Frequency-Dependent Attenuation Tuning for Audio Distortion Control
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Solution Overview
Problem
Existing audio reproduction systems suffer from non-linear distortion, which affects sound quality by changing timbre and phase with sound amplitude, and current methods to suppress this distortion often compromise loudness or introduce timbral changes.
Innovation Solution
A device and method for tuning a frequency-dependent attenuation stage that detects non-linear distortion and applies psycho-acoustic compensation to control the attenuation stage, optimizing the balance between distortion suppression and loudness by considering audibility and masking thresholds, and using machine-learning for dynamic range control detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a dynamic range limiter is used to suppress non-linear distortion, then distortion is reduced, but system loudness is sacrificed
Solution Approach 1:
The patent applies different attenuation levels to different frequency bands based on their individual distortion characteristics. Each frequency band is analyzed separately and attenuated only if it exhibits non-linear distortion, allowing undistorted bands to maintain full loudness while distorted bands are selectively suppressed.
Solution Approach 2:
The system dynamically adjusts attenuation in real-time based on the input signal characteristics. The frequency-dependent attenuation stage continuously monitors for non-linear distortion and adapts its transfer function accordingly, applying attenuation only when and where distortion is detected rather than using a fixed attenuation profile.
2Object-affected harmful factors
If multi-band limiting is applied to suppress distortion in specific frequency bands, then distortion is reduced, but timbral changes occur
Solution Approach 1:
The system uses feedback from distortion measurement to control attenuation. The frequency-dependent attenuation stage is tuned based on measured non-linear distortion characteristics, and the transfer function is adjusted according to the detected distortion levels, creating a closed-loop system that preserves timbre while suppressing distortion.
Solution Approach 2:
The patent changes the transfer function parameters of the frequency-dependent attenuation stage based on measured distortion characteristics. The attenuation profile is dynamically adjusted to match the specific distortion behavior of the audio reproduction system, ensuring minimal impact on the original signal timbre.
Data Source
AI summary
A device (160) and a method are proposed for tuning a frequency-dependent attenuation stage (122), with the purpose of suppressing non-linear distortion occurring in an audio reproduction system (120) associated with the frequency-dependent attenuation stage. The device comprises a receiving section (162) adapted to receive data representing an output acoustic signal (140) from the audio reproduction system, recorded upon excitation of the audio reproduction system by a predetermined input data signal (110)a first distortion detection section (163) adapted to detect presence of non-linear distortion based on the received data and to apply psycho-acoustic compensation to the detected non-linear distortion and a control section (164) adapted to determine, based on the psycho-acoustically compensated non-linear distortion, control information (170) suitable for controlling the frequency-dependent attenuation stage.