Patent Description:
An AV (Audio Visual) amplifier may reproduce sound using all speakers connected to the amplifier. In addition, a HiFi (Hi Fidelity) amplifier may be able to use a speaker by switching speakers according to a sound source (classic or rock, for example) to be reproduced. Then, various methods have been proposed as technology to measure speaker characteristics and optimize the speaker characteristics using a measurement result (see Patent Literature <NUM>, for example).

Patent Literature <NUM>: Unexamined <CIT>. Document <CIT> discloses a sound reproduction device with a control unit that applies filters to an output signal based on a selected source input for receiving a source signal. Document <CIT> discloses a system where equalizer settings are loaded based on a user selection for a speaker output configuration. Document <CIT> discloses an amplifier configured to concurrently drive two bi-wired speakers or four single speakers with four amplifiers.

However, even when the optimization technology in Patent Literature <NUM> or the like is merely applied to an amplifier capable of switching speakers, a user will need to, for example, call a measurement result or to remeasure speaker characteristics after the speaker is switched, thereby forcing complicate operations on the user.

Accordingly, an object of one preferred embodiment of the present invention is to provide a signal processing device capable of optimizing characteristics of a speaker automatically, which is selected by switching, according to the switching of the speaker.

A signal processing device according to a preferred embodiment of the present invention is defined in claim <NUM>.

According to one preferred embodiment of the present invention, the characteristics of the speaker selected by the switching can be optimized automatically, according to the switching of the speaker.

<FIG> is a block diagram conceptually showing a configuration of a signal processing device <NUM> in accordance with a first preferred embodiment. Further, <FIG> is a conceptual diagram showing an application example of the signal processing device <NUM>. As shown in <FIG>, the signal processing device <NUM> includes an input portion <NUM>, an obtaining portion <NUM>, an output portion <NUM>, a switching execution portion <NUM>, a storage portion <NUM>, a signal processing portion <NUM>, an operation reception portion <NUM>, and a control portion <NUM> that controls these components collectively.

The input portion <NUM> is an interface used for inputting an audio signal to the signal processing device <NUM>. Herein, the audio signal to be inputted to the signal processing device <NUM> is an audio signal that is inputted from reading devices (not shown) such as a CD player, a DVD player, and an LD player. Hereinafter, the audio signal is referred to as "input audio signal Sin.

Specifically, the input portion <NUM> has an interface that receives input of a digital audio signal, such as a HDMI (registered trademark) (High-Definition Multimedia Interface) or an S/PDIF (Sony Philips Digital Interface). A CD player or the like is connected to the interface. The input portion <NUM> further has an interface that receives input of an analog audio signal. An LD player or the like is connected to the interface. Note that, the input portion <NUM> may contain an ADC (Analog to Digital Converter) that converts the inputted analog audio signal into a digital signal.

The obtaining portion <NUM> is an interface that receives input of a sound signal to the signal processing device <NUM>. A microphone <NUM> (see <FIG>) is connected to the obtaining portion <NUM>. A sound, which is inputted to the microphone <NUM>, is converted into a sound signal in the microphone <NUM>, and inputted to the obtaining portion <NUM>. Note that, the sound signal may be an analog signal or may be a digital signal. In the case where the sound signal is an analog signal, the obtaining portion <NUM> may contain an ADC that converts the sound signal into a digital signal.

The output portion <NUM> is an interface used for outputting the audio signal to a speaker. Herein, the audio signal, which is outputted to the speaker, is an audio signal that is subjected to signal processing in the signal processing portion <NUM>, as described later. Hereinafter, this audio signal is referred to as "output audio signal Sout.

In the present preferred embodiment, the output portion <NUM> includes an A-channel and a B-channel as an output channel to which the speaker is connected. As an example, a pair of speakers <NUM> and 21R are connected to the A-channel, and a pair of speakers <NUM> and 22R are connected to the B-channel.

The switching execution portion <NUM> is a switch circuit, for example. The switching execution portion <NUM> switches to select one or both of the A-channel and the B-channel to be connected to the signal processing portion <NUM>, according to a switching execution instruction from the control portion <NUM>. Specifically, in the switching execution portion <NUM>, it is possible to execute switching to select only the A-channel, switching to select only the B-channel, and switching to select both the A-channel and the B-channel.

The operation reception portion <NUM> is a user interface for receiving an operation instruction from a user. In the present preferred embodiment, the operation reception portion <NUM> includes a switching reception portion <NUM> that receives input of a switching instruction for switching the speaker from a user. The switching reception portion <NUM> is, for example, a changeover switch of a multi-stage type or a switching dial. Note that, the operation reception portion <NUM> may include a display portion for presenting various information to a user. Further, the operation reception portion <NUM> may include a reception portion that receives an operation signal from mobile terminals, such as a remote controller and a smart phone. The operation reception portion <NUM> may receive the operation signal, which is received by the reception portion, as an operation instruction.

When only the A-channel is selected, only a pair of speakers <NUM> and 21R, which are connected to the A-channel, are used as a supply destination of the output audio signal Sout. When only the B-channel is selected, only a pair of speakers <NUM> and 22R, which are connected to the B-channel, are used as a supply destination of the output audio signal Sout. When both the A-channel and the B-channel are selected, all of the speakers <NUM>, 21R, <NUM>, and 22R, which are connected to these channels, are used as a supply destination of the output audio signal Sout.

In other words, the speaker serving as a supply destination of the output audio signal Sout is switched by the switching execution portion <NUM>, according to the switching instruction received by the switching reception portion <NUM>. Such switching of the speaker includes a concept of an increase or decrease in the number of speakers.

Note that, the switching execution portion <NUM> is not limited to a switch circuit, but may be an execution portion of the control portion <NUM>, which internally executes the switching (switch an output channel) of a speaker according to the switching instruction from a user. Such an execution portion can also be applied to the case where the output audio signal Sout is supplied to the speaker wirelessly from the signal processing device <NUM>.

The storage portion <NUM> stores, as data, a default setting Id for achieving default signal processing. For instance, the default setting Id includes a setting for equalizing a left and right balance of the speaker, a setting for flattening frequency characteristics (F characteristics), and the like. As an example, the default setting Id includes various kinds of settings (setting of successive model specifications) that have been used without being greatly changed from successive models of amplifiers or the like.

The storage portion <NUM> further stores the optimal setting Ia as data, in association with the switching (only the A-channel, only the B-channel, the A-channel + the B-channel) of the speaker. Herein, the optimal setting Ia corresponds to a measurement result obtained by measuring characteristics (speaker characteristics) of the speaker selected by the switching of the speaker. Specifically, the optimal setting Ia includes various kinds of settings (a setting of frequency characteristics (F characteristics), a setting of output timing (delay), a setting of a volume level, and the like) for optimizing the characteristics of the speaker according to the switching of the speaker. Note that, the signal processing device <NUM> performs the following processing to obtain the optimal setting Ia.

<FIG> is a flowchart showing processing for obtaining the optimal setting Ia. When the signal processing device <NUM> detects that the microphone <NUM> has been connected to the obtaining portion <NUM>, or when an instruction of starting the measurement is received from a user, the processing is started. At this time, the microphone <NUM> is installed at a listening position Pa by a user (see <FIG>). After the control processing is started, the signal processing device <NUM> measures a test sound at the listening position Pa by using the microphone <NUM>, while emitting the test sound from the speaker selected by the switching of the speaker (Step S11). Next, the signal processing device <NUM> analyzes the signal, which is obtained through the measurement, to derive various kinds of settings for optimizing the speaker characteristics (Step S12). Subsequently, by the signal processing device <NUM>, the various kinds of settings, which are derived at Step S12, are stored in the storage portion <NUM> as the optimal setting Ia (Step S13). After that, when the signal processing device <NUM> detects that the microphone <NUM> has been removed from the obtaining portion <NUM> (Step S14), the processing for obtaining the optimal setting Ia is completed. Note that, the processing may be completed when this processing is performed for all switching operations and the optimal setting Ia corresponding to each switching is completely acquired.

The signal processing portion <NUM> is a DSP (Digital Signal Processor) for example, and selectively reads out data related to any one of the default setting Id and the optimal setting Ia from the storage portion <NUM> according to a read-out execution instruction from the control portion <NUM>. Then, the signal processing portion <NUM> performs signal processing of the input audio signal Sin, using the read-out data.

If the default setting Id is used to process the input audio signal Sin, an output audio signal Sout on which the various kinds of settings in the default setting Id are reflected is obtained. This output audio signal Sout is supplied to the speaker, so that a default sound is outputted. Further, if the optimal setting Ia is used to process the input audio signal Sin, an output audio signal Sout on which the various kinds of settings in the optimal setting Ia are reflected is obtained. This output audio signal Sout is supplied to the speaker, so that an optimized sound is outputted.

The control portion <NUM>, which controls the signal processing device <NUM> collectively, is constituted by processing units such as a CPU (Central Processing Unit) and a microcomputer. In the present preferred embodiment, the control portion <NUM> performs various kinds of processing, according to the operation instruction received by the operation reception portion <NUM>, or the like. Note that, the processing performed by the control portion <NUM> is achieved by executing a program corresponding thereto through the control portion <NUM>. Such a program may be stored in a readable storage medium (e.g., a flash memory or the like), or may be stored in the storage portion <NUM>.

<FIG> is a flowchart showing reproduction processing performed in the signal processing device <NUM>. The reproduction processing is started when electric power is supplied to the signal processing device <NUM> (at the time of power on), when the microphone <NUM> is disconnected to the obtaining portion <NUM>, when the switching of the speaker is performed, and the like. Note that, if electric power is supplied to the signal processing device <NUM> in the state where the microphone <NUM> is connected to the obtaining portion <NUM>, the processing for obtaining the above-mentioned optimal setting Ia may be performed before the reproduction processing is performed.

When the reproduction processing is started, the control portion <NUM> determines whether the optimal setting Ia associated with the switching received by the switching reception portion <NUM> exists in the storage portion <NUM> or not (Step S21). When determining "exist (Yes)" at Step S21, the control portion <NUM> causes the signal processing portion <NUM> to read out the optimal setting Ia associated with the switching received by the switching reception portion <NUM>, from the storage portion <NUM> (Step S22). On the other hand, when determining "not exist (No)" at Step S21, the control portion <NUM> causes the signal processing portion <NUM> to read out the default setting Id (Step S23). In that time, the control portion <NUM> performs processing of notifying a user that the optimal setting Ia associated therewith does not exist in the storage portion <NUM> (Step S24).

Next, the signal processing portion <NUM> performs signal processing of an input audio signal Sin to be inputted (Step S25). Specifically, the signal processing portion <NUM> performs the signal processing of the input audio signal Sin, using the data (default setting Id or optimal setting Ia) which has been already read out from storage portion <NUM>. The output audio signal Sout obtained by performing the signal processing is supplied to an output channel connected via the switching execution portion <NUM>, as necessary.

According to such reproduction processing, in each switching of the speaker allowed to be received by the switching reception portion <NUM>, once the corresponding optimal setting Ia is obtained (see <FIG>), the control portion <NUM> causes the signal processing portion <NUM> to perform signal processing by using the same optimal setting Ia stored in the storage portion <NUM>, unless a change instruction (in the present preferred embodiment, connection of the microphone <NUM> to the obtaining portion <NUM>) for changing the optimal setting Ia or the like is received. Therefore, the characteristics (speaker characteristics) of the speaker selected by the switching can be optimized automatically, according to the switching of the speaker.

In this way, in the signal processing device <NUM> of the present preferred embodiment, the optimal setting Ia obtained through the measurement channel can be preserved (stored in the storage portion <NUM>) and called (read out from the storage portion <NUM>) automatically. Therefore, complicated operations for optimizing the speaker characteristics can be eliminated when the speaker is switched.

<FIG> is a block diagram showing another application example of the signal processing device <NUM>. As shown in <FIG>, each of speakers <NUM> and 21R includes a tweeter TW serving as a speaker for high pitched sounds, and a woofer WF serving as a speaker for low pitched sounds. The tweeter TW and the woofer WF may be connected to the signal processing device <NUM>, using a bi-wiring method. <FIG> shows the case where the tweeter TW is connected to the A-channel, and the woofer WF is connected to the B-channel. Switching of the speaker using such a bi-wiring method is also included in one aspect of the switching of the speaker in the present invention.

<FIG> is a block diagram conceptually showing a configuration of a signal processing device <NUM> in accordance with a second preferred embodiment. As shown in <FIG>, the switching execution portion <NUM> may include an A/B switching portion <NUM> that performs switching regarding to the A-channel and the B-channel, and an ON/OFF switching portion <NUM> that is connected to a sub-woofer SW and switches between use and non-use of the sub-woofer SW serving as a speaker for super-low pitched sounds.

The switching execution portion <NUM> can selectively switch a subject (e.g., only the A-channel, only the B-channel, the A-channel + the B-channel, the A-channel + the SW, the B-channel + the SW, or the A-channel + the B-channel + the SW) to be connected to the signal processing portion <NUM>, among the A-channel, the B-channel, and the sub-woofer SW. In this case as well, the optimal setting Ia is obtained by measuring characteristics (speaker characteristics) of the speaker selected by the switching, and the obtained optimal setting Ia is stored in the storage portion <NUM> associating with the switching of the speaker.

In this signal processing device <NUM> as well, the characteristics (speaker characteristics) of the speaker selected by the switching can be optimized automatically, according to the switching of the speaker.

The above-mentioned signal processing device <NUM> is not limited to the signal processing device that processes a two-channel audio signal, but may be a signal processing device that processes a multi-channel audio signal. In this case, speakers corresponding to the number of channels are connected to each of the A-channel and the B-channel.

<FIG> is a conceptual diagram showing the signal processing device <NUM> that processes a three-channel audio signal. <FIG> shows the case where three speakers <NUM>, 21R, and 21C are connected to one of output channels of the signal processing device <NUM>. In such a signal processing device <NUM>, switching (this switching includes processing of selecting whether or not to include a signal to be supplied to speaker 21C in the output audio signal Sout outputted from the signal processing portion <NUM>) between the case (see <FIG>) where all three speakers are used and the case (see <FIG>) where only two speakers <NUM> and 21R are used is also included in one aspect of the switching of the speaker in the present invention.

<FIG> is a block diagram conceptually showing a configuration of a signal processing device <NUM> in accordance with a fourth preferred embodiment. As shown in <FIG>, in the signal processing device <NUM>, the operation reception portion <NUM> may include a selection reception portion <NUM> that receives a selection about whether or not to perform the signal processing using the optimal setting Ia. In other words, the selection reception portion <NUM> receives, from a user, a selection instruction about whether or not to optimize speaker characteristics.

<FIG> is a flowchart showing reproduction processing performed by the signal processing device <NUM> in the fourth preferred embodiment. When the reproduction processing is started, the control portion <NUM> determines whether or not to optimize speaker characteristics according to the selection received by the selection reception portion <NUM> (Step S31).

When determining "optimized (Yes)" at Step S31, the control portion <NUM> perform the same processing (Steps S32 to S35, i.e., the processing that causes the signal processing portion <NUM> to read the optimal setting Ia) as that of Steps S21 to S24 in <FIG>. On the other hand, when determining "not optimized (No)" at Step S31, the control portion <NUM> causes the signal processing portion <NUM> to read out the default setting Id from the storage portion <NUM> (Step S36).

After that, the signal processing portion <NUM> performs signal processing of the input audio signal Sin to be inputted (Step S37).

According to the signal processing device <NUM> of the present preferred embodiment, even after the optimal setting Ia is obtained in the signal processing device <NUM>, it is possible to return to the default setting Id in which no changes have been made, and reproduce sounds. In other words, when sounds are reproduced, a user can select either an output of the optimized sound or an output of the default sound.

In the above-mentioned signal processing device <NUM>, a plurality of output channels, which are not limited to two, may be included in the output portion <NUM>. In such a signal processing device <NUM>, the switching execution portion <NUM> may switch a plurality of output channels among various combinations. Further, the signal processing device <NUM> may have a configuration that sends the output audio signal Sout to the speaker, wirelessly.

The signal processing device <NUM> may measure speaker characteristics for every speaker or for every output channel. Based on the measurement results, the signal processing device <NUM> may calculate the speaker characteristics and the optimal setting Ia, which correspond to various combinations of speakers or output channels.

Furthermore, each configuration of the above-mentioned signal processing device <NUM> is not limited to the configuration that processes an audio signal, but may be applied to a configuration that processes various kinds of sound signals, such as a signal inputted through a microphone.

<FIG> is a conceptual diagram showing another application example of the signal processing device <NUM>. As shown in <FIG>, each configuration of the above-mentioned signal processing device <NUM> is also applicable to bi-amplifiers in which two amplifiers Ap are provided. Note that, each configuration of the signal processing device <NUM> may be applied to only one of two amplifiers Ap, or may be applied to both of them. Further, with respect to the two amplifiers Ap, switching may be performed between bi-amplifiers and single amplifier. Such switching is also included in one aspect of the switching of the speaker in the present invention.

Claim 1:
A signal processing device (<NUM>) comprising:
a switching reception portion (<NUM>) that receives, from a user, an instruction for switching a supply destination of a signal to (i) a first supply destination including a first pair of speakers (<NUM>, 21R), (ii) a second supply destination including a second pair of speakers (<NUM>, 22R) different from the first pair of speakers (<NUM>, 21R), or (iii) a third supply destination including a third pair of speakers including both the first pair of speakers (<NUM>, 21R) and the second pair of speakers (<NUM>, 22R);
a storage portion (<NUM>) that stores an optimal setting (Ia) in association with each of the first supply destination, the second supply destination, and the third supply destination, the optimal setting (Ia) stored in association with each of the first supply destination, the second supply destination, and the third supply destination being obtained by respectively measuring characteristics of the speakers (<NUM>, 21R, <NUM>, 22R) of the first supply destination, the second supply destination, and the third supply destination and; and
characterized by
the optimal setting (la) comprising at least one of a setting of frequency characteristics, a setting of output timing, and a setting of a volume level for optimizing the characteristics of the speaker according to the switching of the speaker; and
a signal processing portion (<NUM>) that reads out an optimal setting (la) from among optimal settings stored in the storage portion (<NUM>) in association with the first supply destination the second supply destination, and the third supply destination and uses the read-out optimal setting (la) to process a signal to be supplied to the speakers (<NUM>, 21R, <NUM>, 22R) of the first supply destination, the second supply destination, or the third supply destination according to the instruction for switching the supply destination received by the switching reception portion (<NUM>).