Small-Speaker Audio Processing for Higher Perceived Loudness
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Solution Overview
Problem
Portable media devices with small speakers face challenges in producing sufficient volume due to physical size restrictions, leading to low output levels and distortion, especially in noisy environments, and existing solutions compromise portability by adding bulk or extra devices.
Innovation Solution
A system comprising a frequency suppressor, loudness adjuster, and distortion control module that filters out low and high frequencies, calculates and amplifies the audio signal based on human hearing models, and induces partial harmonic distortion to increase perceived loudness without increasing distortion or bulk.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If the amplitude of the audio signal is increased to compensate for low speaker output, then the perceived loudness improves, but distortion is introduced and battery power consumption increases
Solution Approach 1:
The patent changes the frequency distribution parameters of the audio signal by suppressing specific frequency ranges. This allows the overall amplitude to be increased for perceived loudness while maintaining lower actual energy levels, avoiding distortion and excessive power consumption. The frequency suppression modifies the spectral parameters to match speaker capabilities.
Solution Approach 2:
The patent introduces an intermediary processing system between the audio source and speaker that mediates the signal characteristics. By processing the audio signal through frequency suppression and redistribution, the system creates an intermediate signal that the small speaker can reproduce accurately at higher perceived volumes without distortion.
2Illumination intensity
If external speakers are added to increase output levels, then the audio quality improves, but the portability of the device is compromised
Solution Approach 1:
The patent replaces the mechanical solution of adding external speakers with an electronic/digital signal processing solution. By using frequency suppression algorithms and signal manipulation, the system achieves higher effective output from the existing small speaker without adding any physical hardware, maintaining portability while improving audio quality.
3Object-affected harmful factors
If the amplitude is increased to overcome background noise, then the signal becomes audible in noisy environments, but more battery power is consumed
Solution Approach 1:
The patent changes the energy distribution parameters across the frequency spectrum by suppressing certain frequencies and emphasizing others. This allows the audio signal to achieve better audibility in noisy environments through strategic frequency management rather than brute-force amplitude increases, thereby reducing overall power consumption while maintaining intelligibility.
Data Source
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.