Abstract: Techniques for synthesizing a parameterized haptic track from a multichannel audio signal and embedding the haptic track in a multichannel audio codec bit stream. The haptic track synthesis can occur while encoding the multichannel audio signal as the multichannel audio codec bit stream. The haptic track can be synthesized in a way that allows select parameters of the haptic track to be extracted from the audio signal. The parameters can be adjusted by a user during the encoding process. For example, the parameter adjustments can be made using a authoring/monitoring tool. The parameter adjustments can be recorded as metadata that, along with the haptic track, is included in the codec bit stream. In some aspects the present technology, the adjustable parameters include center frequency, gain, decay rate, and other parameters that allow for modulation of the haptic track during decoding of the codec bit stream.

Abstract: Embodiments are described for rendering spatial audio content through a system that is configured to reflect audio off of one or more surfaces of a listening environment. The system includes an array of audio drivers distributed around a room, wherein at least one driver of the array of drivers is configured to project sound waves toward one or more surfaces of the listening environment for reflection to a listening area within the listening environment and a renderer configured to receive and process audio streams and one or more metadata sets that are associated with each of the audio streams and that specify a playback location in the listening environment.

Abstract: Embodiments are directed to speakers and circuits that reflect sound off a ceiling to a listening location at a distance from a speaker. The reflected sound provides height cues to reproduce audio objects that have overhead audio components. The speaker comprises upward firing drivers to reflect sound off of the upper surface and represents a virtual height speaker. A virtual height filter based on a directional hearing model is applied to the upward-firing driver signal to improve the perception of height for audio signals transmitted by the virtual height speaker to provide optimum reproduction of the overhead reflected sound. The virtual height filter may be incorporated as part of a crossover circuit that separates the full band and sends high frequency sound to the upward-firing driver.

Abstract: Embodiments are described for a system of rendering object-based audio content through a system that includes individually addressable drivers, including at least one driver that is configured to project sound waves toward one or more surfaces within a listening environment for reflection to a listening area within the listening environment; a renderer configured to receive and process audio streams and one or more metadata sets associated with each of the audio streams and specifying a playback location of a respective audio stream; and a playback system coupled to the renderer and configured to render the audio streams to a plurality of audio feeds corresponding to the array of audio drivers in accordance with the one or more metadata sets.

Abstract: Techniques for synthesizing a parameterized haptic track from a multichannel audio signal and embedding the haptic track in a multichannel audio codec bit stream. The haptic track synthesis can occur while encoding the multichannel audio signal as the multichannel audio codec bit stream. The haptic track can be synthesized in a way that allows select parameters of the haptic track to be extracted from the audio signal. The parameters can be adjusted by a user during the encoding process. For example, the parameter adjustments can be made using a authoring/monitoring tool. The parameter adjustments can be recorded as metadata that, along with the haptic track, is included in the codec bit stream. In some aspects the present technology, the adjustable parameters include center frequency, gain, decay rate, and other parameters that allow for modulation of the haptic track during decoding of the codec bit stream.

Abstract: A method for enhancing speech includes extracting a center channel of an audio signal, flattening the spectrum of the center channel, and mixing the flattened speech channel with the audio signal, thereby enhancing any speech in the audio signal. Also disclosed are a method for extracting a center channel of sound from an audio signal with multiple channels, a method for flattening the spectrum of an audio signal, and a method for detecting speech in an audio signal. Also disclosed is a speech enhancer that includes a center-channel extract, a spectral flattener, a speech-confidence generator, and a mixer for mixing the flattened speech channel with original audio signal proportionate to the confidence of having detected speech, thereby enhancing any speech in the audio signal.

Abstract: Method and system for generating output signals for reproduction by two physical speakers in response to input audio signals indicative of sound from multiple source locations including at least two rear locations. Typically, the input signals are indicative of sound from three front locations and two rear locations (left and right surround sources). A virtualizer generates left and right surround outputs useful for driving front loudspeakers to emit sound that a listener perceives as emitting from rear sources. Typically, the virtualizer generates left and right surround outputs by transforming rear source inputs in accordance with a head-related transfer function. To ensure that virtual channels are well heard in the presence of other channels, the virtualizer performs dynamic range compression on rear source inputs. The dynamic range compression is preferably accomplished by amplifying rear source inputs or partially processed versions thereof in a nonlinear way relative to front source inputs.

Abstract: A perceptually motivated, frequency domain active matrix decoder and decoding method which decodes N audio input signals to generate M audio output signals, where M is greater than N, including by generating M streams of output frequency components which determine the audio output signals, in response to N streams of input frequency components indicative of the audio input signals, determining power ratios from the input frequency components without use of feedback, including at least one power ratio for each critical frequency band in a set of critical frequency bands, and determining gain control values for each of the critical frequency bands from the power ratios including by shaping the power ratios in nonlinear fashion without use of feedback. An active matrix element is steered using the gain control values.

Abstract: A method for determining an inverse filter for altering the frequency response of a loudspeaker so that with the inverse filter applied in the loudspeaker's signal path the inverse-filtered loudspeaker output has a target frequency response, and optionally also applying the inverse filter in the signal path, and a system configured (e.g., a general or special purpose processor programmed and configured) to determine an inverse filter. In some embodiments, the inverse filter corrects the magnitude of the loudspeaker's output. In other embodiments, the inverse filter corrects both the magnitude and phase of the loudspeaker's output. In some embodiments, the inverse filter is determined in the frequency domain by applying eigenfilter theory or minimizing a mean square error expression by solving a linear equation system.

Abstract: A perceptually motivated, frequency domain active matrix decoder and decoding method which decodes N audio input signals to generate M audio output signals, where M is greater than N, including by generating M streams of output frequency components which determine the audio output signals, in response to N streams of input frequency components indicative of the audio input signals, determining power ratios from the input frequency components without use of feedback, including at least one power ratio for each critical frequency band in a set of critical frequency bands, and determining gain control values for each of the critical frequency bands from the power ratios including by shaping the power ratios in nonlinear fashion without use of feedback. An active matrix element is steered using the gain control values.

Abstract: A method for determining an inverse filter for altering the frequency response of a loudspeaker so that with the inverse filter applied in the loudspeaker's signal path the inverse-filtered loudspeaker output has a target frequency response, and optionally also applying the inverse filter in the signal path, and a system configured (e.g., a general or special purpose processor programmed and configured) to determine an inverse filter. In some embodiments, the inverse filter corrects the magnitude of the loudspeaker's output. In other embodiments, the inverse filter corrects both the magnitude and phase of the loudspeaker's output. In some embodiments, the inverse filter is determined in the frequency domain by applying eigenfilter theory or minimizing a mean square error expression by solving a linear equation system.

Abstract: Method and system for generating output signals for reproduction by two physical speakers in response to input audio signals indicative of sound from multiple source locations including at least two rear locations. Typically, the input signals are indicative of sound from three front locations and two rear locations (left and right surround sources). A virtualizer generates left and right surround outputs useful for driving front loudspeakers to emit sound that a listener perceives as emitting from rear sources. Typically, the virtualizer generates left and right surround outputs by transforming rear source inputs in accordance with a head-related transfer function. To ensure that virtual channels are well heard in the presence of other channels, the virtualizer performs dynamic range compression on rear source inputs. The dynamic range compression is preferably accomplished by amplifying rear source inputs or partially processed versions thereof in a nonlinear way relative to front source inputs.

Abstract: A method for enhancing speech includes extracting a center channel of an audio signal, flattening the spectrum of the center channel, and mixing the flattened speech channel with the audio signal, thereby enhancing any speech in the audio signal. Also disclosed are a method for extracting a center channel of sound from an audio signal with multiple channels, a method for flattening the spectrum of an audio signal, and a method for detecting speech in an audio signal. Also disclosed is a speech enhancer that includes a center-channel extract, a spectral flattener, a speech-confidence generator, and a mixer for mixing the flattened speech channel with original audio signal proportionate to the confidence of having detected speech, thereby enhancing any speech in the audio signal.

Abstract: The disclosure includes description of a method of noise reduction according to one possible implementation. An audio signal is sampled at a sample rate f. The audio signal is converted to a digital signal in the time domain. For each of a series of frames of time, the digital signal in the time domain is converted to a digital signal in frequency domain for the frame of time. The converting includes determining a set of frequency domain values. The frequency domain values in the set are created by a set of digital filters, and the digital filters are related to each other by a constant ratio of filter bandwidth to center frequency, related to a perceptual scale for audio processing. A set of minimum magnitude frequency domain values is obtained. These values include, at each frequency represented by the frequency domain values, a frequency domain value having a minimum magnitude from among frequency domain values for such frequency over a time interval spanning multiple frames of time.

Abstract: Load correction systems and methods. In one embodiment, the load correction system includes an audio source signal and a parametric equalizer coupled to receive the source signal. A summation is configured to combine an inverse of the source signal with an output of the equalizer. An amplifier is configured to receive an output of the summation, and a speaker is coupled to receive an output of the amplifier. According to an embodiment, the equalizer comprises an adjustable equalizer. According to another embodiment, a digital signal processor implements the equalizer and summation. According to yet another embodiment, in absence of the filter, a combination of the speaker and electronic components coupled with the speaker have a larger amount of phase at low frequencies and a smaller amount of phase at high frequencies.