Capturing wide-band audio using microphone arrays and passive directional acoustic elements

An acoustic device comprising:

• one or more acoustic transducers;
• an array of multiple microphones disposed around the periphery of the acoustic device;
• a passive directional acoustic element disposed between at least two of the multiple microphones along the periphery of the acoustic device, the at least two of the multiple microphones being substantially aligned along a longitudinal axis of the passive directional acoustic element, the passive directional acoustic element comprising:
• a pipe having an elongated opening along at least a portion of the length of the pipe, and an acoustically resistive material covering at least a portion of the elongated opening, wherein one or more structural characteristics of the passive directional acoustic element is configured for capturing a target frequency range in accordance with a target beam-pattern associated with the array, the target beam-pattern being selected in accordance with a threshold amount of spatial aliasing;
• and one or more processing devices configured to process signals captured by the array.

A method comprising:

• receiving an input signal from an array of multiple microphones disposed around the periphery of an acoustic device, wherein the input signal includes acoustic signals received through a passive directional acoustic element disposed between at least two of the multiple microphones along the periphery of the acoustic device, the at least two of the multiple microphones being substantially aligned along a longitudinal axis of the passive directional acoustic element, the passive directional acoustic element including:
• a pipe having an elongated opening along at least a portion of the length of the pipe, and an acoustically resistive material covering at least a portion of the elongated opening, wherein one or more structural characteristics of the passive directional acoustic element are configured for capturing a target frequency range in accordance with a target beam-pattern associated with the array, the target beam-pattern being selected in accordance with a threshold amount of spatial aliasing;
• generating, by one or more processing devices from the input signal, a beamformed signal that represents signals captured by the array in accordance with one or more directional sensitivity patterns of the array;
• and generating an acoustic output signal based on the beamformed signal.

One or more machine-readable storage devices having encoded thereon computer readable instructions for causing one or more processing devices to perform operations comprising:

• receiving an input signal from an array of multiple microphones disposed around the periphery of an acoustic device, wherein the input signal includes acoustic signals received through a passive directional acoustic element disposed between at least two of the multiple microphones along the periphery of the acoustic device that are substantially aligned along a longitudinal axis of the passive directional acoustic element, the passive directional acoustic element including:
• a pipe having an elongated opening along at least a portion of the length of the pipe, and an acoustically resistive material covering at least a portion of the elongated opening, wherein one or more structural characteristics of the passive directional acoustic element are configured for capturing a target frequency range in accordance with a target beam-pattern associated with the array, the target beam-pattern being selected in accordance with a threshold amount of spatial aliasing;
• generating, by one or more processing devices from the input signal, a beamformed signal that represents signals captured by the array in accordance with one or more directional sensitivity patterns of the array;
• and generating an acoustic output signal based on the beamformed signal.