An audio joiner app combines multiple audio files into one downloadable file; Audio Joiner specifically joins 2–10 browser-decodable files into one local PCM16 WAV.
The Audio Joiner browser app is designed for combining complete decoded tracks or clips in a deliberate sequence. It does not upload the selected files, mix tracks together, or add production effects. Instead, it creates a new WAV whose samples follow the order shown in the file list.
This workflow suits tasks such as arranging several voice segments into one continuous recording or placing multiple full audio clips into a single playback file. If the real goal is to cut a precise time range, fade between clips, change channels, or preserve compressed audio and metadata, a different editing operation is required.
What the Audio Joiner App Creates
Audio Joiner produces a newly encoded RIFF/WAVE file containing interleaved, little-endian, signed 16-bit PCM samples. The output is a static PCM representation of the browser-decoded audio rather than a container that preserves the source files. Matching channels are retained in their decoded order, and the files are concatenated according to the final visible list.
No inserted silence, overlap, crossfade, normalization, transition, or automatic trimming is applied. The last sample frame from one decoded track is followed immediately by the first sample frame of the next track. This makes the result a direct join, but it also means that poor source boundaries, unwanted room tone, and clicks caused by incompatible edits will remain present.
The WAV is uncompressed, so it can be substantially larger than MP3, AAC, Opus, Vorbis, or FLAC inputs. The output does not retain the original codec, bitrate, encoder settings, tags, album art, chapters, cue points, loop points, loudness fields, timestamps, or other container metadata.
Check Files Against the Join Limits
Check the selection before joining. Audio Joiner enforces explicit input and decoded-audio budgets rather than silently shortening, downsampling, downmixing, or omitting material.
| Requirement | Allowed value |
|---|---|
| Number of files | 2–10 browser-decodable audio files |
| Maximum size per encoded file | 25 MiB, or 26,214,400 bytes |
| Maximum total selection size | 100 MiB, or 104,857,600 bytes |
| Maximum decoded duration | 30 minutes across the selection |
| Maximum decoded channels | 8 channels, with the same channel count in every file |
| Maximum working sample rate | 192 kHz |
| Maximum decoded sample budget | 30 million channel-samples counted across all channels |
A high-rate or multichannel selection can reach the 30-million-sample limit before it reaches the 30-minute duration limit. If any input, duration, rate, channel, frame, or sample-budget check fails, the tool rejects the selection with a specific message. It does not trim tracks or reduce their quality merely to make them fit.
Keep the encoded input sizes within the per-file and total limits before selecting everything together. A file that is individually small enough can still make the complete selection exceed the 100 MiB total.
Join Clips in the Required Order
Use the following workflow in Audio Joiner:
- Open the Audio Joiner interface and select 2–10 browser-decodable audio files together. Confirm that the selection meets the per-file and total size limits before continuing.
- Wait while the browser decodes every selected file. A damaged, encrypted, incomplete, mislabeled, or unsupported file produces a clear error instead of being added to the join.
- Preview each decoded track and confirm that it contains the expected audio. Also check the displayed sample rate; a decoded rate above 192 kHz causes the selection to be rejected.
- Use the Move up and Move down controls until the visible list matches the required playback sequence.
- Select Join in this order. Audio Joiner uses the decoded tracks in the order currently shown rather than sorting them by filename automatically.
- Preview the resulting PCM16 WAV, paying particular attention to the transition between each pair of tracks.
- Download the new WAV and confirm that the file opens correctly before replacing or deleting any source material.
Reordering updates the decoded track order and the visible list together. It also clears an older WAV result, preventing a download from an earlier sequence from being mistaken for the current join.
The order shown in the list is the order written into the output. If files begin with incompatible ambience, a spoken sentence does not logically continue from the preceding clip, or a track starts with a sharp transient, changing the list order will not repair the content itself.
Handle Browser Decoding and Channel Rules
Decoding uses the browser's Web Audio API, including its decodeAudioData capability. The picker recognizes common MP3, WAV, M4A, AAC, Ogg, WebM, and FLAC filenames and MIME types, but a recognized extension does not guarantee that a particular codec variant will decode in Safari, Chrome, Firefox, or another browser. Codec availability depends on the current browser and operating system, and Audio Joiner does not add a codec library or server-side fallback.
All selected files are decoded through the same AudioContext. That shared context can resample source files to one working sample rate, so the rate displayed for the decoded tracks or result may differ from the rate stored in an original file. The final WAV uses the context's working rate and does not preserve separate source sample rates.
Every decoded track must have the same channel count. A selection containing mono and stereo files is rejected rather than silently duplicating, dropping, averaging, or remapping channels. Matching channels are retained in their decoded order and concatenated independently before the WAV channels are interleaved.
If a file fails to decode, first try a current browser and confirm that the file is complete and not encrypted. The error message should distinguish a file the browser cannot decode from a selection that violates the joiner's channel, rate, duration, or sample budgets.
Understand What the WAV Changes
The join operates on samples decoded by the browser. Floating-point samples are converted into the signed 16-bit PCM range, with out-of-range values clipped and non-finite values written as silence. The resulting file is therefore a new encoding, not a byte-for-byte preservation of the source files.
| Task | Audio Joiner behavior |
|---|---|
| Join complete decoded tracks in a chosen order | Supported |
| Insert silence, a fade, an overlap, or a crossfade | Not applied |
| Trim a selected time range automatically | Not performed |
| Normalize levels or match loudness | Not performed |
| Combine files with different channel counts | Rejected with an error |
| Preserve the original compressed codec or container metadata | Not preserved |
For a precise excerpt, use Audio Cutter to cut a time range. A dedicated editor is more appropriate when the task requires fades, loudness matching, channel conversion, compressed output, metadata preservation, or sample-level repair.
Keeping the original files until the join has been checked is particularly important. The new WAV can reveal a source problem that was not obvious during individual playback, such as a clipped first sample, an unwanted noise floor, a mismatched ending, or an edit that does not flow into the next clip.
Verify the Downloaded Result
After downloading, confirm the duration, track order, joins, channel playback, and file size. Listen across every boundary rather than checking only the beginning and end. The joined result should contain each decoded track in the selected sequence, with no material inserted between them.
If playback seems wrong, work through Fix a Result That Looks Wrong After You Join Audio to distinguish an ordering or channel problem from an issue already present in a source file. Remember that the output is uncompressed PCM16, so a larger file than the originals is expected.
Audio Joiner uses temporary local object URLs for playback and the download. Those URLs are released when the selection is replaced or the page closes, so complete the download before closing the tab or choosing a different set of files.
Related reading: Convert Audio Backwards and Download a PCM16 WAV.