Speaker Frequency Correction for Low-Volume Audibility
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Solution Overview
Problem
Existing techniques fail to sufficiently improve sound quality in low and high frequency ranges for small speakers, leading to difficulty in hearing sounds at low volumes due to insufficient sound pressure.
Innovation Solution
An information processing apparatus and method that corrects the frequency characteristic of a speaker's output sound by adjusting the attenuation amount based on volume level, using volume lower limit values determined by sound pressure level differences between maximum and minimum audible volumes at specific frequencies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If known loudness correction techniques are used, then middle frequency sound quality is improved, but low and high frequency sound pressure remains insufficient
Solution Approach 1:
The patent applies different correction strategies to different frequency ranges. Specifically, it applies loudness correction based on equal-loudness contours to the middle frequency range while applying separate sound pressure enhancement processing to the low and high frequency ranges. This localized approach allows each frequency band to be optimized independently according to its specific characteristics and requirements.
2Power
If volume level is reduced, then output sound level is lowered, but sound pressure in low and high frequency ranges becomes insufficient
Solution Approach 1:
The patent implements dynamic frequency characteristic correction that adapts to different volume levels. The correction amount and processing parameters are adjusted based on the current volume level setting, allowing the system to maintain optimal sound quality and sufficient sound pressure in low and high frequency ranges across various output levels. This dynamic adjustment ensures that even at low volumes, the enhanced frequencies remain audible.
3Volume of moving object
If small speaker is used in mobile terminal, then device size is reduced, but frequency characteristic shows higher middle range sound pressure and insufficient low and high range sound pressure
Solution Approach 1:
The patent changes the acoustic parameters of the small speaker's output by applying digital signal processing. It modifies the frequency response characteristics through equal-loudness contour-based correction and sound pressure enhancement, transforming the inherently unbalanced frequency distribution of small speakers into a more balanced output that compensates for the physical limitations of compact speaker design.
Data Source
AI summary
An information processing apparatus comprises a volume level information acquirer that acquires volume level information regarding a setting of a volume level by a user; and a signal processor that corrects a frequency characteristic of an output sound from a speaker and thus causes an attenuation amount from a maximum volume of the output sound from the speaker at a predetermined frequency to be within a range indicated by a volume lower limit value relative to the maximum volume at the predetermined frequency, according to the volume level indicated by the volume level information, wherein the volume lower limit value is determined according to a first sound pressure level difference at a reference frequency between the maximum volume of the speaker and a minimum audible volume that a human is capable of hearing and a second sound pressure level difference at different frequency different from the reference frequency between the maximum volume and the minimum audible volume, with a difference at the reference frequency between the maximum volume and a minimum volume that is settable for the output sound from the speaker as a reference.