Acoustic Reflector for Height Channel Speaker Thickness Constraints
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Solution Overview
Problem
Conventional height channel speakers face challenges in achieving effective upward firing due to thickness constraints, leading to destructive interference and reduced acoustic output, especially when integrated into devices like flat-panel displays where the distance between the transducer and the recessed wall is minimized, resulting in perception of sound from the wall rather than the ceiling.
Innovation Solution
The integration of an acoustic reflector that mounts on an inclined plane with the height speaker transducer, focusing acoustic energy upwards by creating a virtual image of the sound source outside the speaker enclosure, overcoming thickness limitations and enhancing the upward firing effect by reflecting sound off the ceiling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the distance between the transducer and the recessed wall structure is reduced to meet thickness constraints, then the device can be integrated into flat-panel displays and portable devices, but acoustic energy is reflected off the recessed wall structure instead of the ceiling, causing destructive interference and minimizing height channel reproduction
Solution Approach 1:
An acoustic reflector is introduced as an intermediary component between the transducer and the recessed wall structure. This reflector redirects acoustic energy that would otherwise reflect off the wall structure back toward the ceiling, preventing destructive interference while maintaining the thin form factor required for integration into flat-panel displays and portable devices
Solution Approach 2:
The acoustic reflector creates a virtual image of the transducer positioned above the ceiling plane. This virtual copy allows the system to maintain the appearance of a thin speaker while effectively projecting sound upward to create height channel effects, as the reflected sound appears to originate from a source above the listener
2Volume of moving object
If a narrow (thin) transducer is used to meet thickness limitations, then the speaker can be integrated into space-constrained devices, but the far field pressure radiated is reduced and the dispersion pattern becomes narrower compared to conventional height speakers
Solution Approach 1:
The acoustic reflector employs a curved surface geometry that focuses and redirects acoustic energy from the thin transducer. This curvature allows the reflector to concentrate sound waves and expand the dispersion pattern, compensating for the limited radiating surface area of the narrow transducer while maintaining the thin form factor
Solution Approach 2:
The acoustic reflector extends the effective radiating surface into the vertical dimension by creating a virtual image above the ceiling. This dimensional extension allows a thin transducer to achieve the acoustic output of a larger transducer, as the reflected sound waves propagate as if originating from a larger effective aperture
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 solution effectively enhances the perception of audio height cues by focusing acoustic energy towards the ceiling, improving the acoustic output and dispersion pattern of height channel speakers, even in constrained spaces, by creating a virtual sound source outside the speaker enclosure.
Implementation Method 1
The acoustic reflector is used to reflect, shape, and focus acoustic energy originating from the height speaker transducer upwards to the ceiling
Implementation Method 2
The acoustic reflector reflects and focuses a majority of incident sound radiation towards the ceiling in a forward-upward-inclined direction
Implementation Method 3
The acoustic reflector effectively helps to overcome the constrained thickness of the transducer by creating a virtual image of the real sound source outside of the height speaker enclosure
Data Source
Figure 1A~1B
Figure 1C~1D
Figure 2A
AI summary
A height channel speaker with an integrated acoustic reflector to reflect sound off of a ceiling down to a listener. The acoustic reflector compensates for thin transducers by creating a virtual image of the real sound source outside the speaker enclosure. The focal point of the acoustic reflector is controlled by modifying the curvature of the reflector surface. The transducer is mounted on an inclined plane to radiate sound in a rear-upward inclined direction. The acoustic reflector is mounted on the same inclined plane so that the radiant axis of the transducer is directly incident on the acoustic reflector surface. The sound is projected towards the ceiling in a forward, upward-inclined direction to reflect off the ceiling and down to the listener. The speaker can be acoustically occluded from the listener by a panel to which the speaker is attached.