biquad-filters

What problem does it solve?

The Biquad Filter Design skill provides a rigorous, reusable approach to creating second-order IIR filters for audio DSP, enabling precise tone shaping, crossovers, and EQ with stable, efficient implementations.

Core Features & Use Cases

• Coefficient calculation: uses Audio EQ Cookbook formulas to derive b0, b1, b2, a1, a2 for common filter types.
• Transposed Direct Form II (TDF2): implements a numerically stable structure with minimal memory.
• Cascading & stability: supports multi-stage filtering with proper ordering for numerical stability.
• Real-time parameter smoothing: includes exponential smoothing to avoid clicks during parameter changes.
• JUCE IIR patterns: demonstrates integration with JUCE DSP patterns for production-ready code.
• Reference implementations: provides example code blocks for low/high-pass, band-pass, notch, peak, and shelves.

Quick Start

Design a low-pass biquad at 1 kHz with Q = 0.707 and apply it to the current audio chain.