Fix Zoom audio in a recorded call
Diffio fixes Zoom audio after the call is over: upload the recording from Zoom, Microsoft Teams or Google Meet, and get the speech back restored, in audio or video.
Clean up a recorded call
Drag an audio or video file here, orPick an audio or video file from your phone
MP3, WAV, M4A, AAC, FLAC or OGG audio, or MP4, MOV, AVI, MKV or WebM video. Up to 90 minutes and 2 GB per file.
Free plan: 3 uploads, audio or video, with a 2-minute preview of each result. Downloads and the Pro model from $8 per month.
The guest was on a laptop mic across the room, the connection kept dropping and the air conditioner was louder than anyone expected. The meeting is over and the recording is what you have, so restore that file and hear it next to the original. Diffio works on recordings only; it doesn’t touch a live call.
A video call recording, before and after
One simulated call, built so every problem in it is known: a laptop mic in a small room with an air conditioner running, sent through a low-bitrate call codec that drops packets. Press play, then switch versions. Your place in the clip stays the same.
Thin laptop mic and codec artifacts · Simulated video call
Press play, then switch between Original and Restored. Your place stays the same.
Listen for: The original is thin and boxy, with a watery warble on syllables where the codec lost packets. The restored speech is fuller, with fewer codec artifacts.
Simulated video call: clean speech (LibriTTS, CC BY 4.0) shaped like a laptop microphone, placed in a real measured hotel-room impulse response (BUT Speech@FIT Reverb Database, CC BY 4.0) with a real air-conditioner recording (by sonically_sound, Freesound, CC0), then sent through the Opus codec at 6 kbps with bursty packet loss filled in by the decoder's concealment. Restored with Diffio 4.6 Pro. Both clips are loudness-matched for playback.
Sources: LibriTTS, CC BY 4.0, BUT Speech@FIT Reverb Database, CC BY 4.0, “Air Conditioner” by sonically_sound, CC0. Full credits
How these comparisons were made
The speech is a LibriTTS reading of a public domain audiobook (CC BY 4.0). We shaped it like a laptop microphone, placed it in a measured hotel-room impulse response from the BUT Speech@FIT Reverb Database (CC BY 4.0), mixed in a real air-conditioner recording (CC0) and sent it through the Opus codec at 6 kbps with bursty packet loss. The restored file is Diffio 4.6 Pro’s restored speech with no background mixed in. Each version has one fixed volume change so both play at about the same loudness. Full credits and the sample record are published with the files.
Why recorded calls sound worse than the room did
- Laptop and webcam mics. They sit an arm’s length away and hear the room as much as the voice, so speech comes back thin and hollow.
- Live noise suppression that guesses. Zoom, Teams and Meet filter noise while you talk. When the filter can’t tell a voice from a fan, it trims the starts and ends of words or lets the noise pump in and out.
- Automatic gain. The app turns quiet talkers up as they speak, so the room noise rises in every pause.
- Codec compression. To fit the connection, the call squeezes each voice into a small stream. On a weak connection the squeeze gets harder: high frequencies go and speech turns watery or robotic.
- Dropped packets. When parts of the stream don’t arrive, the app fills the gap with its best guess. You hear a warble, a stutter or a missing syllable.
- Echo. One person on laptop speakers in a bare room, and voices come back a moment later.
What Diffio fixes in a call recording
Diffio restores the speech in the recording you downloaded. Upload it as audio or video and compare the restored speech with the original on one playhead.
- Thin, boxy laptop-mic sound, which comes back fuller. More on fixing bad microphone audio.
- Codec artifacts: the watery, robotic edge of a squeezed connection, as in the sample above.
- Background noise such as fans, air conditioning, keyboards and traffic. See removing background noise from video.
- Room echo from a bare office or a kitchen. See removing echo from audio.
What it can’t do: a word that never made it through the connection isn’t in the recording, and Diffio doesn’t add words. Two people talking at once stay together in one restored speech track, because Diffio doesn’t separate speakers. Results depend on the recording, so check the restored speech against the original before you publish or quote it.
For recordings, not live calls
Diffio isn’t a call filter. It works on a recording after the meeting ends, so it can’t help the people on the call while it’s happening. For a noisy live call, turn on your meeting app’s noise suppression or use a live filter such as Krisp, which is built to clean your microphone during the call. The Krisp and Diffio comparison explains where each one fits.
They also work together: a live filter during the meeting, then Diffio on the recording you share or publish afterwards.
How to fix the audio in a Zoom, Teams or Meet recording
- Get the recording. Zoom saves local recordings to your computer and cloud recordings to your Zoom account. Teams saves meeting recordings to OneDrive or SharePoint, and Google Meet saves them to the organizer’s Google Drive. Each gives you an MP4.
- Upload the MP4 or an audio file. Diffio takes MP4, MOV, AVI, MKV and WebM video and MP3, WAV, M4A, AAC, FLAC and OGG audio, up to 90 minutes and 2 GB per file. Video works on every plan, including Free.
- Choose a model. Diffio 4.6 Flash is fast and on every plan. Diffio 4.6 Pro is the one for a badly compressed call like the sample above, and the Pro model is included in Basic.
- Compare the restored speech with the original on one playhead. If it sounds too dry, the Background amount slider brings some of the room back.
- Download the same video with the restored speech, or the restored speech as WAV or MP3, on a paid plan. Every result also comes with a transcript of the call.
Record the next call better
- Get the mic close. A headset or a USB mic a hand’s width from the mouth does more than any setting.
- Ask each guest to record their own mic with a phone voice memo or their computer, then line the files up afterwards. Their side never passes through the call codec. Podcasters call this a double-ender.
- Save separate audio files. Zoom can record a separate audio file for each participant, which keeps one person’s noise off everyone else’s track.
- Use a wired connection when you can. Fewer dropped packets means fewer warbles in the recording.
- Mute when you’re not talking, and move away from fans, open windows and the kitchen.
Questions about Zoom and video call audio
How do you fix audio on Zoom?
During a meeting, open Zoom’s audio settings, pick the right microphone, test it and set background noise suppression. Those settings can’t change a recording you’ve already made. For that, upload the recording to Diffio, compare the restored speech with the original and download it on a paid plan.
How do I improve the quality of a Zoom recording?
Before you record, get the mic close to each speaker, use a wired connection and ask guests to record their own side. After you record, restore the speech in the file with Diffio. The interview audio cleanup page covers remote interviews and podcast guests in more detail.
Does Zoom have noise cancellation?
Yes. Zoom’s audio settings include background noise suppression that you can set to different levels. It works on the live call. It can’t clean a recording after the fact, and set high it can trim the ends of words.
How do I get just the audio from a Zoom recording?
Zoom’s local recordings save an audio-only M4A file next to the MP4, and cloud recordings include one when the audio-only option is on in your recording settings. You can upload the M4A to Diffio, or upload the MP4 and keep the picture.
Can Diffio fix my audio during a live call?
No. Diffio works on recordings after the call, not on a live microphone. For live calls, use your meeting app’s noise suppression or a live filter such as Krisp. See the Krisp comparison.
Does it work on Microsoft Teams and Google Meet recordings?
Yes. Teams and Meet recordings are MP4 files, and Diffio restores the speech in them the same way it does for Zoom. Recordings from Webex, Riverside, Skype and phone calls work too.
Can Diffio bring back words that cut out?
No. If a word was lost on the connection, it isn’t in the recording, and Diffio doesn’t add words. It makes the words that did come through easier to follow, so check quotes against the original.
Is it free to try?
Yes. The Free plan includes 3 uploads, audio or video, with a 2-minute preview of each result on Diffio 4.6 Flash. Full playback, downloads and the Pro model start with Basic at $8 per month. See plans and limits.
The meeting is over. The recording can still sound better
Upload your toughest call and hear the restored speech next to the original. Results depend on the recording, which is why the first 3 are free.