How to remove hum and hiss from a recording
To remove hum or hiss from a recording, import it into Denoise and tap Denoise with the default AI · Auto engine: the AI model on your phone removes steady noise such as fan and air-conditioning hiss, fridge and mains hum and electronic buzz while keeping the voice. If a hum is still there, the Classical engine lets you mark a few seconds of noise so it removes exactly that sound.
Last updated · By Routes Software, the makers of Denoise
Remove hum and hiss in three steps
Import the recording
Tap + and choose Import from Files or Import from Gallery, or share an audio file or video to Denoise from another app.
Tap Denoise
Keep AI · Auto and tap Denoise, then switch between Original and Cleaned. Steady hiss is usually gone after one pass.
Save the result
Tap Share Cleaned to send it to any app, or Save to Files… to keep an M4A (MP3 and WAV are options).
Hear the difference
Good to know
- If a low hum survives, choose the Classical engine, mark a stretch where only the noise can be heard under Noise profile, and tap Denoise. The EQ can also turn down the low frequencies where hum sits.
- Denoise is built for speech. On music, the AI engines can dull the instruments as well, so use Classical for hiss on music.
- Hum from a bad cable or a ground loop is easiest to fix at the source: if you can record again, change the cable or the power supply.
Frequently asked questions
What is the difference between hum and hiss?
Hum is a low, steady tone, usually from mains power at 50 or 60 Hz plus its overtones. Hiss is a high, airy noise from microphone preamps, fans or old tape. Denoise removes both from speech.
Can it clean old cassette or tape recordings?
For speech, yes: digitise the tape, import the file and tap Denoise. For music on tape, use Classical and listen carefully.
Will it also remove music in the background?
AI · Auto reduces background music behind a voice. To fully keep or remove music, use AI · Music, which separates the two.
Is it free?
Importing, cleaning and listening are free, with no account. Saving or sharing the result needs Denoise Pro: $2.99 a month or $14.99 once (US prices, October 2026; the store shows yours before you pay).