Smartphone Sound Field Control Using Virtual Reference Timing
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Solution Overview
Problem
Conventional sound field control systems using smartphones for sound emission commands face challenges in accurately measuring the time between sound emission and pickup due to communication lag, preventing precise sound field control.
Innovation Solution
A sound field control system that includes a sound emission unit, a sound pickup unit, and an analysis unit, which calculates the time difference between sound emission and pickup timings using a test signal sequence, allowing for accurate delay processing of voice signals to each speaker, even when the time between sound emission and pickup is unknown.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a smartphone is used for issuing sound emission commands and performing sound pickup, then the cost of the acoustic device can be decreased and wire routing can be eliminated, but accurate sound field control cannot be performed due to unknown time between sound emission command and sound emission
Solution Approach 1:
The patent creates a virtual reference signal that copies the expected sound emission timing information and transmits it to the smartphone. This virtual reference signal serves as a timestamp marker that allows the smartphone to accurately determine when sound emission should occur, compensating for the lack of direct timing control from the acoustic device.
Solution Approach 2:
The patent implements a feedback mechanism where the smartphone receives the virtual reference signal indicating expected sound emission timing, measures the actual time difference between expected and actual sound pickup, and uses this feedback to calculate accurate time differences for sound field control despite communication lag.
2Ease of operation
If the conventional sound field control algorithm is used with smartphone, then the system can operate without attached microphone, but communication lag causes inaccurate time measurement between sound emission command and sound emission
Solution Approach 1:
The patent introduces a virtual reference signal as an intermediary that carries timing information from the acoustic device to the smartphone. This intermediary element bridges the communication gap and provides the smartphone with accurate reference timing data without requiring direct control over the sound emission process.
Solution Approach 2:
The patent performs preliminary transmission of the virtual reference signal containing expected sound emission timing information before the actual sound emission occurs. This allows the smartphone to have advance knowledge of when sound should be emitted, enabling accurate timing measurement even with communication lag.
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
Enables accurate sound field control using a smartphone without the need for a microphone attachment, reducing costs and eliminating the burden of wire routing, while maintaining precision despite potential communication instability.
Implementation Method 1
a sound emission unit which causes a plurality of speakers to emit a test sound
Implementation Method 2
a sound pickup unit which picks up the test sound using a microphone
Data Source
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AI summary
A sound field control system SY according to the present invention is provided with: a sound emission unit 210 which causes a plurality of speakers to emit a test sound; a sound pickup unit 130 which picks up the test sound using a microphone; an analysis unit 150 which compares information indicating a sound emission timing of a test signal sequence for causing the speakers to successively emit the test sound at a prescribed timing with a sound pickup timing of each test sound that has been picked up, and which calculates a time difference between the sound emission timing of each test sound and the sound pickup timing; and a signal processing unit 230 which performs, based on the calculated time difference between the sound emission timing of each test sound and the sound pickup timing, a delay process for a voice signal supplied to each speaker.