Audio Apparatus Plane Wave Sound Field Elevation
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Solution Overview
Problem
Existing audio technologies that generate virtual audio with a sense of elevation using multiple speakers on the same plane have a limited 'sweet spot' performance, restricting the ability for users to experience this audio from various positions, as they are optimized for a single central point.
Innovation Solution
An audio apparatus and method that apply a combination of gain values and delay values to virtual audio signals to create a plane wave sound field, allowing these signals to be output through multiple speakers, thereby enabling a wider range of listening positions by using a head-related transfer filter (HRTF) and panning gain values to simulate audio at different heights.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If audio is optimized and rendered at one central point using conventional virtual audio generation, then the audio quality at the sweet spot is improved, but the listening area is restricted and users cannot experience virtual audio giving a sense of elevation from various positions
Solution Approach 1:
The patent applies HRTF (Head-Related Transfer Function) filtering to process audio signals in the vertical dimension, enabling speakers positioned on a horizontal plane to generate virtual audio sources that perceive as being at different heights. This dimensional transformation allows the system to create elevation perception without physically positioning speakers at different heights, thereby expanding the listening experience while maintaining sweet spot quality
Solution Approach 2:
The patent modifies audio signal parameters by applying HRTF filters with specific frequency responses and time delays that simulate sound propagation from elevated positions. By changing the spectral and temporal characteristics of the audio signals through filtering, the system creates the perception of height while maintaining compatibility with horizontal speaker arrangements, thus expanding the effective listening area
2Device complexity
If multiple speakers are positioned on the same horizontal plane to generate virtual audio with elevation, then the device complexity is reduced compared to using speakers at different heights, but the sweet spot becomes narrow and performance is limited to one point
Solution Approach 1:
The patent introduces HRTF filtering as an intermediary processing stage between the audio source and the speakers. This intermediary applies frequency-dependent gain adjustments and time delays to simulate the acoustic effects of sound traveling from elevated positions, enabling the horizontal speaker arrangement to produce vertical localization cues that would normally require three-dimensional speaker placement
Solution Approach 2:
The patent replaces the mechanical solution of positioning speakers at different physical heights with an electronic signal processing approach. Instead of physically arranging speakers in three-dimensional space, the system uses HRTF-based digital filtering to synthesize the acoustic characteristics of elevated sound sources, thereby simplifying the mechanical configuration while maintaining or improving localization accuracy
3Device complexity
If conventional audio signal processing is used without HRTF filtering, then the system simplicity is maintained, but the ability to generate a sense of elevation is lost
Solution Approach 1:
The patent applies HRTF filtering in advance to the audio signals before they are sent to the speakers. This preliminary processing pre-computes the frequency-dependent gain adjustments and time delays needed to simulate sound propagation from elevated positions, so that when the signals are played through horizontal speakers, the elevation effect is already embedded in the signal characteristics
Data Source
AI summary
An audio apparatus and an audio providing method thereof are provided. The audio providing method includes receiving an audio signal including a plurality of channels, applying an audio signal having a channel, from among the plurality of channels, giving a sense of elevation to a filter to generate a plurality of virtual audio signals to be respectively output to a plurality of speakers, applying a combination gain value and a delay value to the plurality of virtual audio signals so that the plurality of virtual audio signals respectively output through the plurality of speakers form a sound field having a plane wave, and respectively outputting the plurality of virtual audio signals, to which the combination gain value and the delay value are applied, through the plurality of speakers. The filter processes the audio signal to have a sense of elevation.