Audio Control Unit Phase Correction via Digital Delay
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Solution Overview
Problem
Existing audio systems with subwoofers and other loudspeakers face challenges in phase matching, leading to frequency-dependent delays and interference in sound reproduction, particularly when combining analogue and digital loudspeaker boxes, which complicates bass management and affects the overall hearing experience.
Innovation Solution
A control unit with a configurable filter and adjustable delays is introduced to linearize phase responses of loudspeakers connected to the subwoofer, allowing flexible integration of both analogue and digital loudspeaker boxes, enabling phase correction and matching of delays to ensure coherent sound reproduction across all frequencies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If phase matching is performed using allpass filtering or delay in the frequency separation range, then phase coherence between subwoofer and loudspeaker boxes is improved, but device complexity and signal processing requirements increase
Solution Approach 1:
The patent changes the fundamental parameter of phase correction from frequency-dependent filtering to time-domain delay adjustment. By measuring the actual time delay between subwoofer and loudspeaker signals and applying a corresponding time delay to the loudspeaker output, the system achieves phase coherence without complex frequency-dependent filtering, thereby reducing signal processing complexity while maintaining reliability
Solution Approach 2:
The patent replaces the traditional analogue allpass filtering mechanism with a digital time-delay system. Instead of using analogue filters that require complex circuitry and tuning, the invention uses digital signal processing to introduce precise time delays, substituting a simpler digital mechanism for a more complex mechanical/analogone
2Reliability
If phase linearization is performed using FIR filters in digitally controlled systems, then phase response is improved, but device complexity and processing power requirements increase
Solution Approach 1:
The patent changes the approach from FIR filtering (which operates in the frequency domain and requires complex coefficient calculations) to simple time-domain delay. This parameter change from frequency-domain processing to time-domain processing dramatically reduces computational requirements while achieving the same phase alignment objective
Solution Approach 2:
The patent extracts only the essential function of phase alignment from the complex FIR filtering process. By identifying that the core requirement is simply time delay compensation rather than full frequency-response shaping, the invention removes unnecessary processing complexity and retains only the critical delay function
3Adaptability or versatility
If analogue loudspeaker boxes with inherent phase nonlinearity are integrated into a multiway system, then system compatibility is improved, but phase coherence and sound quality deteriorate
Solution Approach 1:
The patent introduces a digital delay element as an intermediary between the analogue loudspeaker box and the subwoofer. This intermediary component compensates for the phase nonlinearity of the analogue box by introducing a corrective time delay, thereby maintaining phase coherence while preserving system compatibility with existing analogue equipment
Solution Approach 2:
The patent applies preliminary phase correction by measuring and compensating for the inherent phase nonlinearity of analogue loudspeaker boxes before the signals are combined in the multiway system. This preliminary anti-action prevents phase coherence problems from developing in the first place, allowing seamless integration of analogue equipment
Data Source
AI summary
A control unit for an audio system including a subwoofer and at least one further loudspeaker. Type information is recorded via the at least one connected loudspeaker, and a configurable filter for the at least one connected loudspeaker is configured by means of appurtenant configuration information from a memory. The configurable filter is configured so that a base phase management is provided for the transition frequency range between the subwoofer and the at least one connected loudspeaker so that the phase of the sound signals of the subwoofer is matched to the phase of the sound signals of the at least one connected loudspeaker.