Headrest Side-Firing Loudspeaker Waveguide for Consistent Audio Zones

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Solution Overview

Problem

Conventional loudspeaker configurations in headrests, whether positioned behind or on the sides, suffer from inefficiencies in sound dispersion and inter-aural performance, leading to undesirable listening experiences due to listener head position dependence and lack of seat-to-seat separation.

Innovation Solution

A side-firing loudspeaker module with a waveguide mounted on the lateral surface of the headrest, oriented to direct sound forward, using a non-converging exit opening and an acoustic lens to optimize audio distribution, ensuring sound is directed towards the listener without disturbing others.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If loudspeakers are positioned behind the listener in the headrest, then sound can be reproduced for music and movie content, but the sound field becomes dependent on listener head position causing undesirable listening experience

Engineering Contradiction:

Improvelistening experience consistencyVSAvoidhead position independence

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent transitions from traditional front-firing or rear-firing speaker configurations to side-firing speakers mounted on the lateral surfaces of the headrest. This dimensional change in speaker orientation allows sound to be directed toward the listener's ears from the sides, creating more consistent audio performance regardless of head position while maintaining compact headrest dimensions.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Volume of moving object

If loudspeakers are mounted to one or more sides of the headrest to address size limitations, then packaging constraints are satisfied, but sound dispersion control becomes inefficient

Engineering Contradiction:

Improveheadrest sizeVSAvoidsound dispersion control

Core Design Contradiction:

Volume of moving objectVSReliability

Solution Approach 1:

The patent introduces waveguides as intermediary components between the side-mounted loudspeaker drivers and the external environment. These waveguides serve as acoustic channels that control and direct sound dispersion from the lateral speaker positions, enabling efficient sound distribution despite the compact side-mounted configuration.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Reliability

If front surface acoustic radiators are used to create sound output, then sound can be projected forward, but the headrest size becomes large

Engineering Contradiction:

Improvesound projection capabilityVSAvoidheadrest size

Core Design Contradiction:

ReliabilityVSVolume of moving object

Solution Approach 1:

The patent relocates the acoustic radiation function from the front surface to the lateral surfaces of the headrest. By mounting speakers on the sides and using waveguides to direct sound forward, the system achieves effective sound projection without requiring a large front surface area, thus reducing overall headrest dimensions.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

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

Enhances individual sound zones for each seat by providing efficient sound dispersion and minimizing sound variations based on listener head position, improving the listening experience by maintaining focused audio delivery.

Implementation Method 1

A first waveguide has an opening in the lateral direction, x, and an exit opening in a forward direction, y. The forward direction, y, is generally perpendicular to the lateral direction, x. The first waveguide is mounted to the first loudspeaker driver so that the opening aligns with a radiating surface of the first loudspeaker driver and the exit opening extends along the first lateral non-contact surface of the headrest exteriorly to the headrest.

Methodology Applied

Scientific EffectAcoustic refraction: Refraction

Implementation Method 2

The first waveguide is mounted to the first loudspeaker driver so that the opening aligns with a radiating surface of the first loudspeaker driver

Methodology Applied

Scientific EffectAcoustic reflection: Reflection

Implementation Method 3

In one or more embodiments, the loudspeaker has an acoustic lens above the loudspeaker driver.

Methodology Applied

Scientific EffectAcoustic lens focusing: Lens

Data Source

PatentUS12495246B2Headrest with side-firing loudspeakers

Publication Date: 2025.12.09 HARMAN INT IND INC

AI summary

At least one loudspeaker module having a loudspeaker driver mounted inside a headrest behind a lateral non-contact surface of the headrest and is oriented so that a central axis of radiation is along a lateral direction, x, of the headrest. A waveguide has an opening in the lateral direction, x, and an exit opening in a forward direction, y. The forward direction, y, is generally perpendicular to the lateral direction, x. The waveguide is mounted to the loudspeaker driver so that the opening aligns with a radiating surface of the loudspeaker driver and the exit opening extends along the lateral non-contact surface of the headrest exteriorly to the headrest. The opening is vertically oriented on the lateral non-contact surface of the headrest so that a central axis of radiation of the waveguide is directed toward the forward direction, y. The loudspeaker has an acoustic lens above the loudspeaker driver.