Parametric EQ Control Using Polynomial Curve Fitting

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Solution Overview

Problem

Existing audio equalizers, particularly parametric equalizers, are complex to control and often left at predefined settings, failing to provide personalized audio experiences for everyday users.

Innovation Solution

A method for controlling audio equalizers using a polynomial EQ function derived from a limited number of EQ control indicators, allowing for intuitive adjustment of frequency and gain, with optional tilt indicators for simple customization, and processing to maintain consistent volume levels.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a parametric equalizer is used to provide greater freedom of control, then audio customization capability is improved, but control complexity increases making it difficult for everyday users

Engineering Contradiction:
Improveaudio customization capabilityVSAvoidcontrol complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent segments the complex parametric equalizer control into two distinct layers: a simplified user interface layer with limited controls (e.g., preset buttons, simple sliders) and a sophisticated processing layer that implements full parametric equalization. This segmentation allows everyday users to access advanced audio customization without being overwhelmed by the underlying complexity, as they only interact with the simplified layer while the system automatically manages the complex parameters.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces an intermediary processing layer that translates simple user inputs into complex parametric equalizer settings. This intermediary automatically converts user-friendly control actions (such as selecting a preset or adjusting a single slider) into multiple parametric adjustments (frequency, bandwidth, gain) that would otherwise require manual configuration. This mediator handles the complexity transformation, allowing users to benefit from advanced equalization without directly managing complex parameters.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If more EQ control parameters are determined to provide finer control, then audio precision is improved, but processing power is wasted

Engineering Contradiction:
Improveaudio control precisionVSAvoidprocessing power consumption
Core Design Contradiction:
Measurement precisionVSUse of energy by moving object

Solution Approach 1:

The patent implements partial action by determining the minimum necessary number of EQ control parameters required to achieve the desired audio effect rather than calculating all possible parameters. The system analyzes the polynomial EQ function and identifies only the essential frequency and gain parameters needed for effective equalization, leaving out redundant calculations. This approach maintains audio control precision while significantly reducing processing power consumption by performing only the necessary computations.

Inventive Principle:
Principle #16Partial or excessive action

3Reliability

If polynomial EQ function is used to smooth gain changes, then sound quality is improved, but computational complexity increases

Engineering Contradiction:
Improvesound qualityVSAvoidcomputational complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies preliminary action by pre-calculating and storing polynomial EQ functions that provide smooth gain transitions. Instead of performing complex polynomial calculations in real-time during audio processing, the system pre-computes these functions offline and stores them for rapid retrieval and application. This preliminary preparation maintains high sound quality with smooth gain changes while dramatically reducing the computational complexity during actual audio playback, as the heavy mathematical work has already been completed in advance.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP4616531B1Equalizer control
Publication Date: 2026.03.04 AUDIODO AB (PUBL)
  • EP4616531B1 patent drawingFigure 1a~2d
  • EP4616531B1 patent drawingFigure 3a~4
  • EP4616531B1 patent drawingFigure 5~7

AI summary

A method of controlling an audio equalizer, EQ, (100) arranged to process an audio stream (10) is presented. The method comprises obtaining a number of EQ control indicators (i1,..., in) for control of the audio EQ (100), each EQ control indicator (i1,..., 5 in) comprising a frequency and a gain. The method further comprises curve fitting between the EQ control indicators (i1,..., in), thereby providing a polynomial EQ function (p) describing a preferred gain (G) versus frequency (f) behavior of the audio EQ (100), and determining a number of EQ control parameters (c1,..., cm) based on the polynomial EQ function (p). Each EQ control parameter (c1,..., cm) comprises a frequency and a gain, and wherein the number of EQ control indicators (i1,..., in) is at least two, and the number of EQ control parameters (c1,..., cm) is greater than the number of EQ control indicators (i1,..., in). The method further comprises providing the EQ control parameters (c1,..., cn) for control of the audio EQ (100).