Abstract: Techniques are described for processing an audio signal to reduce the total harmonic distortion caused when it is reproduced by a loudspeaker, which is located within an audio reproduction device having an enclosure with an associated resonant frequency. After receiving the input audio signal, which includes the resonant frequency of the enclosure, the level of the input audio signal at the resonant frequency is reduced, thereby producing a first processed signal. In addition, the level of said input audio signal is reduced at all frequencies, producing a second processed signal. The first and second processed signals are combined to produce an output audio signal. The degree to which the level of the audio signal at both the resonant frequency and at all frequencies is reduced may be dependent upon the current volume level.

Abstract: An acoustic transducer (104) is shown, which may be configured as either a loudspeaker or a microphone. The acoustic transducer includes a magnet system (401), and a diaphragm (303) having a conductive element (402) disposed on it. The conductive element has a first outer conductive portion (405) and a second outer conductive portion (407) for generating force parallel to the magnet system. It also has a central conductive portion (406) for generating force normal to the magnet system. In this way, application of an audio frequency signal to the conductive element, possibly via positive and negative input terminals (202, 203), causes oscillation of the diaphragm.

Abstract: An acoustic transducer (104) is shown, which may be configured as either a loudspeaker or a microphone. The acoustic transducer includes a magnet system (401), and a diaphragm (303) having a conductive element (402) disposed on it. The conductive element has a first outer conductive portion (405) and a second outer conductive portion (407) for generating force parallel to the magnet system. It also has a central conductive portion (406) for generating force normal to the magnet system. In this way, application of an audio frequency signal to the conductive element, possibly via positive and negative input terminals (202, 203), causes oscillation of the diaphragm.

Abstract: Techniques are described for processing an audio signal to reduce the total harmonic distortion caused when it is reproduced by a loudspeaker, which is located within an audio reproduction device having an enclosure with an associated resonant frequency. After receiving the input audio signal, which includes the resonant frequency of the enclosure, the level of the input audio signal at the resonant frequency is reduced, thereby producing a first processed signal. In addition, the level of said input audio signal is reduced at all frequencies, producing a second processed signal. The first and second processed signals are combined to produce an output audio signal. The degree to which the level of the audio signal at both the resonant frequency and at all frequencies is reduced may be dependent upon the current volume level.

Abstract: A method of reproducing a stereo output signal (having a left field and a right field) represented as digital samples such that said stereo signal emulates the production of said audio signal from a specified audio source location relative to a listening source location (an indicated location). A left channel signal is produced by convolving an audio input signal with a broadband response file, selected from a plurality of stored files derived from empirical testing, dependant upon the indicated location. A right channel signal is also produced in this way. The left and right channel signals are each duplicated for playing through each of a plurality of displaced left field loudspeakers and displaced left field loudspeakers displaced right field loudspeakers respectively. Apparatus for reproducing a stereo output signal. A data storage facility having a stereo output signal.

Abstract: A method of processing an audio input signal represented as digital samples to produce a stereo output signal (having a left field and a right field) such that said stereo signal emulates the production of said audio signal from a specified audio source location relative to a listening source location. An audio input signal is received. An indication of an audio source location relative to a listening source location (an indicated location) is received. A broadband response file for each of the left field and the right field is selected from a plurality of stored files derived from empirical testing, dependant upon said indicated location. The audio input signal is convolved with each of the selected left field response file and the selected right field response file. Apparatus for processing an audio input signal.

Abstract: A method of producing a plurality of broadband response files derived from empirical testing on at least one human subject, for convolving with an audio input signal represented as digital samples to produce a stereo output signal (having a left field and a right field) such that the stereo signal emulates the production of said audio signal from a specified audio source location relative to a listening source location. A reference signal is derived for each of a plurality of test positions. An originating signal is derived from at least one reference signal. Each reference signal is deconvolved with the originating signal to produce a broadband response file for each test position. A data storage facility having a plurality of broadband response files stored therein.

Abstract: A method and apparatus for processing an audio signal to enhance the perceived lower frequency content of the audio signal when played through an audio output device, includes an input configured to receive an audio input signal, a processor configured to filter the audio input signal to produce a high frequency signal and a low frequency signal, generate an enhancement signal by producing higher frequency harmonics from the low frequency signal, including a process of self convolution, and combine the high frequency signal with the enhancement signal to produce an output signal; and an output configured to receive the output signal and produce an audio output.

Abstract: A method and apparatus for processing an audio signal to enhance the perceived lower frequency content of the audio signal when played through an audio output device, includes an input configured to receive an audio input signal, a processor configured to filter the audio input signal to produce a high frequency signal and a low frequency signal, generate an enhancement signal by producing higher frequency harmonics from the low frequency signal, including a process of self convolution, and combine the high frequency signal with the enhancement signal to produce an output signal; and an output configured to receive the output signal and produce an audio output.

Abstract: A method of producing a plurality of broadband response files derived from empirical testing on at least one human subject, for convolving with an audio input signal represented as digital samples to produce a stereo output signal (having a left field and a right field) such that the stereo signal emulates the production of said audio signal from a specified audio source location relative to a listening source location. A reference signal is derived for each of a plurality of test positions. An originating signal is derived from at least one reference signal. Each reference signal is deconvolved with the originating signal to produce a broadband response file for each test position. A data storage facility having a plurality of broadband response files stored therein.

Abstract: A method of processing an audio input signal represented as digital samples to produce a stereo output signal (having a left field and a right field) such that said stereo signal emulates the production of said audio signal from a specified audio source location relative to a listening source location. An audio input signal is received. An indication of an audio source location relative to a listening source location (an indicated location) is received. A broadband response file for each of the left field and the right field is selected from a plurality of stored files derived from empirical testing, dependant upon said indicated location. The audio input signal is convolved with each of the selected left field response file and the selected right field response file. Apparatus for processing an audio input signal.

Abstract: A method of reproducing a stereo output signal (having a left field and a right field) represented as digital samples such that said stereo signal emulates the production of said audio signal from a specified audio source location relative to a listening source location (an indicated location). A left channel signal is produced by convolving an audio input signal with a broadband response file, selected from a plurality of stored files derived from empirical testing, dependant upon the indicated location. A right channel signal is also produced in this way. The left and right channel signals are each duplicated for playing through each of a plurality of displaced left field loudspeakers and displaced left field loudspeakers displaced right field loudspeakers respectively. Apparatus for reproducing a stereo output signal. A data storage facility having a stereo output signal.