Noise Reduction Techniques for Audio

By Sarah Okonkwo · September 28, 2026

Types of Audio Noise

Before choosing a reduction method, identify what you're fighting:

Broadband noise: HVAC hiss, tape hiss, fan noise — spread across all frequencies
Tonal noise: AC hum (50/60 Hz), monitor whine, ground loops — concentrated at specific frequencies
Impulse noise: Clicks, pops, mouth sounds — short transient bursts
Environmental: Traffic, keyboard typing, dog barking — unpredictable and intermittent

Spectral Editing

Spectral editors like iZotope RX display audio as a frequency-vs-time spectrogram. You can visually identify and surgically remove noises that would be impossible to isolate with EQ alone.

Common Spectral Tools

Spectral Repair: Interpolates across selected regions using surrounding audio
Spectral De-noise: Learns a noise profile and subtracts it adaptively
De-click: Detects and reconstructs impulse events
De-hum: Tracks and removes harmonic series at specific base frequencies

Adaptive Noise Reduction

Plugin-based adaptive tools (Waves NS1, Cedar DNS, Supertone Clear) process audio in real-time using learned noise models. They're essential for live broadcast and podcast workflows where post-processing isn't feasible.

AI-Powered Tools

Recent AI tools have dramatically improved noise removal quality:

Adobe Podcast AI: Free web tool that removes background noise and room reverb
Goyo / Supertone Clear: Separate voice, ambience, and reverb stems with neural networks
DaVinci Resolve Voice Isolation: Built into Resolve 19, excellent for video post

Prevention Over Cure

The best noise reduction happens before you hit record:

Record in a treated room with HVAC off
Use dynamic mics in noisy environments
Check gain staging — too much gain = more noise floor
Record room tone for spectral subtraction reference

Processing Order

Always apply noise reduction before EQ, compression, or reverb. Processing noise through dynamics and effects makes it louder and harder to remove later.