MTM Speaker Filtering for Wider Horizontal Audibility
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Solution Overview
Problem
Mid-tweeter-mid (MTM) speaker configurations experience a 'narrowing' phenomenon where audio perception differs significantly between various listening positions, particularly when oriented horizontally, due to interference and inconsistent frequency response.
Innovation Solution
Implementing a digital audio processing system that applies distinct filtering to audio signals for each mid-range speaker based on orientation and configuration, using a combination of filters such as low-frequency shelf, bandpass shelf, low-pass, allpass, and high-frequency shelf filters to ensure consistent audio output across different positions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If MTM speaker configuration is used horizontally, then compact form factor is achieved, but audio consistency and angular audibility deteriorate due to narrowing phenomenon
Solution Approach 1:
The patent applies different filtering characteristics to different speakers within the MTM configuration. Specifically, the first and second mid-range speakers receive different audio signals with different filtering applied, allowing each speaker to compensate for its specific position and the interference patterns it creates, thereby maintaining audio consistency across different listening positions while preserving the compact horizontal form factor
2Device complexity
If identical filtering is applied to both mid-range speakers, then device complexity is reduced, but audio quality deteriorates due to interference and narrowing effect
Solution Approach 1:
The patent implements different filtering characteristics for each mid-range speaker based on its position in the MTM configuration. The first mid-range speaker receives audio signal with first filtering applied, while the second mid-range speaker receives audio signal with second filtering applied, where the filtering characteristics are specifically designed to compensate for interference patterns and maintain consistent audio quality across different listening positions
3Device complexity
If frequency response is not compensated for speaker position, then device complexity is reduced, but harmful interference and narrowing phenomenon increase
Solution Approach 1:
The patent applies preliminary filtering to the audio signals before they reach the speakers, specifically designing the filtering to pre-compensate for the interference that would otherwise occur. By applying different filtering characteristics to the first and second mid-range speakers in advance, the system prevents the narrowing phenomenon and interference from occurring, rather than attempting to correct them after they manifest
Data Source
AI summary
Systems, methods, and apparatus to filter audio are disclosed. An example device includes first and second audio speakers having first audio characteristics, a third audio speaker having second audio characteristics, wherein the third speaker is positioned between the first and second audio speakers, a first audio filter to process an audio input signal to have a first frequency response including a first cutoff frequency, the first audio filter to output a first audio output signal to the first audio speaker, and a second audio filter to process the audio input signal to have a second frequency response to compensate for interference between the first and second frequency responses caused by a position of the first audio speaker relative to the second audio speaker.