Line-In Audio Detection for Automatic Source Switching

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Solution Overview

Problem

Existing audio playback systems require manual switching between sources when connecting audio devices via line-in connections, lacking automatic detection and switching capabilities.

Innovation Solution

A playback device with network interface and processor that automatically detects line-in signals, switches sources, and adjusts volume levels to enhance dynamic range, allowing seamless audio streaming from multiple sources.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If manual switching between sources is used, then device complexity is reduced, but ease of operation deteriorates

Engineering Contradiction:
Improveease of operationVSAvoiddevice complexity
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The system automatically detects line-in signals and performs source switching without requiring user intervention. The playback device monitors the line-in connector and autonomously determines when to switch sources based on detected audio signals, eliminating the need for manual source selection while maintaining system simplicity

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The system changes operational parameters by adjusting volume levels dynamically when switching between sources. When a line-in signal is detected and source switching occurs, the system modifies the volume parameter to enhance dynamic range, allowing seamless adaptation to different audio sources without manual intervention

Inventive Principle:
Principle #35Parameter changes

2Productivity

If automatic source switching is implemented, then productivity is improved, but device complexity increases

Engineering Contradiction:
ImproveproductivityVSAvoiddevice complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The system implements feedback by continuously monitoring the line-in connector for audio signals. The playback device detects the presence of line-in signals and uses this feedback information to automatically trigger source switching, creating a closed-loop system that responds to real-time conditions without requiring complex user interfaces

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system prepares for source switching by continuously monitoring the line-in connector in advance. When an audio signal is detected on the line-in connection, the system has already been prepared to switch sources, enabling rapid and seamless transitions without interrupting the user experience

Inventive Principle:
Principle #10Preliminary action

3Reliability

If volume adjustment for dynamic range enhancement is applied, then audio quality is improved, but device complexity increases

Engineering Contradiction:
Improveaudio qualityVSAvoiddevice complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The system changes the volume parameter dynamically when switching to line-in sources. By adjusting volume levels to enhance dynamic range, the system optimizes audio quality for different source types without requiring complex audio processing algorithms, maintaining simplicity while improving playback performance

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP4379718B1Smart line-in processing for audio volume
Publication Date: 2025.07.02 SONOS INC
  • EP4379718B1 patent drawingFigure 1
  • EP4379718B1 patent drawingFigure 2A
  • EP4379718B1 patent drawingFigure 2B

AI summary

A method for a playback device. The playback device is configured to receive a first audio signal from a first audio source and to receive a second audio signal from a second audio source. The method comprises: playing back the second audio signal from the second audio source at a first volume level; while playing back the second audio signal, determining that the first audio signal is present from the first audio source; and in response to determining that the first audio signal is present, causing the first playback device to playback the first audio signal at a second volume level.