Reflective Loudspeaker Imaging for Accurate Sound Localization
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Solution Overview
Problem
Existing ceiling-mounted loudspeaker systems for home theaters and cinemas face aesthetic and sonic challenges, as they are visually obtrusive and fail to accurately position sound, especially at lower frequencies, leading to poor electro-acoustical performance and spatial positioning errors.
Innovation Solution
Employing directional transducers that beam sound waves to reflective surfaces, using low and mid-frequency transducers to enhance clarity and simulate sound origin from these surfaces, while controlling dispersion and path lengths to correct localization errors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If ceiling-mounted loudspeakers are used to achieve aesthetic advantages and hide speakers from view, then visual appearance is improved, but sound localization accuracy deteriorates due to displacement between speaker location and picture location
Solution Approach 1:
The patent introduces a reflective surface (mirror or glossy surface) as an intermediary between the ceiling-mounted speaker and the listener. The speaker is positioned above the listener, and sound is reflected off the intermediate surface to create the perception that sound originates from the screen location, resolving the localization error while maintaining aesthetic benefits
Solution Approach 2:
The patent utilizes the vertical dimension by mounting speakers on the ceiling rather than on walls or stands. This dimensional change allows speakers to be hidden from view while using acoustic reflection to project sound images to the correct horizontal positions on the screen
2Shape
If traditional ceiling-mounted loudspeakers are used, then aesthetic advantages are achieved, but sound clarity deteriorates due to energizing the reverberant field of upper portions of the room
Solution Approach 1:
By introducing a reflective surface as an intermediary, the system creates a direct acoustic path from the speaker to the listener via reflection, bypassing the reverberant field of the upper room portions. This maintains sound clarity while preserving the aesthetic advantage of concealed speakers
Solution Approach 2:
The patent replaces the traditional direct-radiation acoustic path with a reflected acoustic path. Instead of sound traveling directly from ceiling speakers to listeners through the reverberant field, the sound is substituted to travel via reflection off a controlled surface, improving clarity
3Measurement precision
If directional transducers beam sound waves to reflective surfaces to achieve accurate sound localization, then sound localization accuracy is improved, but device complexity increases due to controlled dispersion requirements
Solution Approach 1:
The patent applies controlled dispersion only to the extent necessary for mid and high frequencies where directional beaming is effective. Low frequencies are handled separately by omnidirectional transducers, avoiding the complexity of controlling dispersion across the entire frequency spectrum
4Measurement precision
If directional beaming is used for mid and high frequencies to achieve accurate localization, then sound localization is improved, but low frequency reproduction deteriorates due to unreasonably large transducer size requirements
Solution Approach 1:
The patent segments the frequency spectrum into low frequencies and mid/high frequencies. Different transducer types are assigned to different frequency ranges: omnidirectional transducers handle low frequencies where directional beaming is impractical, while directional transducers handle mid and high frequencies where localization accuracy is critical
Solution Approach 2:
The patent creates a multi-functional transducer system where omnidirectional transducers provide low frequency reproduction and directional transducers provide mid and high frequency localization. The system as a whole handles the complete frequency spectrum with each component optimized for its specific frequency range
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
The system provides aesthetically pleasing sound localization by simulating sound origin from intended surfaces, enhancing clarity and reducing localization errors across the frequency spectrum.
Implementation Method 1
sound is reflected off the reflecting surfaces in a specular fashion
Data Source
AI summary
An electro-acoustic system including at least one directional transducer unit configured to generate a controlled sound radiation beam aimed at a reflection surface to bounce the sound off said reflection surface at a specular bounce point and thus create for a listener the perception that the sound originates from a sound impression area of said reflection surface.