Smart Speaker Ultrasonic Listening Area Mapping
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Solution Overview
Problem
The frequency response of speakers in rooms varies significantly as listeners move around due to room modes and acoustic effects, causing uneven sound balance and resonances at different frequencies.
Innovation Solution
A smart speaker device with a microphone array, non-transitory storage, and a controller that maps listening areas by using ultrasonic audio to identify device locations and apply filter settings to correct frequency response, creating a listening area response map for optimized sound quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the speaker operates in a room without location-based correction, then the device complexity is low, but the frequency response varies greatly as the listener moves around
Solution Approach 1:
The system performs preliminary measurement by playing test audio signals and capturing room responses at multiple predetermined locations before actual use. The controller stores these measurements and pre-calculates optimal filter settings for each location, creating a lookup table of correction parameters. During operation, the system simply retrieves and applies the appropriate pre-computed filters based on detected listener position, avoiding real-time complex calculations.
Solution Approach 2:
The system replaces physical acoustic correction devices (such as adjustable acoustic panels or multiple speaker systems) with electronic signal processing. The controller uses digital filters to dynamically adjust frequency response based on listener position, substituting mechanical/acoustic solutions with software-based correction that achieves the same goal of consistent sound quality throughout the room.
2Adaptability or versatility
If the system maps the entire listening area with multiple locations, then the frequency response correction coverage is improved, but the measurement and setup time increases
Solution Approach 1:
The system determines an optimal subset of measurement locations that provides sufficient coverage of the listening area without requiring exhaustive sampling of every possible position. The controller identifies key locations that capture the essential acoustic variations in the room, performing measurements at these strategic points rather than uniformly across the entire space, thus achieving adequate correction coverage with reduced measurement time.
3Measurement precision
If real-time location tracking is implemented, then the frequency correction accuracy is improved, but the processing requirements and device complexity increase
Solution Approach 1:
The system extracts only the essential location information needed for correction from the full audio signal data. The controller processes the captured audio to determine listener position with sufficient accuracy for applying the appropriate filter settings, without performing unnecessary complex analysis. The system retrieves only the relevant pre-computed filter parameters corresponding to the detected location, discarding extraneous data.
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
The solution ensures consistent and optimized sound quality across different locations within a listening area without requiring additional hardware, by using ultrasonic triangulation to determine device positions and applying real-time frequency corrections.
Implementation Method 1
identify a current location of a mobile device in the listening area based on ultrasonic audio received to the microphone array from the mobile device
Implementation Method 2
output frequency test audio from the loudspeaker to be received by the mobile device
Data Source
AI summary
A smart speaker device for acoustical listening area mapping and frequency correction includes a non-transitory storage configured to maintain a listening area response map indicating filter settings corresponding to each of a plurality of locations within a listening area, a microphone array, a loudspeaker; and a controller. The controller is programmed to execute a frequency correcting application to identify a current location of a mobile device in the listening area based on ultrasonic audio received to the microphone array from the mobile device, access the listening area response map to retrieve filter settings corresponding to the current location, and apply the filter settings to an audio stream to be output to the loudspeaker to correct for frequency response of the loudspeaker at the current location of the mobile device.