Sound Field Reflection Adjustment for Room-Adaptive Audio
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Solution Overview
Problem
Existing sound field effect technologies struggle to accurately adjust the sound field effect in response to varying reproduction environments, often resulting in the effect being too strong or too weak compared to the intended experience.
Innovation Solution
A sound field controller that includes an input section, sound field generation section, acquisition section, identification section, adjustment section, and output section, which emits a test sound to measure sound pressure levels, identifies the maximum reflected sound, and adjusts the effect sound signal based on the ratio of direct to reflected sound pressure levels to tailor the sound field effect to the specific reproduction environment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a predetermined ideal reproduction environment is used as reference for sound field effect, then the sound field effect can be generated based on a specific virtual sound source distribution, but the effect may be too strong or too weak when the actual reproduction environment differs from the reference environment
Solution Approach 1:
The system emits a test sound and measures the actual reflected sound in the reproduction environment using a microphone. The measurement result is fed back to the adjustment section, which compares the measured reflected sound level with the reference reflected sound level from the ideal environment. Based on this feedback, the effect sound signal is automatically adjusted to match the actual environment, resolving the contradiction between adaptability and accuracy.
Solution Approach 2:
The system changes the parameters of the effect sound signal (specifically the level of reflected sound components) based on the measured acoustic characteristics of the actual reproduction environment. By adjusting the ratio of direct sound to reflected sound in the effect signal to match the measured environment, the system adapts the sound field effect to different reproduction environments while maintaining accuracy.
2Measurement precision
If the sound field effect is adjusted based on measured reflected sound levels, then the effect can be optimized for the specific environment, but additional measurement and processing steps are required
Solution Approach 1:
The system uses the existing reproduction environment itself as the measurement tool by emitting a test sound and capturing its reflection with a microphone placed in the listener's position. This self-service approach eliminates the need for external complex measurement equipment or manual environment characterization, achieving accurate adaptation with minimal additional complexity.
Solution Approach 2:
The system performs preliminary measurement of the reproduction environment by emitting a test sound before reproducing the actual audio content. This preliminary action characterizes the acoustic properties (direct sound level, reflected sound level, time delay) of the environment in advance, allowing the effect sound signal to be pre-adjusted to match the environment, thereby simplifying the overall process.
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 precise adjustment of the sound field effect to match the listener's environment, ensuring an optimal audio experience by accounting for the unique acoustic characteristics of the reproduction space.
Implementation Method 1
an acquisition section which acquires a measurement signal indicating sound pressure levels of a direct sound and a reflected sound which are collected when a test sound is emitted in a reproduction environment
Data Source
AI summary
A sound field controller includes: a sound field generation section which generates an effect sound signal for giving a sound field effect sound to an audio signal; an acquisition section which acquires a measurement signal indicating sound pressure levels of a direct sound and a reflected sound which are collected when a test sound is emitted in a reproduction environment; an identification section which identifies a maximum reflected sound whose sound pressure level is the maximum in a given time period after a collecting timing of the direct sound from the measurement signal; an adjustment section which adjusts the effect sound signal based on a ratio of the sound pressure level of the direct sound to the sound pressure level of the maximum reflected sound; and an output section which outputs the audio signal input to the input section and the effect sound signal adjusted by the adjustment section.