Upward-Firing Driver Virtual Height Filter for Spatial Audio
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Solution Overview
Problem
Current spatial audio systems, such as Dolby Atmos, require expensive installations and complex setups to replicate three-dimensional audio in home environments, particularly for height cues, as they typically need ceiling-mounted speakers, which are not always feasible or affordable.
Innovation Solution
A speaker system with upward-firing drivers and a virtual height filter circuit, which includes both active and passive components like digital signal processing and grill designs, to simulate overhead sound by reflecting sound off the ceiling, providing a pinna filter response without the need for expensive installations or alterations to the home theater setup.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If ceiling-mounted speakers are used to provide height cues in spatial audio systems, then the audio immersion and three-dimensional sound quality are improved, but the installation cost and complexity increase significantly
Solution Approach 1:
Instead of mounting speakers on the ceiling to project sound downward, this patent inverts the approach by using upward-firing drivers that project sound upward to reflect off the ceiling. This inversion achieves the same virtual height effect while using conventional floor or wall-mounted speaker positions, eliminating the need for ceiling installation
Solution Approach 2:
The patent uses upward-firing drivers to create a virtual copy of the overhead speaker effect. By reflecting sound off the ceiling, the system creates a virtual image of the sound source in the ceiling plane, copying the acoustic effect of true ceiling-mounted speakers without requiring actual ceiling installation
2Reliability
If ceiling-mounted speakers are installed to achieve accurate height sound rendering, then the spatial audio quality is improved, but the installation cost increases
Solution Approach 1:
The patent replaces expensive ceiling-mounted speaker installations with conventional upward-firing drivers that can be installed in standard speaker locations. This substitution uses cheaper, more accessible hardware and installation methods while achieving the same virtual height effect through acoustic reflection principles
Solution Approach 2:
The ceiling acts as an intermediary surface that reflects sound from upward-firing drivers to create virtual overhead audio. This intermediary approach allows the system to achieve ceiling speaker effects without directly mounting speakers on the ceiling, using the existing ceiling surface as a reflective medium
3Adaptability or versatility
If upward-firing drivers are used to simulate overhead sound, then the installation flexibility is improved, but the direct sound component interferes with the reflected sound
Solution Approach 1:
The patent extracts and removes the harmful direct sound component from the audio signal sent to upward-firing drivers. By applying a high-pass filter that attenuates low frequencies (below 400-800 Hz), the system eliminates the direct sound path interference while preserving the reflected sound components that create the virtual height effect
Solution Approach 2:
The patent replaces the need for physical ceiling-mounted speakers with an electrical signal processing solution. By using high-pass filtering and upward-firing drivers, the system substitutes mechanical installation complexity with electrical signal manipulation to achieve the same acoustic result
4Reliability
If a high-pass filter is applied to upward-firing drivers to remove direct sound, then the reflected sound quality is improved, but the filter complexity and component cost increase
Solution Approach 1:
The high-pass filter circuit is integrated into the existing crossover network of the speaker system, serving multiple functions simultaneously. The same filter components that separate frequency bands for different drivers also perform the function of removing direct sound components from upward-firing drivers, eliminating the need for separate filtering hardware
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
Enables fully encompassing three-dimensional audio experiences using simple and cost-effective speaker components, effectively compensating for direct and reflected sound cues to recreate the perception of overhead sound sources without the need for ceiling-mounted speakers.
Implementation Method 1
transmitting sound waves to be reflected off of a surface of a listening environment
Data Source
AI summary
Embodiments are directed to a virtual height filter for use with or in an upward-firing speaker system that reflects sound off a ceiling to a listening location at a distance from a speaker, and that provides height cues to reproduce audio objects that have overhead audio components. A virtual height filter based on a directional hearing model is applied to the upward-firing driver signal to improve the perception of height for audio signals transmitted by the virtual height speaker to provide optimum reproduction of the overhead reflected sound. The virtual height filter is provided by any one or combination of analog or digital filter circuits, or mechanical structures including speaker grill, enclosure, or driver design or configuration.