# Speech Processor

The Speech Processor effect in EasyEffects is powered by the SpeexDSP library, a lightweight and efficient audio processing toolkit originally derived from the Speex codec project. The Speech Processor provides real-time voice enhancement features suitable for telephony, voice chat, or low-resource environments.

# State Settings

## Noise Suppression

Reduces steady background noise such as fan hum or air conditioning. This feature uses spectral subtraction algorithms implemented by SpeexDSP to attenuate non-speech components while preserving intelligibility.

## Automatic Gain Control (AGC)

Automatically adjusts the input gain to maintain consistent voice volume, regardless of the speaker’s distance or tone. This ensures a stable output level for speech clarity.

## Voice Activity Detection (VAD)

Detects whether the incoming signal contains speech. When inactive (i.e., during silence or noise), processing is minimized to save resources and reduce unwanted output.

## Dereverberation

Reduces reverberation caused by reflective environments (e.g., tiled rooms or large halls). This improves speech clarity by suppressing echo tails.

# Voice Activity Probability Settings

## Start

Sets the threshold for transitioning from non-speech to speech. A higher value makes detection more conservative.

## Continue

Sets the threshold for remaining in the speech-detected state. A higher value reduces the chance of speech drop-out.

# Noise Suppression Settings

## Level

Defines how aggressively noise suppression is applied. Lower (more negative) values provide stronger noise removal but may affect voice quality.

# Summary

The Speech Processor is a lightweight and versatile solution for real-time speech enhancement, especially suited for:

Voice calls

Online meetings

Embedded systems or low-power devices

Its combination of noise suppression, AGC, VAD, and dereverberation provides a practical and efficient toolchain for improving voice intelligibility in challenging environments.

# References

The Speex Project