6 characterized in that the high cutoff frequency of the filtering process is changed to the same value as the high cutoff frequency of the second bandpass filter processing, and the low cutoff frequency of the low frequency equalizing process is increased. The signal processing apparatus according to. The sixth or seven claim is characterized in that, in the fourth compression process, when the audio signal subjected to the high-pass filter process is compressed, the high cutoff frequency of the second band-pass filter process is extended to a high frequency range. The signal processing device described. When the audio signal subjected to the second bandpass filter processing is compressed in the third compression process and the audio signal subjected to the highpass filter process is compressed in the fourth compression process, the first Shifting the high cutoff frequency of the bandpass filter processing and the low cutoff frequency of the second bandpass filter processing to a high range, and shifting the high cutoff frequency of the second bandpass filter processing to a high range. The signal processing apparatus according to any one of claims 6 to 8. In the second compression process, when the audio signal subjected to the first bandpass filter process is compressed, the cutoff frequency of the first bandpass filter process and the low cutoff frequency of the low frequency equalizing process are not changed. The signal processing apparatus according to claim 7. In the second compression process, the audio signal subjected to the first bandpass filter process is compressed.
In the third compression process, the audio signal subjected to the second bandpass filter process is compressed and
In the fourth compression process, when the audio signal subjected to the high-pass filter process is compressed,
The invention according to any one of claims 6 to 10, wherein the cutoff frequency in the low-pass filter process, the first band-pass filter process, the second band-pass filter process, and the high-pass filter process is not changed. Signal processing device. The audio signal subjected to the synthesis processing is output to the woofer and is output.
The audio signal subjected to the third compression process is output to the squawker and is output.
The signal processing device according to any one of claims 6 to 11, wherein the audio signal subjected to the fourth compression process is output to a tweeter. The first volume processing that attenuates the audio signal based on the received volume value,
Low-pass filter processing that extracts low-frequency components of audio signals,
High-pass filter processing that extracts high-frequency components of audio signals,
Bandpass filter processing that extracts a predetermined frequency band component between the low frequency component and the high frequency component of the audio signal,
Performs a synthesis process for synthesizing the low frequency component of the audio signal and the predetermined frequency band component of the audio signal.
A signal processing device characterized in that the high cutoff frequency of the bandpass filter processing is extended to a high frequency range when the volume value in the first volume processing is equal to or higher than a predetermined value. A low-frequency equalizing process for boosting the low-frequency component of the low-pass filtered audio signal is further performed.
The signal processing apparatus according to claim 13, wherein when the volume value in the first volume processing is equal to or higher than a predetermined value, the low-frequency cutoff frequency of the low-frequency equalizing process is increased. The claim is characterized in that the high cutoff frequency of the bandpass filter processing and the low cutoff frequency of the low frequency equalizing processing are not changed when the volume value in the first volume processing is not equal to or more than a predetermined value. 14. The signal processing apparatus according to 14. The first compression process for compressing the low-pass filtered audio signal when the low-pass filtered audio signal is equal to or higher than a predetermined signal level.
A second compression process for compressing the bandpass filtered audio signal when the bandpass filtered audio signal is above a predetermined signal level.
When the audio signal subjected to the high-pass filter processing is above a predetermined signal level,
The third compression process of compressing the audio signal subjected to the high-pass filter process is further performed.
Any of claims 13 to 15, characterized in that, in the third compression process, when the audio signal subjected to the high-pass filter process is compressed, the high-frequency cutoff frequency of the band-pass filter process is extended to a high frequency range. The signal processing apparatus according to item 1. A low-frequency equalizing process for boosting the low-frequency component of the low-pass filtered audio signal is further performed.
When the audio signal subjected to the low-pass filter is compressed in the first compression process and the audio signal subjected to the high-pass filter process is compressed in the third compression process, the height of the bandpass filter process is high. The signal processing apparatus according to claim 16, wherein the region cutoff frequency is extended to a high region and the low region cutoff frequency of the low frequency equalizing process is increased. In the second compression process, when the audio signal subjected to the bandpass filter process is compressed, the low pass filter process, the bandpass filter process, the cutoff frequency in the high pass filter process, and the low frequency equalizing process are performed. The signal processing device according to claim 17, wherein the low-pass cutoff frequency is not changed. When the audio signal subjected to the bandpass filter processing is not compressed in the second compression processing and the audio signal subjected to the highpass filter processing is not compressed in the third compression processing, the lowpass filter processing is performed. The signal processing apparatus according to claim 16 or 17, wherein the cutoff frequency in the bandpass filter processing and the highpass filter processing is not changed. The audio signal subjected to the synthesis processing is output to the woofer and is output.
The signal processing device according to any one of claims 13 to 19, wherein the audio signal subjected to the third compression process is output to a tweeter. The first volume processing that attenuates the audio signal based on the received volume value,
Low-pass filter processing that extracts low-frequency components of audio signals,
High-pass filter processing that extracts high-frequency components of audio signals,
A first bandpass filter process that extracts a first predetermined frequency band component between a low frequency component and a high frequency component of an audio signal, and
A second bandpass filter process that extracts a second predetermined frequency band component between the low frequency component and the high frequency component of the audio signal, and
A synthesis process for synthesizing the low frequency component of the audio signal and the first predetermined frequency band component of the audio signal is performed.
When the volume value in the first volume processing is equal to or higher than a predetermined value, the high cutoff frequency of the first bandpass filter processing is changed to the same value as the high cutoff frequency of the second bandpass filter processing. A signal processing device characterized by. The signal processing apparatus according to claim 21, wherein the high cutoff frequency of the second bandpass filter processing is extended to a high frequency range when the volume value in the first volume processing is equal to or higher than a predetermined value.
A low-frequency equalizing process for boosting the low-frequency component of the low-pass filtered audio signal is further performed.
The signal processing apparatus according to claim 21 or 22, wherein when the volume value in the first volume processing is equal to or higher than a predetermined value, the low-frequency cutoff frequency of the low-frequency equalizing process is increased. When the volume value in the first volume value is not equal to or more than a predetermined value, the high cutoff frequency of the first bandpass filter processing, the second bandpass filter, and the low cutoff frequency of the low frequency equalizing processing are not changed. The signal processing apparatus according to claim 23. The first compression process for compressing the low-pass filtered audio signal when the low-pass filtered audio signal is equal to or higher than a predetermined signal level.
A second compression process for compressing the audio signal subjected to the first bandpass filter process when the audio signal subjected to the first bandpass filter process is equal to or higher than a predetermined signal level.
A third compression process for compressing the audio signal subjected to the second bandpass filter process when the audio signal subjected to the second bandpass filter process is equal to or higher than a predetermined signal level.
When the audio signal subjected to the high-pass filter processing is equal to or higher than a predetermined signal level, a fourth compression process for compressing the audio signal subjected to the high-pass filter processing is further performed.
In the third compression process, when the audio signal subjected to the second bandpass filter process is compressed, the high cutoff frequency of the first bandpass filter process is set to the high cutoff frequency of the second bandpass filter process. The signal processing apparatus according to any one of claims 21 to 24, wherein the value is changed to the same value as the frequency. A low-frequency equalizing process for boosting the low-frequency component of the low-pass filtered audio signal is further performed.
When the audio signal subjected to the low-pass filter is compressed in the first compression process and the audio signal subjected to the second high-pass filter process is compressed in the third compression process, the first bandpass is performed. 25. Claim 25, wherein the high cutoff frequency of the filtering process is changed to the same value as the high cutoff frequency of the second bandpass filter processing, and the low cutoff frequency of the low frequency equalizing process is raised. The signal processing apparatus according to. 25 or 26 according to claim 25 or 26, wherein in the fourth compression process, when the audio signal subjected to the high-pass filter process is compressed, the high cutoff frequency of the second band-pass filter process is extended to a high frequency range. The signal processing device described. When the audio signal subjected to the second bandpass filter processing is compressed in the third compression process and the audio signal subjected to the highpass filter process is compressed in the fourth compression process, the first Shifting the high cutoff frequency of the bandpass filter processing and the low cutoff frequency of the second bandpass filter processing to a high range, and shifting the high cutoff frequency of the second bandpass filter processing to a high range. The signal processing apparatus according to any one of claims 25 to 27. In the second compression process, when the audio signal subjected to the first bandpass filter process is compressed, the cutoff frequency of the first bandpass filter process and the low cutoff frequency of the low frequency equalizing process are not changed. 26. The signal processing apparatus according to claim 26. In the second compression process, the audio signal subjected to the first bandpass filter process is compressed.
In the third compression process, the audio signal subjected to the second bandpass filter process is compressed and
In the fourth compression process, when the audio signal subjected to the high-pass filter process is compressed,
The invention according to any one of claims 25 to 29, wherein the cutoff frequency in the low-pass filter process, the first band-pass filter process, the second band-pass filter process, and the high-pass filter process is not changed. Signal processing device. The audio signal subjected to the synthesis processing is output to the woofer and is output.
The audio signal subjected to the third compression process is output to the squawker and is output.
The signal processing device according to any one of claims 21 to 30, wherein the audio signal subjected to the fourth compression process is output to a tweeter. The signal processing device according to any one of claims 1 to 31 and
A speaker to which an audio signal from the signal processing device is input and
A speaker device characterized by being equipped with. Low-pass filter processing that extracts low-frequency components of audio signals,
High-pass filter processing that extracts high-frequency components of audio signals,
Bandpass filter processing that extracts a predetermined frequency band component between the low frequency component and the high frequency component of the audio signal,
The first compression process for compressing the low-pass filtered audio signal when the low-pass filtered audio signal is equal to or higher than a predetermined signal level.
A second compression process for compressing the bandpass filtered audio signal when the bandpass filtered audio signal is above a predetermined signal level.
When the audio signal subjected to the high-pass filter processing is above a predetermined signal level,
The third compression process of compressing the audio signal subjected to the high-pass filter process is performed.
When the audio signal is compressed in any of the first compression process, the second compression process, and the third compression process, the cutoff frequencies of the low-pass filter process, the band-pass filter process, and the high-pass filter process are changed. A signal processing method characterized by Low-pass filter processing that extracts low-frequency components of audio signals,
High-pass filter processing that extracts high-frequency components of audio signals,
Bandpass filter processing that extracts a predetermined frequency band component between the low frequency component and the high frequency component of the audio signal,
The first compression process for compressing the low-pass filtered audio signal when the low-pass filtered audio signal is equal to or higher than a predetermined signal level.
A second compression process for compressing the bandpass filtered audio signal when the bandpass filtered audio signal is above a predetermined signal level.
A third compression process that compresses the high-pass filtered audio signal when the high-pass filtered audio signal is above a predetermined signal level.
Performs a synthesis process for synthesizing the low frequency component of the audio signal and the predetermined frequency band component of the audio signal.
A signal processing method characterized in that, in the third compression process, when the audio signal subjected to the high-pass filter process is compressed, the high-frequency cutoff frequency of the band-pass filter process is extended to a high frequency range. Low-pass filter processing that extracts low-frequency components of audio signals,
High-pass filter processing that extracts high-frequency components of audio signals,
A first bandpass filter process that extracts a first predetermined frequency band component between a low frequency component and a high frequency component of an audio signal, and
A second bandpass filter process that extracts a second predetermined frequency band component between the low frequency component and the high frequency component of the audio signal, and
The first compression process for compressing the low-pass filtered audio signal when the low-pass filtered audio signal is equal to or higher than a predetermined signal level.
A second compression process for compressing the audio signal subjected to the first bandpass filter process when the audio signal subjected to the first bandpass filter process is equal to or higher than a predetermined signal level.
A third compression process for compressing the audio signal subjected to the second bandpass filter process when the audio signal subjected to the second bandpass filter process is equal to or higher than a predetermined signal level.
A fourth compression process that compresses the high-pass filtered audio signal when the high-pass filtered audio signal is above a predetermined signal level.
A synthesis process for synthesizing the low frequency component of the audio signal and the first predetermined frequency band component of the audio signal is performed.
In the third compression process, when the audio signal subjected to the second bandpass filter process is compressed, the high cutoff frequency of the first bandpass filter process is set to the high cutoff frequency of the second bandpass filter process. A signal processing method characterized by changing to the same value as the frequency. The first volume processing that attenuates the audio signal based on the received volume value,
Low-pass filter processing that extracts low-frequency components of audio signals,
High-pass filter processing that extracts high-frequency components of audio signals,
Bandpass filter processing that extracts a predetermined frequency band component between the low frequency component and the high frequency component of the audio signal,
Performs a synthesis process for synthesizing the low frequency component of the audio signal and the predetermined frequency band component of the audio signal.
A signal processing method comprising extending the high cutoff frequency of the bandpass filter processing to a high frequency range when the volume value in the first volume processing is equal to or higher than a predetermined value. The first volume processing that attenuates the audio signal based on the received volume value,
Low-pass filter processing that extracts low-frequency components of audio signals,
High-pass filter processing that extracts high-frequency components of audio signals,
A first bandpass filter process that extracts a first predetermined frequency band component between a low frequency component and a high frequency component of an audio signal, and
A second bandpass filter process that extracts a second predetermined frequency band component between the low frequency component and the high frequency component of the audio signal, and
A synthesis process for synthesizing the low frequency component of the audio signal and the first predetermined frequency band component of the audio signal is performed.
When the volume value in the first volume processing is equal to or higher than a predetermined value, the high cutoff frequency of the first bandpass filter processing is changed to the same value as the high cutoff frequency of the second bandpass filter processing. A signal processing method characterized by. Low-pass filter processing that extracts low-frequency components of audio signals,
High-pass filter processing that extracts high-frequency components of audio signals,
Bandpass filter processing that extracts a predetermined frequency band component between the low frequency component and the high frequency component of the audio signal,
The first compression process for compressing the low-pass filtered audio signal when the low-pass filtered audio signal is equal to or higher than a predetermined signal level.
A second compression process for compressing the bandpass filtered audio signal when the bandpass filtered audio signal is above a predetermined signal level.
When the audio signal subjected to the high-pass filter processing is above a predetermined signal level,
The third compression process of compressing the audio signal subjected to the high-pass filter process is performed.
When the audio signal is compressed in any of the first compression process, the second compression process, and the third compression process, the cutoff frequencies of the low-pass filter process, the band-pass filter process, and the high-pass filter process are changed. A signal processing method characterized by

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