Spherical Audio Device Speaker Microphone Arrangement
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Solution Overview
Problem
Existing audio conference devices with integrated speakers and microphones face challenges in minimizing wraparound sound, leading to a heavy processing burden on echo cancellers and compromising the signal-to-noise (S/N) ratio due to the close proximity of speaker and microphone components.
Innovation Solution
A sound emission and collection device is designed with unidirectional microphones arranged on one circumference and speakers on an opposite circumference, optimizing their directivities to minimize wraparound sound, and incorporating signal processing means to enhance the S/N ratio by estimating sound source direction and selectively outputting signals with the highest sound pressure levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the speaker and microphone are placed close to each other for a compact configuration, then the device size is reduced, but the wraparound sound from the speaker to the microphone increases
Solution Approach 1:
The patent transitions from a planar arrangement to a three-dimensional spherical configuration. The speaker and microphone are positioned on the surface of a sphere with the user at the center, utilizing the third dimension (radial distance) to separate components while maintaining compact overall device volume. This spatial reconfiguration increases the sound propagation path length without significantly increasing the device's external dimensions.
Solution Approach 2:
The patent employs asymmetric positioning where the speaker and microphone are placed at different locations on the spherical surface, specifically arranged to maximize the distance between them relative to the user's position. This asymmetric arrangement ensures that the direct sound path from speaker to microphone is lengthened, reducing wraparound effects while maintaining the compact spherical form factor.
2Device complexity
If the speaker and microphone are placed close to each other, then the device configuration is simplified, but the processing burden on the echo canceller increases
Solution Approach 1:
The patent implements preliminary acoustic isolation by strategically positioning the speaker and microphone on the spherical surface before sound propagation occurs. This pre-configured spatial arrangement creates inherent acoustic separation that reduces the amount of echo requiring digital processing, thereby decreasing the computational burden and processing time required by the echo canceller algorithm.
3Volume of moving object
If the speaker and microphone are placed close to each other, then the device can be miniaturized, but the S/N ratio deteriorates
Solution Approach 1:
By utilizing the radial dimension of the spherical configuration, the patent increases the distance between the speaker sound source and the microphone receiver along the sound propagation path. This three-dimensional arrangement effectively lengthens the path that wraparound sound must travel, allowing the microphone to better distinguish direct user speech from reflected speaker sound, thereby improving the signal-to-noise ratio while maintaining a compact device footprint.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration effectively suppresses wraparound sound and improves the S/N ratio by lengthening the propagation path of unwanted sound, allowing for a compact device design while maintaining high sensitivity to vocalized sounds and significantly reducing echo.
Implementation Method 1
a plurality of unidirectional microphones arranged toward a center on a circumference of a first circle in which one axis is set as the center; and a plurality of speakers arranged toward a direction opposite the center on a circumference of a second circle in which the axis is set as the center
Data Source
AI summary
A sound emission and collection device has a plurality of speakers (11) and a plurality of microphones. The speakers each have a sound emission surface arranged on the side surface of a case (1) so that sound can be emitted in all circumferential directions. The microphones (12) each are arranged with the sound collection direction set in the center direction of the case (1). The microphone (12) and the speaker (11) have directivities opposing to each other to minimize a wraparound sound from the speaker (11) to the microphone (12). Moreover, since the speaker (11) and the microphone (12) are arranged on circumferences of concentric circles, it is possible to obtain a compact configuration.