The present subject matter provides a technical solution to the technical problems facing sound localization by separating sounds and reproducing the separated sounds using a set of loudspeakers and a set of headphones. A general soundtrack that is meant to be experienced throughout the room would play through the loudspeakers, and specific sounds that are meant to be experienced near the listener would be played through a binaural representation in the headphones. The headphones may be selected to avoid occluding the ear, allowing sound produced at the loudspeakers to be heard clearly. This separation and reproduction of sounds using a combination of a loudspeaker and headphone provides a technical solution to the technical problem facing typical surround sound systems by localizing sounds for listeners in any location within a room. This improves reproduction accuracy of location-specific audio objects, including audio objects above or below a coplanar speaker configuration.

An audio system includes a transducer assembly, an optical sensing pathway, a laser, a detector assembly, and a controller. The transducer assembly is coupled to a user's ear and produces an acoustic pressure wave based on an audio instruction. The optical sensing pathway moves, at least in part, with a detected acoustic pressure wave. The laser emits light that is separated into a reference beam and a sensing beam that is coupled into the optical sensing pathway. The detected acoustic pressure wave interacts with the sensing beam to alter its optical path length. The detector assembly detects the reference and sensing beams from the optical sensing pathway, and measures the detected acoustic pressure wave based on changes in optical path length between the reference beam and the sensing beam. The controller adjusts the audio instruction based on the measurement of the detected acoustic pressure wave.

In some embodiments, virtualization methods for generating a binaural signal in response to channels of a multi-channel audio signal, which apply a binaural room impulse response (BRIR) to each channel including by using at least one feedback delay network (FDN) to apply a common late reverberation to a downmix of the channels. In some embodiments, input signal channels are processed in a first processing path to apply to each channel a direct response and early reflection portion of a single-channel BRIR for the channel, and the downmix of the channels is processed in a second processing path including at least one FDN which applies the common late reverberation. Typically, the common late reverberation emulates collective macro attributes of late reverberation portions of at least some of the single-channel BRIRs. Other aspects are headphone virtualizers configured to perform any embodiment of the method.

Embodiments relate to obtaining head-related transfer function (HRTF) through performing simulation using images of a user's head. The geometry of the user's head is determined based in part on one or more images of the user's head. The simulation of sound propagation from an audio source to the user's head is performed based on the generated geometry. The geometry may be represented in a three-dimensional meshes or principal component analysis (PCA)-based where the user's head is represented as a combination of representative three-dimensional shapes of test subjects' heads.

A method for processing an audio signal in accordance with a room impulse response is described. The audio signal is separately processed with an early part and a late reverberation of the room impulse response, and the processed early part of the audio signal and the reverberated signal are combined. A transition from the early part to the late reverberation in the room impulse response is reached when a correlation measure reaches a threshold, the threshold being set dependent on the correlation measure for a selected one of the early reflections in the early part of the room impulse response.

A headphone system includes a calibration microphone for performing a calibration routine with a user. The calibration microphone receives a stimulus signal emitted by the headphone system and generates a response signal indicating variations in the stimulus signal that arise due to physiological attributes of the user. Based on the stimulus signal and the response signal, the calibration engine generates response data. The calibration engine processes the response data based on a headphone transfer function (HPTF) associated with the headphone system in order to create an inverse filter that can reduce or remove acoustic variations caused by the headphone system. The calibration engine generates a personalized HRTF for the user based on the response data and the inverse filter. The personalized HRTF can be used to implement highly accurate 3D audio and is thereby well-suited for applications to immersive audio and audio-visual entertainment.

Systems and methods for providing improved localization of recorded and played back sound are provided by improved microphone arrays for recording sound and by improved systems for playback of sound. Microphone arrays include four microphones with sound transducers located and aimed to mimic capture of sound by human ears. Sound captured by two side-viewing microphones is attenuated, at the time of sound capture and/or recording, at a later processing stage, or at the time of sound playback, by low-pass filtering. The recording maintains four separate channels of sound. Playback occurs through four speakers arranged to reproduce sound in the way human ears hear sound, with appropriate attenuation for side speakers. Playback can also occur through four-channel headphones. Improved playback of two-channel stereo sound can also occur through low-pass filtering of each track and playing the filtered sound through side/rear speakers on the opposite sides.

According to the present disclosure, a sound output device includes: a sound acquisition part configured to acquire sound to be output to the other end of a sound guide part, one end of which is arranged near an entrance of an ear canal of a listener, the sound guide part having a hollow structure; and a head-related transfer function adjustment part configured to adjust a head-related transfer function of sound captured by the sound guide part. Since the head-related transfer function adjustment part adjusts the head-related transfer function of sound captured by the sound guide part, it is possible to listen to both ambient sound and sound provided from a sound output device such that the listener does not feel strangeness even in the state in which the listener is wearing the sound output device.

An audio headset may receive a plurality of audio signals corresponding to plurality of surround sound channels. The headset may determine, via its audio processing circuitry, context and/or content of the audio signals. The audio processing circuitry may process the audio signals to generate stereo signals carrying one or more virtual surround channels, wherein the processing comprises automatically controlling, based on the context and the content of the audio signals, a simulated acoustic environment of the virtual surround channels.

A public address method for live broadcast, in a helmet, of an audio signal conditioned from a plurality of raw audio channels, includes a pre-processing phase including the operations that consist of taking into account characteristics of the auditory perception of the listener; correcting each channel as a function of the characteristics of the auditory perception of the listener; a mixing phase including the production, from the channels thus pre-processed, of a mixed audio signal; a post-processing phase including the operations that consist of: measuring the sound level of a background noise; correcting the mixed audio signal as a function of the sound level of the background noise; a phase of reproducing, in the helmet, the conditioned audio signal resulting from post-processing.