Have a story told across ten WhatsApp voice notes, three takes of a podcast intro, or a set of clips you want as one continuous track? The audio joiner merges them into a single file in the order you choose, with smooth crossfades or neat gaps between them.
How it works
- Add two or more audio files. You can mix MP3, WAV, M4A, voice notes and video soundtracks.
- Put them in order with the up and down buttons.
- Choose a crossfade so each clip blends into the next, or a short gap of silence between them.
- Press join, preview the result and download one MP3 or WAV.
Frequently asked questions
How many files can I join?
Up to 20 files, as long as the result is no longer than 10 minutes on the free tool. Files with different sample rates or mono and stereo files can be mixed; we convert them to a common format automatically.
What does crossfade mean?
A crossfade fades the end of one clip out while the next fades in, so they overlap and blend, as a DJ does. Choose 0 seconds for a straight cut, or add a gap of silence instead if you want a pause between clips (for example, between voice notes).
Can I make a medley or DJ mix with it?
You can join sections you have cut with the MP3 cutter and blend them with crossfades. For songs in different keys or tempos, check them first in our Beat Lab BPM and key finder. Only share mixes of music you have the rights to.
Which file types work?
Anything your browser can play: MP3, WAV, M4A and AAC work almost everywhere, and FLAC, OGG and OPUS work in most browsers (for Opus voice notes we include a fallback decoder). You can also choose an MP4, MOV or WebM video and the tool uses its soundtrack. Old AMR voice recordings are not supported by browsers.
Is my audio uploaded anywhere?
No. Your file is opened and processed inside your browser on your own phone or computer. It is never sent to Centertainment or anyone else, so unreleased songs and private voice notes stay with you. The page only downloads the tool itself (and a small MP3 encoder file) from our site.
Is Audio Lab free?
Yes. Every tool on this page is free, with no sign-up, no watermark and no daily limit. Free files can be up to 10 minutes long (8 minutes for the vocal remover). A Pro version with high-quality cloud stem splitting, batch processing and longer files is planned; you can join the waitlist, and nobody is charged anything today.
Terms of use and copyright
- Only process audio you own or have permission to use: your own recordings, beats you have licensed, or tracks whose licence allows editing. Removing vocals, cutting or converting a song does not give you any rights to it.
- Don't publish, sell, stream or perform results made from other people's music without permission from the rights holders. Platforms may mute, block or claim such uploads, and you are responsible for how you use what you make.
- Audio Lab does not download or fetch audio from links (YouTube, TikTok, Instagram, Spotify, Audiomack, Boomplay or anywhere else) and does not host any music. You choose files that are already on your device.
- Your files are processed in your browser and never uploaded to Centertainment. We don't see, store or keep copies of your audio. Voice notes may contain other people's voices: respect their privacy.
- The tools are provided free and "as is". Results are automatic and can contain artefacts, so check them before you share, and keep your original files.
How to merge audio files
- Add two or more files. Mix and match MP3, WAV, M4A, OGG, OPUS voice notes and video soundtracks.
- Use the arrow buttons to put them in order, and the cross to remove any you don’t need.
- Pick a crossfade (from half a second to five seconds) to blend each clip into the next, or a short gap of silence to keep them separate.
- Press Join them, listen to the preview, then download one MP3 or WAV.
Crossfade or gap?
Crossfades suit music: the end of one track fades out while the next fades in, like a DJ blend, so there is no awkward silence. Gaps suit speech: when you join voice notes or interview answers, half a second of silence between them keeps them easy to follow. If the clips were cut from one recording, choose no crossfade and no gap for a seamless join.
Mixed formats are fine
Voice notes are usually mono at 48 kHz; songs are stereo at 44.1 kHz. The joiner converts everything to 44.1 kHz stereo before it joins, so the result plays at the right speed everywhere. Up to 20 files and 10 minutes in total on the free tool, all processed on your device without uploading.
Need to trim each clip first? Use the MP3 cutter. Joining voice notes? Convert them on their own with the voice note to MP3 converter if you just need playable files. Only join audio you own or have permission to use.