Free Audio Joiner
Join audio clips with trimming, gaps, crossfades, fades and loudness normalization locally.
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How to join audio clips with fades and precise trimming
Build one continuous audio file from several recordings or music clips. Preview your sources, set clip ranges and use transitions suited to the material.
- Choose up to eight audio-only files and arrange them in playback order.
- Set start and end points for any clips that need trimming.
- Choose output format, gaps or crossfades, fades and optional normalization.
- Join the clips, preview the result and download the finished audio.
Who the audio joiner helps
Podcasters often record an intro, the main interview and an outro as separate files. Joining them in a fixed order with a short pause between parts gives one episode file that is ready for review.
Teachers and trainers can combine several short voice notes into one lesson track. Musicians and video editors can build a rough medley or a background bed from a few clips, using crossfades so one piece blends into the next.
It also suits anyone who wants to cut the dead air at the start or end of a recording. Each clip has its own start and end time, so you can trim and join in one pass instead of opening a separate editor.
A worked example with real numbers
Say you add three clips that last 30, 45 and 60 seconds, with no trimming. The raw total is 30 + 45 + 60 = 135 seconds.
With a 2 second silent gap, the tool inserts silence between each pair of clips. Three clips have two joins, so the result is 135 + (2 x 2) = 139 seconds. With a 3 second crossfade instead, each join overlaps the end of one clip with the start of the next, so the result is 135 - (2 x 3) = 129 seconds.
For the 129 second version saved as MP3 at 192 kbps, the audio data is about 129 x 192,000 / 8 = 3,096,000 bytes, or roughly 3.1 MB. The same length saved as WAV uses 16-bit stereo at 48 kHz, which is 48,000 x 2 channels x 2 bytes = 192,000 bytes per second, or about 24.8 MB in total. FLAC usually lands between the two, depending on the material.
How the joining and loudness steps work
Every clip is decoded and resampled to 48 kHz stereo, so files with different sample rates or channel counts can sit side by side. Gaps are generated as true digital silence. Crossfades use matching triangular curves on both clips, which gives a simple, even blend.
The fade in applies to the very start of the joined file and the fade out to its very end. The gain setting runs from -24 dB to +12 dB. The normalize option aims the whole file at about -16 LUFS integrated loudness with a -1.5 dB true peak target, a level commonly used for spoken audio online.
Processing happens in a local worker on your device. The combined length of all clips is capped at 15 minutes, and the files you add can total up to 100 MB.
Common mistakes to avoid
Do not try to use a gap and a crossfade together. The tool expects one or the other, and a crossfade must be shorter than half of every clip, so a very short sting or sound effect can block a long crossfade.
Remember that an End value of 0 means the end of the file, not zero seconds. If you type an end time earlier than the start time, the clip cannot be trimmed correctly. Also, adding a lot of positive gain after normalizing can push peaks into clipping, so play the result before you download it.
Finally, joining several MP3 files and saving as MP3 again re-encodes the audio. If you plan more editing later, save a WAV or FLAC working copy and keep your original recordings.
Useful tips and limitations
- Use either silent gaps or crossfades. Crossfades must be shorter than half of every clip.
- Clips are processed at 48 kHz stereo. Listen for clipping after gain changes and keep source recordings.
- Use Move up and Move down to fix the order before joining, because any change to clips or settings clears the previous result.
- For speech, a gap of 0.5 to 1 second between segments usually sounds more natural than a crossfade.
Common questions
Can I join different audio formats together?
Yes, when the local decoder supports the source codecs. The tool decodes clips and encodes a shared MP3, WAV or FLAC output.
Does FLAC joining recover lost audio detail?
No. FLAC is lossless for the processed samples, but cannot restore information already lost in the original recordings.
Which MP3 bitrates can I pick for the joined file?
You can choose 128, 192, 256 or 320 kbps. The bitrate setting only applies when MP3 is the output format.
Can I raise or lower the overall volume?
Yes. The gain field accepts values from -24 dB to +12 dB, and you can combine it with the optional loudness normalization toward -16 LUFS.
Is there a limit on total length?
Yes. The combined duration of your clips can be up to 15 minutes, and the added files can total up to 100 MB.
The shared engine loads from this site and processes audio in a local worker. Audio is not uploaded.