Microphone Gain Control for Balanced Audio Capture
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Solution Overview
Problem
Portable electronic devices with multimedia capabilities face challenges in balancing audio levels between the operator and subject during recording, as the operator's audio often overpowers the subject due to proximity, especially with omnidirectional microphones.
Innovation Solution
An electronic apparatus with a rear-side and front-side microphone configuration, utilizing an automated balance controller to process signals and adjust gains based on imaging signals, such as zoom control or proximity information, to generate beamformed audio signals that balance the audio levels between the operator and subject.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If omnidirectional microphones are used to capture audio from all directions, then the device can record both the operator and subject, but the operator's audio level will overpower the subject's audio level due to proximity
Solution Approach 1:
The patent segments the audio capture function by implementing separate microphones positioned at the front and rear of the device. The front microphone captures subject audio while the rear microphone captures operator audio, allowing independent processing and gain control for each source to prevent audio level imbalance
Solution Approach 2:
The patent applies local quality by assigning different gain characteristics to different spatial zones. The front microphone path uses one gain setting optimized for distant subject capture, while the rear microphone path uses a different gain setting optimized for close operator capture, with automated balance control adjusting these gains based on recording mode
2Reliability
If the operator speaks at normal volume, then the operator can be clearly recorded, but the subject's audio level becomes too low to be useful
Solution Approach 1:
The patent implements dynamic gain control through automated balance that continuously adjusts the relative gain between front and rear microphone signals based on the selected recording mode. This allows the system to adapt to different operational requirements, switching between operator-optimized and subject-optimized audio balance without manual intervention
Solution Approach 2:
The patent changes the audio gain parameter dynamically based on recording mode. In interview mode, the system applies higher gain to the rear microphone to capture operator speech clearly. In recording mode, the system applies higher gain to the front microphone to capture distant subject audio adequately, thereby maintaining reliable audio levels for both parties under different operational conditions
3Manufacturing precision
If manual volume adjustment is required to balance audio levels, then audio balance can be achieved, but the operation becomes complex and user-dependent
Solution Approach 1:
The patent implements self-service through automated balance control that automatically adjusts the relative gain between front and rear microphone signals based on the selected recording mode. The system independently determines and applies the appropriate gain settings without requiring user intervention, thereby achieving precise audio level balance while maintaining simple operation
Solution Approach 2:
The system uses feedback from the selected recording mode to automatically adjust audio gain parameters. The automated balance controller receives input about the current recording mode (interview or recording) and automatically applies the corresponding gain configuration, creating a closed-loop system that maintains optimal audio balance without manual adjustment
Data Source
Figure 1A
Figure 1B
Figure 2A~2B
AI summary
An electronic apparatus is provided that has a rear-side and a front-side, a first microphone (420) that generates a first signal (421), and a second microphone (430) that generates a second signal (431). An automated balance controller (480) generates a balancing signal (464) based on an imaging signal (485). A processor (450) processes the first and second signals (421, 431) to generate at least one beamformed audio signal (452, 454), where an audio level difference between a front-side gain and a rear-side gain of the beamformed audio signal is controlled during processing based on the balancing signal.