Audio Equalization Filtering for Transparent Output Across Headphones
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing audio production systems struggle to provide a transparent and undistorted audible output due to the interaction between audio input and output devices, which is influenced by factors such as impedance and earpad configurations, leading to variable and undesirable sound quality.
Innovation Solution
An audio processor that receives an audio input signal and adjusts it using equalization filtering based on the identified frequency response of the output device, including impedance and earpad type, to compensate for distortion caused by the interaction between the audio input and output devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If equalisation filtering is applied to compensate for output device frequency response, then audio output transparency is improved, but device complexity increases
Solution Approach 1:
The patent applies equalisation filtering in advance to the audio signal before it reaches the output device. The audio processor pre-compensates for the known frequency response characteristics of the output device (headphones, speakers) by applying inverse filtering. This preliminary action ensures that the combined response of the processed signal and the output device produces a flat, transparent frequency response, eliminating the need for manual EQ adjustments or hardware modifications to the output device.
Solution Approach 2:
The audio processor acts as an intermediary device between the audio source and the output device. It receives the audio signal, applies equalisation filtering based on the output device's frequency response characteristics, and outputs the corrected signal. This intermediary processing stage compensates for the output device's frequency response without requiring modifications to either the source or the output device itself, thereby maintaining system simplicity while improving audio transparency.
2Reliability
If hardware configuration is changed to tailor frequency response, then audio output quality is improved, but ease of operation deteriorates
Solution Approach 1:
The system pre-determines the frequency response characteristics of the output device and automatically generates the corresponding equalisation filtering parameters. Instead of requiring users to manually adjust hardware configurations or perform complex calibration procedures, the audio processor automatically applies the appropriate equalisation based on the detected or pre-stored frequency response data, making the process transparent and effortless for the user.
Solution Approach 2:
The audio processor automatically identifies or receives information about the output device's frequency response and self-adjusts the equalisation filtering without user intervention. The system serves itself by autonomously configuring the appropriate compensation filters based on the output device characteristics, eliminating the need for users to manually reconfigure hardware or perform calibration tasks when changing output devices.
3Reliability
If impedance matching is optimized by selecting specific headphone impedance, then audio output transparency is improved, but adaptability deteriorates
Solution Approach 1:
Instead of requiring users to select headphones with specific impedance values to achieve transparent audio output, the patent changes the electrical parameters of the audio signal through equalisation filtering. The audio processor analyzes the frequency response characteristics resulting from the interaction between the output device impedance and the amplifier, and applies compensating filters to achieve a flat overall frequency response. This allows any impedance combination to produce transparent audio output through signal processing rather than hardware matching.
Solution Approach 2:
The patent replaces the traditional mechanical/electrical impedance matching approach with an electronic signal processing approach. Rather than requiring physical compatibility between output device impedances, the system uses equalisation filtering to electronically compensate for impedance-related frequency response variations. This substitution of electrical signal processing for electrical impedance matching greatly enhances compatibility across different headphone and speaker impedances while maintaining audio transparency.
Data Source
Figure 1~2
Figure 3~4
Figure 5
AI summary
There is provided an audio processor (16) suitable for adapting audible output of an output device (18). The audio processor (16) being configured to: receive an audio input signal; receive an identified frequency response of an output device configuration across a frequency range; generate equalisation filtering based on the identified frequency response; and provide an audio output signal to the output device (18), the audio output signal including the audio input signal with the equalisation filtering applied. A corresponding method is also provided.