Dipole Speaker Null Plane Microphone Placement
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Voice-controlled speakers face interference and poor voice recognition due to sound emissions above 90 dB, requiring users to speak louder or move closer, as conventional speakers struggle to differentiate human voices from loud sound waves.
Innovation Solution
A dipole speaker design with microphones positioned along a null sound plane, where sound pressure is minimized, combined with electro-dynamic and electrostatic transducers arranged to cover a wide audio frequency range, allowing for improved voice activation even at high sound levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If conventional speakers are used to produce loud sound, then sound pressure increases above 90 dB, but voice recognition accuracy deteriorates due to interference between sound emissions and human voices
Solution Approach 1:
The patent positions microphones in a spatial dimension where sound pressure is naturally minimized - specifically at the null points of a dipole speaker's sound field. By moving the microphone location to these null points (along the axis perpendicular to the speaker face), the system achieves voice recognition capability while the speaker operates at high sound pressure levels for audio output.
Solution Approach 2:
The patent uses the dipole speaker's own sound field structure as an intermediary to protect the microphones from sound interference. The null sound planes created by the dipole configuration serve as a natural acoustic barrier, allowing microphones to remain physically close to the speaker while being acoustically isolated from its emissions.
2Volume of moving object
If microphones are positioned close to the speaker for compact design, then device size decreases, but voice recognition deteriorates due to sound interference
Solution Approach 1:
Instead of placing microphones in front of or behind the speaker where sound pressure is high, the patent positions them along the lateral axis at null points. This dimensional repositioning allows compact integration while maintaining acoustic isolation, as the microphones occupy a different spatial zone where the speaker's sound emissions are minimal.
Solution Approach 2:
The patent converts the dipole speaker's inherent sound cancellation characteristic (which creates null planes) into a beneficial feature for microphone protection. The same acoustic physics that creates the dipole radiation pattern also creates protected zones where microphones can operate without interference from the speaker's own emissions.
3Measurement precision
If dipole speaker configuration is used with microphones at null sound plane, then voice recognition improves, but device complexity increases due to specific transducer arrangement
Solution Approach 1:
The dipole speaker configuration serves dual functions: it provides the primary audio output and simultaneously creates protected acoustic zones for the microphones. The same transducer arrangement that generates the sound field also generates the null planes, eliminating the need for separate protective structures or complex acoustic isolation mechanisms.
Solution Approach 2:
The patent merges the audio reproduction function and voice recognition protection function into a single integrated system. The dipole transducer arrangement is not just for sound output but also serves as the acoustic shield for the microphones, combining what could be separate systems into one unified design.
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 voice recognition accuracy by reducing sound interference, enabling effective voice control in loud environments without the need for increased volume or proximity, and improves stereophonic sound quality with a wider soundstage and reduced noise cancellation.
Implementation Method 1
The card drivers may be of the electrostatic type, such as the electrostatic Venturi membrane-based pump/transducer (EVMP) card type, described and taught in the Pinkerton '073 Application
Implementation Method 2
A dipole speaker design with microphones positioned along a null sound plane, where sound pressure is minimized
Data Source
AI summary
Dipole audio speakers, and more particularly, voice controlled dipole audio speakers having at least one microphone located substantially along the null sound plane of the dipole audio speaker. An improved loudspeaker system that produces an improved audio quality for stereophonic sound. The improved loudspeaker utilizes conventional electro-dynamic drivers in a sealed chamber that produce sound primarily in the 20-300 Hz band coupled with electrostatic card stack drivers placed outside the sealed chamber that cover the remaining 98% of the audio frequency spectrum (300 Hz to 20 kHz). The improved loudspeaker system can also include multiple card stack drivers that are placed at angles with respect to each other to maximize audio fidelity.