Audio joiner
Make separate sounds work together. Import your audio, place clips on a multitrack timeline and trim or overlap them as you listen. Save the finished mix as one MP3 or WAV.
Import sources, build your timeline and save the mix.
Audio joiner is in your dock. Everything you started is still there.
Your sounds. Your timeline.
Import your sources, place them on tracks and shape the mix as you listen.
Bring the pieces together.
Drop your songs, voice notes or podcast clips here.
MP3WAVM4AAACOGGOPUS+3
A voice up front.
Music underneath.
Every clip in its place.
Import first. Build your timeline next. Nothing plays until you press Play.
Select a clip to edit
Drag a clip to move it. Drag either edge to trim. Overlapping clips play together, even on the same track.
A starting arrangement
Used by Place all in sequence. Existing clips stay in place.
Choose your output
MP3 for sharing. WAV for the next edit.
One finished mix
Save mix in the file bar exports your timeline.
- Mix duration
- 0:00
- Estimated size
- 0 KB
MP3 is re-encoded. Choose WAV for an uncompressed result.
Add audio to start arranging your mix.
Memory limits and keyboard controls
Up to 20 source files, 80 timeline clips and 8 tracks. Each file can be 100 MiB; sources together can be 200 MiB. Decoded audio must fit 256 MiB. The mix can be at most 20 minutes. Sources and edits clear on reload.
Space plays or pauses. S splits the selected clip at the playhead, outside its fades. Delete removes a selected clip. Arrow keys move a focused clip or trim edge by 0.01 seconds, or 0.1 with Shift. Ctrl or ⌘ Z undoes; Shift with Z redoes. Ctrl or ⌘ S saves the mix.
Live playback uses safe headroom when clipping protection is on. Export measures actual sample peaks, so its level may differ. Output sample rate, bit depth and MP3 encoding apply to export.
Audio stays in your browser.Audio stays here. Settings save privately.Saving details
How to join audio files online
- Import your source audio
Choose your songs, recordings or voice notes. They open in a source library without changing your timeline.
- Build and play your timeline
Drag sources onto tracks, trim each clip and overlap audio where needed. Press Play to hear the arrangement.
- Save your finished mix
Choose MP3 or WAV and press Save mix in the file bar. Mixing and encoding happen in your browser.
Using the audio joiner
Your source library and timeline do different jobs. Import everything first, then choose which sounds belong in the mix.
Import sources, then place clips
Choose audio files accepts several recordings at once. Try a musical example imports three generated chords into the library.
| Control | What it does |
|---|---|
| Add more | Imports more sources. Its menu offers paste and From your phone. |
| Source + button | Places the whole source at the playhead on the selected track. Use a source several times without decoding it again. |
| Drag a source | Places a new clip where you let go on a track. The + button provides a touch and keyboard alternative. |
| Place all in sequence | Adds the library after the existing arrangement, on the selected track. Transition settings control direct joins, crossfades or gaps. |
| Remove source × | Removes that source and every clip using it. This releases undo history so the audio can leave memory. |
Edit a multitrack timeline
Drag a clip left or right to move it in time. Drag it vertically to move between tracks.
Drag either edge to trim the source section. Trimming the left edge keeps the remaining audio at its existing timeline position.
Overlapping clips play together, even on the same track. For music under speech, use separate tracks and lower the music volume.
- Add track creates another lane, up to eight. Select its track name before placing a source with +.
- M and S mute or solo a track. Several solo tracks can play together. A muted ending still counts towards the mix duration.
- Snap helps align clip edges, the playhead and tenths of a second. Turn it off for free positioning.
- Zoom and Fit change the timeline scale. Scroll horizontally to reach later clips.
- Undo and Redo reverse clip and track edits. Clear removes the complete project.
Use the clip inspector for exact edits
Select a timeline clip to reveal its settings. The Select timeline clip menu also reaches clips hidden behind an overlap. Time fields use seconds, with sample-clock boundaries applied during export.
| Setting | Meaning |
|---|---|
| Track and Timeline start | Choose the lane and when the clip begins in the mix. |
| Source in and Source out | Choose the section of the original recording to keep. The original file does not change. |
| Volume | Applies a constant gain from -24 to +12 dB. This does not match loudness automatically. |
| Fade in and Fade out | Shape each clip edge. Overlap two clips and fade the outgoing and incoming edges to make a crossfade. |
| Split at playhead | Divides a clip in its unfaded middle. Outer fades stay on the original outer edges. |
| Duplicate and Remove clip | Places a copy immediately after the selected clip, or removes that timeline instance. The source stays in the library. |
Play your edit immediately
Play starts at the playhead without creating an export. Pause keeps your position. Stop returns to the beginning.
Click the ruler or enter a playhead time to seek. Loop repeats the entire timeline. Editing pauses playback.
Live playback uses your clip positions, trims, levels and fades. With protection on, it reserves conservative headroom for overlaps.
Export measures actual mixed sample peaks, so its level can differ from live playback. Output format, rate and depth apply during export.
Save one MP3 or WAV
Save mix exports the arrangement and saves the file. Prepare export to check makes the same file without saving it yet.
- MP3 quality offers 128, 192, 256 or 320 kb/s. Size is estimated until encoding finishes.
- WAV bit depth offers 16-bit or 24-bit PCM. WAV size follows the exact output sample count.
- Sample rate offers 44,100 or 48,000 Hz. Inputs are decoded at 48,000 Hz.
- Channels keeps stereo when present, or averages stereo into mono.
- Prevent sample clipping measures the export and reduces overall gain when needed. This protects sample peaks, not inter-sample true peaks.
- Open in and Share send the finished mix through the file bar. Cancel processing stops an import or export.
Keyboard controls
Space plays or pauses when focus is outside a form or button. S splits a selected clip outside its fades.
Left and right arrows move a focused clip or trim edge by 0.01 seconds. Hold Shift for 0.1 seconds. Up and down arrows change a focused clip’s track.
Delete removes a focused timeline clip. Ctrl or ⌘ Z undoes; Shift with Z redoes. Ctrl or ⌘ O opens files; Ctrl or ⌘ S saves the mix.
What this tool will not do
This editor cannot copy MP3 frames without re-encoding. It has no recording, effects rack, beat matching or automatic voice ducking.
The library holds 20 sources. The timeline holds 80 clips across eight tracks. Each source can be 100 MiB; together they can be 200 MiB.
Decoded samples must fit 256 MiB. The mix can be at most 20 minutes. Sample-rate conversion has a separate 256 MiB working limit.
Browser codecs determine which files open. Protected or unsupported recordings are refused with a reason. Sources, edits and undo clear on reload.
Frequently asked questions
How do I merge MP3 files into one?
Import your MP3 files into the source library. Use Place all in sequence for an end-to-end arrangement, or place them individually on the timeline. Trim and play your clips, choose MP3 under File format and press Save mix. Your original files stay unchanged.
Can I overlap audio and put music under a voice?
Yes. Put the voice on one track and music on another. Set both timeline starts to zero, then lower the music volume in the clip inspector. Any clips whose times overlap play together, including clips on the same track. Mute and Solo help you check each track.
Can I join files in different audio formats?
Yes, when your browser can decode them. Inputs can include MP3, WAV, M4A, AAC, OGG, Opus and FLAC. Decoding happens locally. An unsupported or damaged file is named with a reason, while other sources can still open.
Can I join audio without losing quality?
MP3 output is a new lossy encode. WAV avoids another lossy encoding after decoding, but cannot restore detail removed from an MP3. This editor decodes sources to trim, mix and fade them. Compatible MP3 files needing only concatenation may suit FFmpeg stream copy. The guide explains that tradeoff.
How do I make a crossfade between songs?
Choose Crossfade and a duration under A starting arrangement, then press Place all in sequence. This adds overlapping clips with matching fade-in and fade-out envelopes. You can also move two clips to overlap and set their fades in the inspector. Equal power suits different music; Linear can suit similar sounds. Automatic sequence crossfades use at most half of each neighbouring clip.
Does this audio joiner upload my recordings?
No. Reading, decoding, playback, mixing and encoding happen in your browser. Audio, filenames, timeline edits and previews stay in this tab. Signed-in accounts can save global output and transition settings. Google Analytics never reads your audio. The privacy page explains the site’s separate analytics services.
Can I edit voice notes on my phone?
Yes, when your browser supports their codecs. Import your notes, then use each source’s + button or Place all in sequence. Select a clip and use the inspector for exact position, trim and volume changes. The timeline scrolls horizontally. Your phone may need smaller groups to fit its memory.
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