Spread Spectrum Audio Sync for Dumb and Smart Speakers
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Solution Overview
Problem
Conventional smart speaker systems face challenges in synchronizing audio playback across multiple speakers, determining echo delays for accurate voice recognition, integrating dumb speakers, optimizing playback for specific locations, and automatically identifying present speakers in a room, leading to suboptimal listening experiences.
Innovation Solution
The use of spread spectrum signals and orthogonal spreading codes to calculate playback delays and airtime delays, enabling synchronized audio playback, echo cancellation, and automatic speaker detection and configuration adjustments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If multiple speakers are connected wirelessly to provide surround sound or multi-room audio, then cable installation complexity is reduced, but audio synchronization between speakers deteriorates
Solution Approach 1:
The patent uses an ultrasonic audio signal as an intermediary carrier to transmit timing information between speakers. The ultrasonic signal serves as both the audio content and the synchronization reference, allowing wireless speakers to maintain precise temporal alignment without requiring complex cable connections or separate synchronization protocols.
2Reliability
If manual calibration is performed for each speaker in a multi-speaker system, then audio synchronization can be achieved, but system complexity and setup time increase
Solution Approach 1:
The system performs automatic self-calibration by having each speaker emit and detect ultrasonic signals from other speakers. The speakers independently measure their own playback delays by detecting the timing of received ultrasonic signals, eliminating the need for manual calibration procedures or complex external calibration equipment.
Solution Approach 2:
The patent implements preliminary delay measurement using ultrasonic signals before actual audio playback. By measuring the playback delay in advance through ultrasonic timing, the system pre-configures the necessary delay compensation, ensuring synchronized playback without requiring real-time adjustment or complex runtime calibration procedures.
3Device complexity
If conventional smart speakers are used without ultrasonic signaling, then device simplicity is maintained, but echo delay determination accuracy deteriorates
Solution Approach 1:
The patent uses ultrasonic frequencies (beyond human hearing range) as a distinct 'color' or characteristic of the timing signal. This ultrasonic carrier wave provides a clear, unambiguous temporal reference that is easily distinguishable from other audio content, enabling precise echo delay measurement without complicating the overall device architecture.
Data Source
AI summary
Disclosed herein are system, apparatus, article of manufacture, method and/or computer program product embodiments, and/or combinations and sub-combinations thereof, for synchronizing playback of audiovisual content with a dumb speaker. In some embodiments, a display device transmits a spread spectrum signal to a dumb speaker over a data channel using a spread spectrum code. The display device then receives the spread spectrum signal from the dumb speaker over an audio data channel. The display device despreads the spread spectrum signal based on the spreading code. The display device determines a time of receipt of the spread spectrum signal. The display device calculates an audiovisual output path delay for the dumb speaker based on the time of receipt and a time of transmission. The display device then synchronizes the playback of the audiovisual content at the dumb speaker and a smart speaker based on the audiovisual output path delay.