Most audio tools do one thing. These do it well — and they run entirely in your browser, no sign-up, no install.
1. Audio Beat Matcher — Sync Any Track to Any Tempo
Got a track at 128 BPM that needs to sit at 125? Audio Beat Matcher calculates the tempo ratio and applies FFmpeg’s atempo filter to stretch the audio without changing pitch. Leave the source BPM blank and it auto-detects using MusicTempo — just drop a file and hit process.
Best for: DJs building playlists, producers matching loops, video editors syncing music to action.
2. Audio Silence Detector — Find Every Gap in Your Recording
Silence isn’t always silence. This tool uses FFmpeg’s silencedetect to precisely locate every gap — configurable by threshold (dB) and minimum duration. Output is clean JSON with start/end timestamps and total silence duration.
Best for: Podcast editors trimming dead air, audiobook producers fixing awkward pauses, DJ set organizers cleaning intros.
3. Audio Loudness Normalize (LUFS) — Broadcast-Ready in One Click
Spotify normalizes to -14 LUFS, YouTube to -14 LUFS, podcast platforms often target -16. Audio Loudness Normalize wraps FFmpeg’s loudnorm filter with three key controls: Integrated Loudness (I), True Peak (TP), and Loudness Range (LRA). Set your target, drop your file, get a file that passes loudness specs.
Best for: Podcasters, streamers, and anyone distributing audio across platforms with different loudness requirements.
Try Audio Loudness Normalize →
4. Audio Dialog Isolation — Pull Vocals from Any Track
This is the tool that would have taken a plugin and a manual. Feed it any audio file and choose between Spleeter or Demucs/MDX separation engines. It outputs a ZIP containing two files: the vocal stem and the instrumental/accompaniment stem, ready for remixing, karaoke tracks, or analysis.
Best for: Remix producers, language learners isolating speech, journalists cleaning interview audio.
5. Audio Binauralizer — Give Stereo Real Depth
Stereo widening adds width. Binauralization adds space. The Audio Binauralizer offers two modes: Pseudo 3D (using stereo widening and phase manipulation) and HRTF (with a SOFA file for physically-based head-related transfer functions). Adjust stereo width and phase shift in Pseudo 3D mode — or go full HRTF for immersive headphone experiences.
Best for: Game audio engineers, ambient music producers, ASMR creators building spatial audio.
6. Audio Stem Mixer — Three Mixes, One Upload
Got stems? Audio Stem Mixer takes up to 8 audio files, designates one as the vocal, and produces three mixes: a flat normal, a vocal-up version (+3 dB by default), and a vocal-down version (-3 dB). All three come in a single ZIP. It handles format conversion and applies a limiter to prevent clipping on the vocal-up mix.
Best for: Mix engineers comparing balance, karaoke makers, DJs who need instrumental and acapella versions.
7. Audio Preview Snippets — Preview Audio Without Playing the Whole Thing
Labels, curators, and DJs often need to preview long tracks. Audio Preview Snippets extracts evenly-spaced clips (configurable 5–10 seconds each, 2–8 snippets) from across the full duration. Output is a ZIP of individual clips, ready to share or batch review.
Best for: Music supervisors screening catalogs, podcasters creating episode teasers, students reviewing lecture recordings.
Why These Tools Work Together
Audio production has a pipeline: you match tempo, clean silence, normalize loudness, isolate dialog or stems, add spatial processing, compare mixes, and generate preview clips. Most tools handle one step. These seven cover the full workflow — and they do it in your browser, free, without an account.
The missing piece? None of these require a subscription or a powerful machine. FFmpeg runs the processing on the server side, and the browser handles the interface. That’s it.
One Thing You Can’t Do Yet
These tools work on finished or recorded audio — they don’t generate music from scratch, and they don’t master to a specific commercial standard automatically. You still need human ears for the final say. But for everything before that final listen? You have what you need.
