---
title: Single-channel biquadratic filters
framework: accelerate
role: collectionGroup
role_heading: API Collection
path: accelerate/single-channel-biquadratic-filters
---

# Single-channel biquadratic filters

Filter a single-channel signal with a cascade of biquadratic sections.

## Overview

Overview The vDSP library implements biquadratic filtering as a cascade of individual infinite impulse response (IIR) filters called sections. Each section has its own set of feedback and feedforward coefficients, and implements a direct-form 1 filter. When the biquadratic filter function executes, the sections execute in sequence. Each section processes the entire input signal and passes its output to the next section for further processing. note: The vDSP biquadratic filters work in place. That is, the source and destination pointers may point to the same memory.

## Topics

### Biquadratic filter essentials

- [Applying biquadratic filters to a music loop](accelerate/applying-biquadratic-filters-to-a-music-loop.md)
- [Creating an audio unit extension using the vDSP library](accelerate/creating-an-audio-unit-extension-using-the-vdsp-library.md)

### Creating a single-channel biquadratic filter setup

- [vDSP_biquad_Setup](accelerate/vdsp_biquad_setup.md)
- [vDSP_biquad_SetupD](accelerate/vdsp_biquad_setupd.md)

## See Also

### Vector filtering

- [Biquadratic IIR filters](accelerate/biquadratic-iir-filters.md)
- [Multichannel biquadratic filters](accelerate/multichannel-biquadratic-filters.md)
- [Finite impulse response filters](accelerate/finite-impulse-response-filters.md)
- [Recursive filters](accelerate/recursive-filters.md)