Restore Old Speech Recordings with AI
A grandparent's interview on cassette. A decades-old lecture series. A radio broadcast nobody has heard clearly in years. Old speech recordings carry voices you can't record again, but hiss, hum, room echo, and wear can make them hard to listen to.
Diffio is AI speech restoration for compromised recorded speech. Upload a digitized recording, restore the voice, and compare the result against the original in the same player.
Try Diffio free: 3 uploads with a 2-minute preview →Hear a 1935 broadcast restored
The proof is in the listening. On Diffio's features page, you can switch between a 1935 Amelia Earhart broadcast and its Diffio restoration while it plays. On Can this noisy recording be saved?, you can compare the same minute of an archival lecture as the original, Diffio 4.5 Flash, and Diffio 4.5 Pro.
Diffio has also published a comparison on archival speech. On 100 matched 30-second Voices for Christ archival sermon clips, Diffio 3.5 measured a 22.5% greater average SCOREQ improvement over the degraded originals than Adobe Podcast. Diffio ran this comparison on March 17, 2026, with an earlier model. SCOREQ is a model-predicted proxy, not a human listening score. See the methodology and matched clips.
What Diffio restores in old recordings
Diffio's custom in-house models focus on spoken audio. For old recordings, that covers:
- Background noise and hiss that sits under the voice
- Room echo and reverb from halls, churches, and classrooms
- Some clipping and distortion (supported cases)
- Low-bandwidth or low-sample-rate speech, which Diffio's restoration docs list as in scope
What it's not
Diffio restores speech. It isn't a music restoration or vinyl remastering tool, and it doesn't digitize tapes. You'll need to transfer cassettes, reels, or records to a digital file first. No result is guaranteed: speech that's heavily masked, clipped, or missing may stay imperfect. Always compare against the source and listen for altered words.
How to restore an old recording
- Digitize the source to a file. Diffio accepts MP3, WAV, M4A, AAC, FLAC, and OGG audio, and MP4, MOV, AVI, MKV, and WebM video, up to 2 GB and 1.5 hours per file.
- Create a project in Diffio and upload it. Add a description so you can keep the archive organized.
- Choose an engine. Flash is on every plan. Pro (paid plans) restores every window three times and keeps the cleanest result. Diffio recommends Pro for damaged speech.
- Compare and keep the original. Projects keep the source beside each restoration, and one project can hold several generations, so the original is never lost.
- Download the restored speech on a paid plan.
Tips for archival audio
- Transfer at the best quality you can. WAV or FLAC is better than a re-compressed MP3.
- Split recordings longer than 1.5 hours into parts before uploading.
- Keep your raw transfer. Treat restoration as a new version, never a replacement.
- Use Pro for the hardest material.
- Use transcripts when available. A completed generation may include one, which helps when you're cataloging. Transcripts aren't guaranteed for every file.
Old video with poor sound
Digitized home video, old conference talks, and archived webinars can go straight in. Diffio restores the speech soundtrack and leaves the picture unchanged. See video noise removal.
Who restores old recordings with Diffio
- Families and oral historians preserving interviews
- Libraries, ministries, and archives with lecture and sermon collections
- Documentary and podcast producers using archival clips
- Developers processing large archives through the Diffio API, with JavaScript and Python SDKs and webhooks, metered separately
Pricing
The Free plan includes 3 trial uploads with a 2-minute preview of each result. Basic ($8/month) includes 360 minutes per month and Pro ($29/month) includes 1,800 minutes per month, both with full playback and downloads. See current prices.
Frequently asked questions
Can AI restore old audio recordings?
For speech, often yes. Diffio reduces noise, echo, and some distortion in spoken recordings. Results depend on the source, so preview yours first.
Can Diffio restore old music or vinyl?
No. Diffio is built for spoken audio, not music.
Do I need to digitize my tapes first?
Yes. Diffio works on digital audio and video files. Transfer the tape or record to a file such as WAV first.
How long can a recording be?
Up to 1.5 hours and 2 GB per file. Split longer recordings into parts.
Will I lose my original?
No. Each project keeps the source recording available beside its restorations.
Does it work on non-English recordings?
Both Diffio 4.5 Flash and Diffio 4.5 Pro are listed as multilingual.
Is it free to try?
Yes. You get 3 trial uploads with a 2-minute preview of each result.