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MyMP3 Converter

How to remove background noise from audio on iPhone

Open a converted file on the Audio tab, tap NR, move the strength slider, tap Preview with NR to listen, then Apply NR & Save. It’s a fixed filter that tames low hum and high hiss — it won’t remove voices, traffic or music mixed into the speech.

2 min read · Updated 2026-09-16

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What Noise Reduction actually does

To be upfront: Noise Reduction (Pro) isn’t AI denoising. It’s a fixed filter, three parts — a high-pass cut against low rumble and hum, a low-shelf cut around 200 Hz, a high-shelf cut around 8 kHz against hiss. Push the strength up and all three move further, but the filter still can’t tell a voice apart from any other sound sitting in the same frequency range.

What the strength slider changes
StrengthHigh-pass cutoffLow-shelf @200 HzHigh-shelf @8 kHz
25% (Light)75 Hz-1.5 dB-1.0 dB
50%90 Hz-3.0 dB-2.0 dB
Max (Strong)120 Hz-6.0 dB-4.0 dB

How to reduce noise in a recording, step by step

  1. Get the recording into the app: convert a video, or tap + on the Videos tab to import a voice memo or other audio file, then convert it.
  2. On the Audio tab, tap the file, then NR.
  3. Drag the strength slider between Light and Strong.
  4. Tap Preview with NR to hear the filter live; Stop Preview to turn it off.
  5. Sounds right? Tap Apply NR & Save. A new file with _nr in the name joins the Audio tab; the original is untouched.

What it can and can't fix

  • Good for: a fridge or fan’s low hum, mains hum, wind rumble the mic picked up, and the high hiss of a quiet room or a cheap microphone.
  • Bad for: another voice talking, traffic, music playing behind the speaker, or wind strong enough to sit right in the speech range. All of those overlap the voice itself, and the filter just can’t pull them apart.

Tips and common mistakes

  • Start at Light and preview before going higher; crank it too far and you trade noise for a thinner voice.
  • Noise Reduction is Pro only; free doesn’t show the NR button at all.
  • It needs a file already on the Audio list, not a live recording — convert first, filter after.
  • Another voice or music behind the speaker? Expect little change; it only targets hum and hiss, never other sound sources.

Questions and answers

Can it remove background noise from a voice memo on iPhone?
It can lower hum, rumble and hiss in a voice memo you convert first. It can’t remove another person talking, music or traffic sitting behind the voice.
Is Noise Reduction free?
No, it’s Pro only, reached from a converted file’s NR button or the Tools tab.
Does it use AI to clean up audio?
No. It’s a fixed filter — a high-pass cut plus two shelf cuts — not AI or spectral noise removal, so it only ever targets low hum/rumble and high hiss.
Can I preview it before saving?
Yes. Tap Preview with NR to hear it with the filter on, adjust strength, then Apply NR & Save to keep a new copy.

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