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.