Volume-Dependent Loudspeaker Equalization for Frequency Drop-Offs
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Solution Overview
Problem
Loudspeaker systems often exhibit low frequency and high frequency drop-offs in their frequency transfer function, leading to deficiencies in sound reproduction, particularly at low and high frequencies, which existing technologies have not adequately addressed.
Innovation Solution
A loudspeaker system comprising an input unit, an equalization unit that applies specific equalization functions based on volume settings to modify audio signals, and a loudspeaker unit, which converts these signals into acoustic output, thereby compensating for frequency deficiencies by applying frequency-dependent attenuation and using filters to adjust the audio signal according to predefined equalization functions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a fixed dedicated extra gain is applied at low frequencies to compensate for frequency drop-off, then low frequency reproduction is improved, but the system lacks adaptability to different volume levels and signal conditions
Solution Approach 1:
The patent implements dynamic equalization where the equalization function automatically adjusts based on the current volume level setting. Multiple equalization functions are stored in memory, each optimized for specific volume ranges, and the system dynamically selects the appropriate function based on the current operating point. This resolves the contradiction by making the equalization adaptive rather than fixed, maintaining reliable low frequency reproduction across all volume levels while adapting to different operating conditions.
Solution Approach 2:
The system changes the equalization parameters (gain values, frequency characteristics) based on the volume level parameter. By storing multiple equalization functions with different parameter sets in memory and selecting the appropriate one based on the current volume setting, the system maintains optimal frequency compensation across varying operating conditions. This allows the same hardware to deliver reliable low frequency reproduction whether the volume is low or high.
2Adaptability or versatility
If multiple equalization functions are stored in memory and selected based on volume level, then adaptability to different volume levels is improved, but device complexity increases
Solution Approach 1:
The equalization system is segmented into multiple discrete equalization functions, each optimized for specific volume level ranges. Instead of implementing a single complex continuous adjustment system, the patent divides the equalization task into multiple simpler, pre-computed functions stored in memory. The controller simply selects the appropriate segment (equalization function) based on the current volume level, reducing the complexity of real-time processing while maintaining high adaptability.
3Reliability
If equalization is applied to compensate for frequency drop-off, then sound reproduction quality is improved, but power consumption increases
Solution Approach 1:
Multiple equalization functions are pre-computed and stored in memory before operation. Instead of calculating equalization parameters in real-time based on volume changes, the system performs the computationally intensive work beforehand and stores the results. During operation, the equalization unit only needs to retrieve and apply the pre-computed function corresponding to the current volume level, significantly reducing real-time processing power consumption while maintaining high sound reproduction quality.
Data Source
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AI summary
The application relates to a loudspeaker system comprising a) an input unit providing an electric input audio signal; b) an equalization unit for modifying said electric input audio signal or a processed version thereof in dependence on frequency and to provide an equalized electric audio signal according to a predefined equalization function, c) a loudspeaker unit for converting said equalized electric audio signal or a processed version thereof to an acoustic output sound signal, and d) a user interface for modifying a volume level of said output sound signal in a multitude (N) of steps Vo, V1, ..., VN. The application further relates to a method communication device comprising the loudspeaker system and to its use. The object of the present application is to provide an improve loudspeaker system. The problem is solved in that the equalization unit - e.g. in a particular mode of operation of the loudspeaker system - is configured to apply a specific equalization function EQ0, EQ1, ..., EQN to the electric input audio signal in each of said multitude of steps Vo, V1, ..., VN of the volume level. This has the advantage of allowing an equalization to be adapted to a specific user selected volume level of the loudspeaker unit. The invention may e.g. be used for the handsfree telephone systems, mobile telephones, teleconferencing systems (e.g. speakerphones), public address systems, karaoke systems, classroom amplification systems, etc.