Headset Side-Tone Filter for Noise Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Headsets often attenuate both environmental noise and the user's own speech, leading to noise pickup in the side-tone, which degrades sound quality and makes it difficult for the wearer to adjust their speaking volume effectively, especially when the microphone is not positioned close to the mouth.
Innovation Solution
A signal processor with a controllable side-tone filter that generates a side-tone signal by computing a noise estimate across frequency bands and adjusts the filter stages to improve the signal-to-noise ratio, using multiple IIR filter stages and a high-shelf filter to attenuate noise while minimizing latency and distortion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the voice microphone is positioned away from the headset wearer's mouth to avoid capturing speech, then environmental noise pickup increases, but speech-to-noise ratio deteriorates
Solution Approach 1:
The patent applies local quality by implementing frequency-selective noise suppression that targets specific frequency bands where noise predominates while preserving speech frequencies. The side-tone filter is configured to attenuate noise in particular frequency ranges rather than uniformly across all frequencies, allowing the microphone to be positioned optimally for speech capture while locally suppressing environmental noise in the side-tone path.
2Loss of time
If a simple side-tone filter is used to provide feedback, then latency is reduced, but noise attenuation capability is insufficient
Solution Approach 1:
The patent implements dynamics by making the side-tone filter characteristics adjustable and adaptive. The filter configuration can be dynamically modified based on noise conditions, allowing optimization of both latency and noise attenuation. The system adapts filter parameters such as cutoff frequencies and gain values to balance real-time response with effective noise suppression in varying acoustic environments.
3Object-affected harmful factors
If aggressive noise suppression is applied to the side-tone signal, then noise in side-tone is reduced, but speech quality and naturalness deteriorate
Solution Approach 1:
The patent applies local quality by implementing frequency-selective noise suppression that targets specific frequency bands where noise predominates while preserving speech frequencies. The side-tone filter is configured to attenuate noise in particular frequency ranges rather than uniformly across all frequencies, allowing the microphone to be positioned optimally for speech capture while locally suppressing environmental noise in the side-tone path.
Solution Approach 2:
The patent applies partial action by implementing moderate, targeted noise suppression rather than aggressive full-spectrum filtering. The side-tone filter is configured to provide just enough noise attenuation in specific frequency bands to improve signal-to-noise ratio while maintaining natural speech characteristics. This partial suppression approach avoids the degradation of speech quality that would result from excessive filtering.
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A signal processor (105) for a headset (101) configured with a microphone terminal (106) for receiving a microphone signal, a loudspeaker terminal (107) for outputting a loudspeaker signal, and a far-end terminal (108) for communicating an inbound signal and an outbound signal with a far-end; comprising: a side-tone path (110) configured to generate a side-tone signal from the microphone signal via a controllable side-tone filter; wherein a side-tone filter controller (114) receives the microphone signal and computes a first noise estimate with a signal-to-noise level of the microphone signal at respective frequency bands and based thereon controls the side-tone filter (111) to improve or optimize a signal-to-noise ratio.