Shoulder Speaker Equalization for Higher SPL and Battery Life
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Solution Overview
Problem
Acoustic devices designed to be worn draped over the shoulders typically do not produce sound at sufficient amplitude when used as portable speakers, and increasing volume to address this issue adversely affects battery life.
Innovation Solution
The acoustic device employs two equalization modes: a personal listening mode for when worn and an out-loud listening mode for when placed on a surface, with the out-loud mode de-emphasizing frequencies below 100-200 Hz and boosting those above, using dual acoustic drivers and an audio signal control system to achieve increased sound pressure levels with minimal power increase.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If the volume is turned up to increase sound amplitude, then the sound pressure level is improved, but battery life is adversely affected
Solution Approach 1:
The patent applies different equalization parameter settings based on usage mode. In personal listening mode, full frequency range is maintained for quality audio experience. In out-loud listening mode, the equalization parameters are changed to de-emphasize low frequencies (below 100-200 Hz) and boost mid-high frequencies, which are more efficiently radiated by the acoustic drivers in free-air placement. This parameter adaptation allows the device to achieve sufficient sound pressure level at a distance while consuming less power than would be required to maintain full bass response.
2Illumination intensity
If the device is used as a portable speaker on a surface, then sound amplitude is insufficient, but increasing volume consumes excessive power
Solution Approach 1:
The audio signal control system automatically or manually switches between equalization modes based on the listening context. When placed on a surface for out-loud listening, the system applies the second equalization mode that de-emphasizes frequencies below 100-200 Hz and boosts frequencies above this threshold. This allows the acoustic drivers to operate more efficiently in the mid-high frequency range where they can project sound effectively at a distance without requiring excessive power, thus achieving sufficient sound amplitude while maintaining reasonable power consumption.
3Reliability
If low frequency content is maintained in out-loud mode, then audio quality is preserved, but power consumption increases significantly
Solution Approach 1:
The patent applies different quality characteristics to different frequency ranges based on the listening mode. In out-loud listening mode, the equalization selectively maintains higher quality in the mid-high frequency range (above 100-200 Hz) where the acoustic drivers can efficiently radiate sound in free air, while reducing the energy allocation to low frequencies (below 100-200 Hz) which are less efficiently radiated and consume disproportionate power. This local quality adaptation ensures acceptable audio quality for the intended use while significantly reducing power consumption compared to maintaining full low-frequency content.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration allows the device to produce up to 10 dB louder sound in out-loud mode with only twice the power usage of the personal mode, significantly extending battery life by reducing low-frequency energy consumption.
Implementation Method 1
a first acoustic driver carried by the first leg portion, a second acoustic driver carried by the second leg portion, and an audio signal control system that directs audio signals to each of the first and second drivers, where the drivers transduce the audio signals to output sounds
Implementation Method 2
The housing may comprise a first acoustic waveguide with a first fundamental frequency and that is acoustically coupled to the first acoustic driver, and a second acoustic waveguide with a second fundamental frequency and that is acoustically coupled to the second acoustic driver
Data Source
AI summary
An acoustic device with a housing with a central portion and first and second leg portions that depend from the central portion, a first acoustic driver carried by the first leg portion, a second acoustic driver carried by the second leg portion, and an audio signal control system that directs audio signals to each of the first and second drivers, where the drivers transduce the audio signals to output sounds. The audio signal control system is arranged to apply first and second equalization modes to the audio signals in a first and second listening mode, respectively. The second equalization de-emphasizes frequencies below a first threshold frequency and boosts frequencies above the first threshold frequency.