Speaker Loudness Processing with Frequency Suppression and Harmonic Distortion
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Solution Overview
Problem
Portable media devices with small speakers face challenges in producing sufficient volume due to physical size constraints, leading to low output levels and distortion, especially in noisy environments, and existing solutions compromise portability by adding bulk or multiple devices.
Innovation Solution
A system comprising a frequency suppressor, loudness adjuster, and distortion control module that filters out low and high frequencies, calculates and applies gains to increase perceived loudness, and induces partial harmonic distortion to enhance audio signal energy, effectively increasing loudness without increasing volume or bulk.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the size of the loudspeaker is increased to improve output level, then the loudness is improved, but the portability of the device is compromised
Solution Approach 1:
The patent applies parameter changes by modifying the audio signal's frequency content and amplitude characteristics through digital processing. The frequency suppressor removes specific frequency bands, and the loudness adjuster dynamically modifies signal parameters to increase perceived loudness without requiring physical speaker enlargement, thus maintaining portability while improving output level.
Solution Approach 2:
The patent replaces the mechanical approach of increasing speaker size with a digital signal processing system. Instead of using larger mechanical components to generate more sound output, the system uses electronic frequency suppression and loudness adjustment algorithms to achieve the same effect, substituting mechanical solutions with electronic/software-based solutions.
2Power
If the amplitude of the audio signal is increased to improve loudness, then the output level is improved, but distortion is introduced
Solution Approach 1:
The patent applies preliminary action by performing frequency suppression before amplitude adjustment. The frequency suppressor pre-processes the audio signal to remove problematic frequency components that would cause distortion when amplified, allowing subsequent loudness adjustment to occur without introducing the same level of distortion that would result from directly amplifying the full-frequency signal.
3Power
If additional hardware is added to combat low output levels, then the loudness is improved, but the portability is compromised
Solution Approach 1:
The patent applies universality by integrating multiple functions into a single device. The portable media device incorporates both the frequency suppressor and loudness adjuster functions within its existing architecture, eliminating the need for separate external speakers or additional gadgets. This multi-functional approach maintains portability while improving output level.
Data Source
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AI summary
A system can be provided for increasing loudness of an audio signal to present a perceived loudness to a listener that is greater than a loudness provided natively by a loudspeaker. The system can include one or more of the following: a frequency suppressor, a loudness adjuster, an equalizer, and a distortion control module. The frequency suppressor can increase headroom in the audio signal by filtering out low and/or high frequencies. The loudness adjuster can calculate a loudness of the audio signal and apply a gain to the audio signal to increase the loudness. The equalizer can further increase headroom by attenuating portions of a passband of the loudspeaker's frequency response. The distortion control module can induce partial harmonic distortion in the audio signal to further increase loudness.