Audio Merger

Source audio:

Choose 2–8 browser-decodable audio files. Each file may be up to 12 MiB; the combined selection may be up to 24 MiB and 60 seconds.

Play order:

Preview a source, then use the arrow buttons to place it in the intended sequence.

{{ clip.file.name }} {{ formatBytes(clip.file.size) }}

Create one reviewed local WAV.

Silence between files:

The neutral default is 0 seconds. Choose up to 2 seconds between each adjacent pair.

seconds

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Timeline review:

The chart renderer is unavailable. The same duration values remain available in the clip timeline.

Order	Source	Start	End	Duration	Audio	Copy
{{ row.order }}	{{ row.name }}	{{ row.startDisplay }}	{{ row.endDisplay }}	{{ row.durationDisplay }}	{{ row.audioDisplay }}

Joining audio means placing complete recordings one after another on a shared timeline. It suits podcast chapters, interview segments, voice notes, announcements, rehearsal takes, and other short clips that already have the right content but need one playback order.

The seam between clips matters as much as the order. An immediate join can sound natural when the first clip ends cleanly and the next begins with room tone. A short silent gap can separate chapters or instructions, but too much silence makes the result feel interrupted.

Order decides what the listener hears next.
Gap inserts silence between adjacent clips, never before the first or after the last.
Channel count determines whether the result is mono or stereo.
Sample rate and bit depth describe the output's time resolution and sample storage, not its artistic quality.

Concatenation does not mix clips on top of one another, crossfade their boundaries, match their loudness, remove noise, or preserve compressed source codecs. Sudden changes in level, background sound, stereo width, or microphone tone remain audible unless they are corrected before the merge.

Keep the original recordings and listen through every join. A valid WAV confirms the file structure and timeline; it cannot tell whether a pause sounds natural or a chapter starts at the intended word.

How to Use This Tool:

Choose short mono or stereo files, place them in listening order, and decide whether each join needs silence.

Select 2 to 8 browser-decodable WAV, MP3, M4A, AAC, OGG, FLAC, or WebM files. Each file may be up to 12 MiB; the selection may total 24 MiB and 60 seconds including gaps.
Move clips until their listed order matches the intended program. Preview a source when its filename does not make the content obvious.
Set Silence between files from 0 to 2 seconds. Start at 0 and add a small pause only when adjacent clips run together.
Merge the files, then check the duration and clip timeline. If a file has an unrecognized signature, cannot be decoded, has more than two channels, or pushes the timeline beyond 60 seconds, replace or shorten it.
Play the merged audio and listen across every boundary before downloading the WAV. Preview volume changes playback in the tab, not the samples written to the file.

Interpreting Results:

The total duration equals the decoded clip durations plus one gap for each join. Clip start and end times should follow the selected order without overlap. A longer result than expected usually comes from the gap being applied between every adjacent pair.

Peak amplitude is the largest absolute decoded sample value on a 0 to 1 scale. A value near 1 shows that at least one sample reaches the available PCM range; it is not an integrated loudness reading and does not prove clipping elsewhere in the recording chain.

The output channel count is two when any source is stereo. Mono clips are copied into both output channels in that case. Listen for level and stereo changes because the merge does not normalize or remix them for perceptual consistency.

Technical Details:

Each accepted file is decoded into floating-point pulse-code modulation (PCM) through the browser's audio decoder. The requested decoding rate is 44,100 Hz. Samples remain in their original order, silent zero-valued frames are inserted between clips, and the complete sequence is encoded as 16-bit PCM in a RIFF/WAVE container.

Formula Core:

Gap length is rounded to a whole sample frame. Total frames combine every decoded clip with the repeated gap, and duration divides that count by the output sample rate.

\begin{array}{rcl} F_{gap} & = & round (g \times r) \\ F_{total} & = & \sum_{i = 1}^{n} F_{i} + (n - 1) F_{gap} \\ T_{total} & = & \frac{F_{total}}{r} \end{array}

Here g is the gap in seconds, r is the output sample rate, n is the number of clips, and F_i is each decoded clip's frame count. At 44,100 Hz, a 0.5-second gap becomes 22,050 frames. Two clips lasting 12 and 8 seconds therefore produce a 20.5-second timeline.

Transformation Core:

Audio merge transformation stages
Stage	Transformation	Important consequence
Inspect	Check filename type, size, recognizable audio signature, and browser decoder support.	An accepted extension alone does not guarantee decoding.
Decode	Convert each source to one or two floating-point PCM channels at the audio context's sample rate.	The source codec, metadata, and original sample representation are not preserved.
Align channels	Use the largest channel count in the set; copy a mono channel into both sides when the output is stereo.	No loudness normalization or stereo remapping is applied.
Concatenate	Copy complete clip frames in order and insert zero-valued gap frames between them.	No overlap, crossfade, trimming, or effect processing occurs.
Encode and verify	Clamp samples to the PCM range, write 16-bit little-endian WAV, decode it again, and compare channels and frame count.	Preview and download use the verified local artifact.

The WAV stores a 44-byte RIFF header followed by interleaved signed 16-bit samples. Positive values scale to 32,767 and negative values to 32,768 before little-endian storage.

Privacy and Quality Notes:

Selected recordings are decoded, joined, verified, previewed, and encoded in the browser tab; they are not uploaded for audio processing.

Browser decoder support varies by source format and codec.
The output is PCM WAV, so compressed inputs usually produce a larger file and lose their original metadata.
Only mono and stereo sources are accepted; surround audio must be remixed before merging.
Keep an untouched copy and listen through the full result before publishing or replacing source files.

References:

Web Audio API, World Wide Web Consortium, 2021.
Resource Interchange File Format (RIFF), Microsoft Learn.