Industrial Research Limited

Google Inc.

Mark Alister Poletti

Neil L Scott

Terence Betlehem

Eugene Stytsenko

Provided are methods, systems, and apparatuses for recording a three-dimensional (3D) sound field using a vertically-oriented cylindrical array with multiple circular arrays at different heights. The design of the cylindrical array is well-suited to providing a high-resolution in azimuth and a reduced resolution in elevation, and offers improved performance over existing 3D sound reproduction systems. The methods, systems, and apparatuses provide a larger vertical aperture than horizontal aperture, as opposed to a spherical array, which has the same aperture for all dimensions, and further provides an alternative format to mixed-order spherical decomposition.

Cylindrical microphone array for efficient recording of 3D sound fields

A surround sound system for reproducing a spatial sound field in a sound control region within a room having at least one sound reflective surface. The system uses multiple steerable loudspeakers located about the sound control region, each loudspeaker having a plurality of different individual directional response channels being controlled by respective speaker input signals to generate sound waves emanating from the loudspeaker with a desired overall directional response. A control unit connected drives each of the loudspeakers and has pre-configured filters based on measured acoustic transfer functions for the room for filtering the input spatial audio signals to generate the speaker input signals for all the loudspeakers to generate sound waves with coordinated overall directional responses that combine together at the sound control region in the form of either direct sound or reflected sound from the reflective surface(s) of the room to reproduce the spatial sound field.

Surround sound system

A beam forming system includes one or more beam forming elements that are arranged to provide a non-planar doubly ruled radiation surface. The surface is defined by two families of rulings such that the length of the rulings within each family are configured to provide a radiation surface with substantially straight boundary edges, and the beam forming system is arranged to form acoustic beams.

Beam forming system and method

An in-line early enhancement generation system comprises one or more microphones positioned close to one or more sound sources so as to detect predominantly direct sound, an early reflection generation stage which generates a number of delayed reproductions of the microphone signals and which has unitary power gain whereby the stability of the system is independent of the delay times and amplitudes, and a number of loudspeakers placed to broadcast said early reflected energy into the room.

In-line early reflection enhancement system for enhancing acoustics

A musical instrument preamplifier system is provided which comprises a filtering means for splitting an input signal into two or more separate frequency bands comprising a similar phase response for each frequency band, two or more non-linear circuits, each of which distorts the input signal component of one of the frequency bands, and a summing network for recombining said frequency bands.

Guitar preamlifier system with controllable distortion

A circular transducer array () is provided for use in recording a sound field. The array () comprises a plurality of microphones (), a digital signal processor (), frequency compensation filters () and a sum and difference network (). The digital signal processor calculates the Fourier transform of sampled output signals from the transducers to produce a plurality of sound wave components specifying the sound field. The frequency compensation network () equalises each component using Bassel functions to flatten the apparent response of the array (30) and the sum and difference network () then combines the equalised components to provide a plurality of audio signals which represent the sound field.

Microphone arrays for high resolution sound field recording

A multi-channel reverberation system has a substantially constant multi-channel power gain at audio frequencies and comprises multiple signal inputs, one for each input channel, a number of comb filter networks connected to each signal input, each comb filter network including a feed forward stage, a cross-coupling network cross-coupling the comb filters to increase the reverberation echo density, and multiple signal outputs, one for each output channel. Preferably the feed forward stage of each comb filter provides a substantially constant multi-channel power gain at audio frequencies and the cross-coupling matrix is an orthogonal cross-coupling matrix cross-coupling a number of single channel allpass comb filters, positioned immediately before or after the delay lines, to create a multi-channel allpass comb filter with a unitary transfer function matrix at all frequencies.

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Wellington, New Zealand

Mark Alister Poletti