Abstract: An intelligent automatic volume control technique (100) for a communication device is provided that takes a measurement of the background audio environment at the time a user manually selects the volume (102, 104). A user preference is established for the volume setting relative to the background audio level being experienced (106). The informational relationship is stored and used for automatic volume control (108). When the background noise changes (110), the automatic volume control makes an intelligent decision on changing the volume (116). The current background noise level, the initial user volume setting and the background noise level when that volume was set are all used in the volume change decision making process.

Abstract: A vehicle seatback audio controller includes an entertainment interface that receives an entertainment audio signal from entertainment audio source, and a telematics interface that receives a telematics audio signal from a telematics audio source. The controller has an output that provides either the telematics audio signal to a seatback speaker when the telematics audio source is active or the entertainment audio signal to the seatback speaker when the telematics audio source is inactive. The controller may include an accelerometer or a microphone that generates a vibration signal and/or a noise signal. A level detector may receive the vibration signal and/or a noise signal, and adjust a level of the telematics audio signal to the seatback speaker as a function of the vibration signal and/or a noise signal.

Abstract: A multi-accessory vehicle audio system is providing that includes a plurality of vehicle audio accessories, the vehicle audio accessories generating a corresponding plurality of audio signals; and an audio switching device. The audio switching device includes an input section for receiving the audio signals from the vehicle audio accessories, a switching section operatively coupled to the input section for receiving the audio signals, a controller operatively coupled to the input section for receiving the audio signals and operatively coupled to the switching section for providing control signals to control the switching section and to regulate the output of the audio signals from the switching section according to an instruction set, and an output section operatively coupled to the switching section for receiving the regulated audio signals outputted from the switching section.

Abstract: An apparatus and method for automatically detecting an audio signal and sending a control signal are provided. The present invention is for automatically detecting an audio signal from a conventional IC, and controlling the power amplifier of the driving speaker or the switch of other external circuit. The apparatus at least includes an audio detection circuit and a reset/delay circuit. The audio detection circuit is connected to an audio signal from a conventional IC to detect the presence of the audio signal. The reset/delay circuit, after receiving an output signal from the audio detection circuit, can either reset the reset/delay circuit, or send a control signal after delaying for a period of time. The apparatus of the present invention can also be integrated into the external circuit, such as a power amplifier, to simplify the control to the external circuit by the conventional IC so as to switch off the external circuit to save power when there is no presence of the audio signal.

Abstract: One or more input channels are selected from among a plurality of input channels, and signals of the selected one or more input channels are mixed into a first output channel. A particular input channel to be excluded from the plurality of input channels is set as desired. Then, a setting is made such that the signals of the selected one or more input channels, having the signal of particular input channel excluded therefrom, are mixed into a second output channel. To the first output channel are set such signal paths as to allow mixing of all the signals of the selected one or more input channels. To the second output channel are set such signal paths as to allow mixing of the signals of the selected one or more input channels with the signal of the particular input channel excluded thereform.

Abstract: An audio control system may receive a plurality of audio input signals. A switch or multiplexer may switch one of the plurality of audio input signals from respective audio sources to a power amplifier. A controller in communication with the multiplexer may control switching of the multiplexer. A display may provide the user with information regarding the switching of the audio signal inputs. A user interface may permit the user to manually switch the audio source. A signal detector in communication with an audio input signal may detect a signal from a priority source. When the signal from the priority source is detected, the controller may direct the multiplexer to route the signal from the priority source to the power amplifier.

Abstract: An audio selection circuit. The audio selection circuit includes a control/switch circuit having a first input, a second input, and a first output, and a signal detector module configured to detect an audio signal on the second input. If the signal detector detects presence of the audio signal on the second input, the signal detector is configured to transmit a control signal to the control/switch circuit, and the control/switch circuit is configured in response to the control signal to disconnect the first input from the first output and to connect the second input to the first output. Otherwise, the control/switch circuit is configured to connect the first input to the first output and to disconnect the second input from the first output.

Abstract: A guitar amplifier having at least one channel, each channel having a differential amplifier with first and second amplifying members, each amplifying member having a control element, an electron emitting element and an electron collecting element, the electron emitting elements of the amplifying members commonly coupled and an output amplifier coupled to the differential amplifier and having an output terminal selectively coupled to the control element of the second amplifying member of the differential amplifier as a feedback path. An input terminal coupled to the control element of the first amplifying member and a user-adjustable presence control circuit selectively coupled between the control element of the first amplifying member and ground to increase the perceived brightness, when selected. The presence control circuit includes a high pass filter disposed between the input terminal and ground to filter a selected high frequency portion of the signal received at the input terminal.

Abstract: Members of a plurality of loud speakers receive control commands or signals via audio communication lines. The control commands, or, signals are responded to by those speakers which have been previously addressed.

Abstract: A sound system that may be used for a vehicle is provided. The system includes a head unit configured for generating an electrical signal, and a relay is configured to receive an electrical signal from the head unit. An interior speaker is carried by the vehicle and is configured for receiving an electrical signal from the relay in order to produce sound. An exterior speaker is carried by the vehicle and is configured for receiving an electrical signal from the relay in order to produce sound. A switch is configured to be opened and closed in order to trip the relay between a first state in which the interior speaker produces sound and the exterior speaker does not produce sound and a second state in which the interior speaker does not produce sound and the exterior speaker produces sound. A method of controlling a sound system is also provided.

Abstract: An intelligent solo-mute switching system for an audio signal processing device having a plurality of channels. A plurality of multi-throw momentary switches are monitored by a switch interface to detect at least three switch events. A channel state controller responds to the at least three switch events detected by the switch interface in directing a channel gain matrix to govern the plurality of channels.

Abstract: This is directed to a bend switch constructed from two substantially co-linear elongated bodies having opposing contact surfaces. In an open switch position, the contact surfaces remain apart, preventing electrical coupling. To close the switch, a user can bend the elongated bodies relative to each other to cause the contact surfaces to meet, thus creating an electrical coupling. Each elongated body can have several independent conductive portions. The bend switch can include a movable space member placed between the elongated bodies to maintain the contact surfaces a predetermined distance apart in the open switch position. The movable space member can include preferred or non-preferred bending orientations, equilibrium positions, and/or a potentiometer for closing the switch. The bend switch can control one or more functions (e.g., microphone, volume, or playback controls) of an electronic device (e.g., portable media device or cellular telephone) coupled to the bend switch.

Abstract: An electronic signal processor for processing signals includes a complex first filter, one or more gain stages and a second filter. The first filter is characterized by a frequency response curve that includes multiple corner frequencies, with some corner frequencies being user selectable. The first filter also has at least two user-preset gain levels which may be alternately selected by a switch. Lower frequency signals are processed by the first filter with at least 12 db/octave slope, and preferably with 18 db/octave slope to minimize intermodulation distortion products by subsequent amplification in the gain stages. A second filter provides further filtering and amplitude control. The signal processor is particularly suited for processing audio frequency signals.

Abstract: Two different and separate audio data streams are processed through a personal computer (PC) system or other computing device so that the separate and distinct audio data streams are heard through separate sound transducers. In a preferred embodiment, chat messages received over a network during execution of a multiplayer game are processed separately from sounds produced by the multiplayer game, enabling a user to hear the game sounds from speakers, separate and distinct from verbal chat messages, which are heard through earphone(s). The earphone(s) are included in a headset, as well as a microphone that enables the user to produce verbal data that are conveyed to a hardware control unit that is connected to the PC system through a universal serial bus (USB) port. The chat audio data are converted into an analog audio signal that is heard by the user in the headphone(s) and is spatially separate and distinct from the game audio data heard through the speakers.

Abstract: An audio device protection system for use in an electronic device electrically connecting to an audio device is disclosed. The electronic device outputs an audio signal, a power on/off signal, and a trigger signal. The audio device protection system includes a switching unit electrically connected to the audio signal and the audio device and a control unit electrically connected to the trigger signal and the switching unit. The control unit outputs, upon receipt of the trigger signal, a control signal to control electrical connection/disconnection of the audio signal to/from the audio device by the switching unit, thus controlling timing of delivery of the electronic device-outputted audio signal to the audio device during a startup/shutdown procedure of the electronic device. Accordingly, switching on/off a power of the electronic device does not generate audio noise which may otherwise instantaneously trigger or shut down the audio device to the detriment thereof.

Abstract: Embodiments of the present invention include switching amplifier circuits and methods. In one embodiment, the present invention includes an audio amplification method comprising modulating an audio input signal to produce a first modulated signal and a second modulated signal, amplifying the first modulated signal to generate an amplified first modulated signal at a first output terminal of an amplifier, and amplifying the second modulated signal to generate an amplified second modulated signal at a second output terminal of the amplifier, wherein the first output terminal of the amplifier is constant when the second output terminal of the amplifier is switching, and wherein the second output terminal of the amplifier is constant when the first output terminal of the amplifier is switching.

Abstract: The programmable analog input/output integrated circuit system includes a plurality of integrated circuit pins, an analog input/output circuit, a control module, and a switching module. The analog input/output circuit is coupled to the plurality of pins and determines the input/output status of each of the pins. The control module generates an I/O control signal and a switching control signal based on the input/output status of the integrated circuit pins. The I/O control signal is provided to the analog I/O circuit, which configures itself as an input or output based on the I/O control signal. The control module provides the switching control signal to the switching module, which configures itself to couple the analog input and/or analog output to corresponding functional circuitry of the corresponding integrated circuit.

Abstract: A robot includes first and second microphones and movable portions. The first microphone gathers a first sound reception signal by gathering mainly a target signal. The second microphone gathers a second reception sound signal by gathering mainly noise other than the target signal. The movable portions operate on the basis of the first sound reception signal output from the first microphone and the second sound reception signal output from the second microphone.

Abstract: The illustrative embodiments provide a method and system for automatically muting a headphone. The headphone detects a sound external to the headphone. A volume threshold and a frequency threshold are received, wherein the volume threshold and the frequency threshold define a sound of interest. A determination is made as to whether the sound external to the headphone is the sound of interest. Responsive to a determination that the sound external to the headphone is the sound of interest, a signal is transmitted to automatically mute an active state of the headphone.

Abstract: A system and method for flexibly outputting audio from a plurality of programs to the particular outputs that are desired for each audio stream. This routing flexibility enables the audio system to operate in a variety of configured usage modes, wherein each usage mode identifies the routing of each audio stream to one or more outputs such as SPDIF, HDMI, I2S, and DAC.

Abstract: The audio player is configured to be attached to a gift. In one embodiment, the audio player contains an electric circuit including a battery, a switch, an audio memory and loudspeaker in a series circuit. The switch is held open by a card positioned in a slot in the body of the audio player. The card usually contains the gift giver's and gift recipient's names and may contain a written sentiment. When the card is removed from the slot the switch is closed so that the memory produces a sequential signal. This is transformed by the loudspeaker into audible sound. The audible sound is a verbal or musical greeting, which may correspond to the occasion for which the gift is being presented. Other electrical and mechanical embodiments are disclosed.

Abstract: A system and method are presented for identifying, in an electrical device having an audio interface port, a headset type. The system includes a microcontroller logic unit with an output, connected to a test network, to supply a test voltage. The test network also is connected to the audio interface port. The test network can include combinations of resistors, capacitors, and switches. A voltage determination sub-system has an input connected to the interface port line and an output to supply a determination signal responsive to voltage at the audio interface port. The logic unit has an input connected to the determination sub-system output and compares determination signal values with a predetermined threshold value to identify a headset type connected to the audio interface port.

Abstract: When selecting a specific input source that can be processed by only a second voice-data processing unit instead of an input source currently being processed by a first voice-data processing unit, a voice-data processing circuit selects and delivers an input source selected by a second analog switch to the first voice-data processing unit by using a first analog switch. Then, after the first and second voice-data processing units simultaneously process the identical input source other than the specific input source over a certain time period, the second analog switch selects and delivers the specific input source to the second voice-data processing unit and a first switch selects an output of the second voice-data processing unit and outputs a voice of the specific input source as an analog audio output.

Abstract: Noise generation is reduced further. Oscillation control circuit 11 generates a modulation signal modulating oscillation frequency of an oscillation signal generated by oscillation circuit 12 and outputs modulation signal to same. Preferably, the modulation signal fluctuates period of the oscillation signal sequentially. The oscillation circuit 12 is composed of a ring oscillator, for example, and the power supply voltage or power supply current of the ring oscillator is controlled to fluctuate sequentially by the modulation signal output from the oscillation circuit 11. Buffer 14 of charge pump circuit 13 generates signals/? and ? by the oscillation signal and drives capacitors C1 and C2 for supplying a higher voltage than the voltage of the power supply Vcc to gate of N-channel MOSFET Q1.

Abstract: An impedance selection circuit for the connection of multiple circuit braches is disclosed. The connection is supplied with the use of three switching jacks and connects directly to the branches through two jacks, or combines the branches in parallel or series to output to one jack. This circuit design comprises a low impedance jack 1, a middle impedance jack 2, and a high impedance jack 3. These jacks will connect to the multiple circuit branches individually, in series, or in parallel. In an example of using the impedance selection circuit, the user can implement the circuit to connect an amplifier to a multi-speaker array at three different impedances. The low impedance jack 1 yields a connection at a smallest fraction of the individual speakers' impedance. The middle impedance jack 2 yields a connection at a larger fraction such as one half the individual speakers' impedance. The high impedance jack 3 yields a connection at a higher impedance such as the same impedance as each individual speaker.

Abstract: Even when both a digital audio signal and an analog audio signal are inputted, a type of inputted digital audio signal is identified, and an internal signal path is automatically switched based on the result of the identification operation and previously set content. A main storage of a host microcomputer 12 stores signal path information indicating a signal path to be selected for each type of digital audio signal inputted from each external AV apparatus. A DIR 3 identifies the type of digital audio signal inputted from a digital input terminal 1. The host microcomputer 12 switches an A/D switching selector 4 and an analog direct/DSP process switching selector 7 respectively so that a signal path corresponding to the type of signal shown in the result of an identification operation of the DIR 3 is selected, based on the signal path information.

Abstract: Systems and techniques for controlling a surround sound system having multiple input signals and multiple spatially diverse transducers may include defining a first control region and a second control region. When operating in the first control region, a first set of functions is performed. For example, for each of the spatially diverse transducers, an input signal may be selected, a relative strength of the selected input signal may be adjusted, and the adjusted input signal may be applied to the transducer. When operating in the second control region, a second set of functions is performed. For example, for each of the spatially diverse transducers, two or more input signals may be selected, a relative strength of the selected input signals may be adjusted, the adjusted input signals may be mixed, and the mixed input signals may be applied to the transducer.

Abstract: An audio control system with a hot plug-and-play mechanism and a method thereof, which can effectively solve the defects that devices of a conventional high definition audio specification must be fixed on a mother board and cannot be hot plugged and played so that the convenience and the time efficiency in use can be enhanced. The audio control system includes an audio controller, a first audio encoder/decoder and a second audio encoder/decoder. The audio controller has a first reset signal and a second reset signal. The first audio encoder/decoder is coupled to the audio controller and receives the first reset signal. The second audio encoder/decoder is coupled to the audio controller and receives the second reset signal. The hot plug-and-play mechanism can be achieved when the audio controller selectively enables the first reset signal or the second reset signal.

Abstract: The method and apparatus are provided for several audio signal processing apparatuses to share at least one audio output device. Several audio signals sent from the audio signal processing apparatuses are received. The DC levels of the audio signals are shifted to a predetermined value. One of the adjusted audio signals is then selected for signal-transmitting to the audio output device. Afterwards, the DC level of the selected audio signal is re-adjusted to the predetermined value.

Abstract: A portable wireless terminal provides a signal output circuit for outputting an audio signal to a speaker or to earphones from an earphone jack via a plug, and a controller for controlling the signal output circuit to output an arbitrary audio signal or another audio signal to the speaker and/or the earphones at an arbitrary timing when the audio signal is being outputted to the speaker and/or the earphones. Thereby, an audio signal can be outputted to the desired speaker and/or the earphones that have been arbitrary selected by switching the signal output circuit without pulling the plug out of the earphone jack when the audio signal is being outputted to the speaker and/or the earphones.

Abstract: A audio codec includes a first analog to digital converter for producing a first one-bit data stream, a second one-bit data stream is received from a digital microphone. A selection module produces a one-bit output signal that is the first one-bit data stream when a selection signal is in a first state, and produces a the one-bit output signal that is the second one-bit data stream when the selection signal is in a second state. A decimation and filter module produces a down sampled signal based on the one-bit output signal.

Abstract: Herein disclosed is an audio signal processing apparatus comprising first audio signal processing means for processing an audio signal within a first process time; second audio signal processing means for processing the audio signal within a second process time which is different from the first process time; audio signal delaying means for delaying the audio signal in response to each of the first process time of the first audio signal processing means and the second process time of the second audio signal processing means; selecting means for selectively receiving the audio signals respectively processed by the first and second audio signal processing means; and audio signal outputting means for selectively outputting the audio signal selectively received by the selecting means and the audio signal delayed by the audio signal delaying means.

Abstract: The telephone apparatus of the present invention comprises a first voice band expander for generating a voiced signal frequency component by shifting the frequency of the voice signal received, a second voice band expander for generating a voiceless signal frequency component by shifting the frequency of the voice signal received, and a voice composer for composing the voice signal received, the output of the first voice band expander, and the output of the second voice band expander, which is able to output clear voices in aural communication.

Abstract: In an apparatus which estimates characteristics of a surrounding noise only when an input signal is soundless and performs a noise reduction or suppression of the input signal based on the estimated result, a signal noise ratio is estimated from the input signal, and an automatic switch or an automatic adjustment is performed so as to execute a noise reduction only when the signal noise ratio is good, otherwise to avoid the noise reduction or make the noise reduction degree smaller.

Abstract: An entertainment system mounted on a vehicle comprises a plurality of audio sources. The entertainment system further comprises a head unit provided in the front seat area and a rear controller provided in the rear seat area. The head unit includes a control switch for switching between front control and rear control. The front control selects a front audio source to be played in the front seat area and controls the selected front audio source. The rear control selects a rear audio source to be played in the rear seat area and controls the selected rear audio source. Thus, a front user can operate the rear audio source. The head unit further includes an enabling switch for switching between an enabled state in which operation of the rear controller is enabled and a disabled state in which operation of the rear controller is disabled. Thus, audio operation by a rear user can be restricted.

Abstract: The invention relates to a Muting Circuit used to control the path of signal flow for the amplified audio signals from an audio CODEC in a dual audio subsystem. More specifically, to the muting control of the rear and front panel head phone/line out and microphone connectors for the audio subsystem of a standard PC system. The present invention implements muting on the headphone 1 line-out jacks while allowing the Front Audio Board to be optional without the need for jumpers.

Abstract: The invention provides a component selection control system comprising signal output components 2 to 5, signal input components 4, 5, and an amplifier unit 1 having these components 2 to 5 connected thereto. The signal output components 2 to 5 have respective on-off switches 23, 33, 44, 54 provided on signal output lines 73 to 76 for delivering audio signals to the amplifier unit 1 therethrough, and the amplifier unit 1 has a common input terminal g. The signal output lines 73 to 76 of the output components 2 to 5 are connected to one another at a point connected to a common signal line 71, which is connected to the common input terminal g of the amplifier unit 1. This arrangement greatly reduces the numbers of signal lines and terminals required for connecting the components 2 to 5 to the amplifier unit 1.

Abstract: In a signal processing system with an IC having an intrinsic signal provided at a pin of the IC, a first operational function (de-emphasis) for the signal is provided at the pin, and further along in the signal flow path, a second operational function (variable attenuation) for the signal is provided within the IC. An extrinsic signal is switchably coupled to the pin so that the second operational function can be used to operate on the extrinsic signal. The second signal is coupled to the pin at a low source impedance so that when the second signal is switched to be operational, the first operational function is defeated, and the first signal is severely attenuated. When the circuit is switched to not couple the second signal to the pin, the coupling path for the second signal and the low source impedance are both removed, thus restoring the first operational function and the first signal at the pin of the IC.

Abstract: This invention provides a speaker system that minimizes the number of wires used to provide power and audio signal to all of the speakers. This is accomplished by without generating interference noises from shared signal wire implementations. The invention also provides a methodology for reducing power signals from being transmitted to headphones inserted into a headphone jack. The invention may use four wires to operate the speaker system. A first wire may be used to provide the control data signal common and control power common, and, if a headphone is used, the first wire may also serve as a common ground connection for the earpieces in the headphone. The second wire may provide a substantially constant current, so that constant current may be carried in the first wire regardless of the voltage on the second power/data wire. This way, the first wire may serve as a common control circuitry and the headphone as well.

Abstract: An audio amplifier configuration for a personal computer system optimizes performance in both the single-ended mode and the bridged mode. In a single-ended mode, as when the computer system user receives audio through headphones plugged into an external jack, a jack sense line is activated that switches into operation a power supply that is optimized for single-ended audio operation. In the bridged mode, as when the computer user receives audio from the system's internal speaker, operation is such that the audio amplifier is supplied by a power source optimized for operation in a bridged mode. In general, single-ended operation dictates that the audio amplifier power supply exhibit substantial noise immunity characteristics; whereas bridged-mode operation requires that the power supply be capable of supplying more demanding peak voltage and current excursions.

Abstract: A sound control system includes a plurality of electronic devices connected to a communication network, each of the electronic devices being capable of independently producing sound from connected speakers, and a sound control device transmitting control signals for controlling the electronic devices and audio signals to the electronic devices via the communication network. Each electronic device includes receiving means for receiving the control signals and the audio signals via the communication network, and selecting means for switching from other external signals to the audio signals in response to the control signals in order to drive the speakers by only the audio signals output to the speakers.

Abstract: A method and system are disclosed for controlling pop noises in a sound broadcasting system. After controllably connecting an output of a drive amplifier to a first predetermined low voltage level through a first switch, a first portion of an operation control data set is input to a digital-to-analog converter (DAC) circuit for driving an output thereof to a second predetermined low voltage level, and a second portion of the operation control data set is also input to the DAC circuit and further to the drive amplifier to bring the output of the drive amplifier to a common mode voltage level over a predetermined rise-up time period for controlling the pop noises.

Abstract: A reconfigurable speaker system for producing sound in response to at least one of right and left channel audio signals generated by an audio source. The speaker system can be configured by the user to simultaneously reproduce right and left channel audio information from a single speaker, or the speaker system can be configured to reproduce right and left channel audio information independently from a pair of speakers. The speaker system includes a dual voice coil woofer and a pair of independent tweeters. A switch device is provided in circuit with the woofer and pair of tweeters so that in one position of the switch device, the dual voice coil woofer is configured to produce sound in response to both of the right and left channel audio signals, and each tweeter in the tweeter pair is configured to produce sound in response to a respective one of the right and left channel audio signals.

Abstract: A dual purpose loudspeaker incorporating at least two audio signal inputs and at least one switch is adapted to receive and reproduce either a single audio signal input or two audio signal inputs according to the position of the switch. A switch slide mechanically linked to the switch is provided which blocks one of the audio signal inputs when the switch is in the single-channel position, thereby preventing erroneous connection to the blocked audio signal input.

Abstract: Techniques for configuring multiple audio transducers, including telephony devices, are provided. Audio configurations for the multiple audio input and output transducers can be selected by the user. When it is determined that a telephony device has gone off hook, the audio configuration is changed to utilize the off hook telephony device. When the telephony device goes on hook, the audio configuration can be returned to its original state. The present invention allows multiple audio input and output transducers to be used, for example, in a computer telephony client by efficiently switching between these transducers via configuration changes. According to specific embodiments, the present invention may be provided in an audio transducer switch between the multiple audio transducers and a sound card of a computer, or within a sound card itself.

Abstract: Better reproduction of sound is achieved analyzing audio signals for perceptual soundfield imaging cues, and applying appropriate portions of the audio signal to a directional speaker and to a diffusing speaker, based on the analyzed audio signals. Specifically, the audio signal is applied to a critical band filter bank, and at the higher frequencies a detector detects leading edges in the signal's envelope. Concurrently, the audio signal is applied to a delay element followed by a reconstruction filter bank. The output of each filter in the reconstruction filter bank is applied to a one-input/two-outputs soft switch (single pole, double throw) that is controlled by one or more of the detectors. One output of the switch is applied to a directional speaker, and the other output of the switch is applied to a diffusing speaker.

Abstract: A first selector switch outputs a second audio signal of m channel corresponding to a selected second zone to a power amplifier of the m channel and a second selector switch couples output of the power amplifier of the m channel to a speaker terminal for the selected second zone whereby an audio signal can be supplied to either one of a plurality of second zones. In one aspect of the invention, a first selector switch outputs a second audio signal of m channel corresponding to a selected second zone to a power amplifier of the m channel determined by a control section and a second selector switch couples output of the m channel determined by the control section to a speaker terminal for the selected second zone whereby an audio signal can be supplied to one or more zones among plural second zones.

Abstract: An earphone apparatus is designed for an audio device and a portable communication terminal device. The earphone apparatus includes a first plug for disconnectable connection with the audio device, and a second plug for disconnectable connection with the portable communication terminal device. An electroacoustical transducer connected to the first plug and the second plug is operative for converting a first electric signal transmitted via the first plug into corresponding sound, and for converting a second electric signal transmitted via the second plug into corresponding sound. A suitable controller provided between the first plug and the electroacoustical transducer is operative for controlling a level of the first electric signal transmitted to the electroacoustical transducer.

Abstract: A computing device allows selective output of audio signals within a frequency band. The computing device has a main system having an audio signal generator generating audio signals, a main audio outputting unit attached to the main system and outputting the generated audio signals, an auxiliary system connected to the main system and receiving the audio signals generated by the audio signal generating unit, and an auxiliary audio outputting unit attached to the auxiliary system and outputting the audio signals received in the auxiliary system A switching unit controls the audio signals to pass through a plurality of selectable filters filtering the audio signals within respective frequency bands and to supply the selected filtered audio signals to the main audio outputting unit, and to the auxiliary audio outputting unit, depending upon whether the auxiliary system is connected to the main system.

Abstract: A sound collecting device is provided which is designed to minimize adverse effects on an output caused by exposure of an electroacoustic transducer to the air. The device includes an electroacoustic transducer and a vibrating circuit. The transducer is exposed to the air and responsive to input of a sound wave to produce a corresponding acoustic signal. The vibrating circuit vibrates the transducer to shake foreign substances such as dust or drops of water from the transducer. In a modified form, an electromagnetic sensor is provided which measures an electromagnetic noise transmitted to the transducer and which removes the electromagnetic noise from an output of the transducer to produce a noiseless acoustic signal.