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About Metronome

Metronome is the kind of utility you bookmark and reach for when you need it. A precise browser-based metronome powered by the Web Audio API. Set BPM from 30 to 300, choose a time signature, accent the first beat, and use tap-tempo to sync. Click timing is sample-accurate using lookahead scheduling — much steadier than typical JavaScript setInterval beats. It loads quickly, works on any modern browser, and produces a result you can download or copy in a single click.

Metronome sees the most use from musicians sharing demos and podcasters preparing episodes, but the design is intentionally generic enough that you do not need a specialist background to get a good result. The defaults aim at the most common case so a first-time user can get the right output without changing any settings.

Reach for Metronome when you need a predictable result on a single file. The page works on the first visit, the controls are visible without a menu, and the output is delivered the moment the engine finishes.

Metronome runs on standard browser APIs — an open-source, well-audited engine that performs the audio editing and conversion natively in the browser. It accepts MP3, WAV, M4A, AAC, OGG, Opus, FLAC, AIFF, and WMA and produces output that opens in any standard audio viewer. Per-run input is capped at 200 MB.

Because everything runs in the page, the tool scales the same way for one user or a million — there is no per-user backend cost. The page is static, the engine is the same JavaScript bundle for every visitor, and the work happens on the visitor's own device. That keeps the tool free and keeps it fast on the first interaction.

Once you have used Metronome, the natural next steps depend on what you are doing with the result. Common follow-ups include Audio Trimmer, Audio Clip Maker, and Audio Speed Changer. These are surfaced on the page so you do not have to hunt the catalog manually.

The only practical limit is the 200 MB per-file ceiling, which keeps the tool responsive across a wide range of devices. Run the tool ten times in a row, run it ten thousand times — it behaves the same way and produces the same quality of result.

Some notes on the design of Metronome. The page is intentionally narrow: one input, the controls relevant to the task, and one output. Adding unrelated features would make the common case slower for the majority of users, so the surface is held to what people actually use.

When the job finishes, Metronome hands you the result as `{name}-edited.{ext}`. Filenames are derived from your input where possible, so a quick batch of jobs leaves you with a tidy folder rather than a pile of generic "output (3)" files. Nothing is auto-saved on Favtoo's side because nothing was ever sent there.

Metronome is structured around the idea that a useful tool should be its own page. Open the page, do the work, close the tab — the page is the entire product. There is no onboarding flow because there is nothing to onboard into.

Metronome runs as a regular web page, so there is no install step or permission grant before the first run. The page can be audited by viewing the source or by watching the developer-tools Network tab while a job runs.

If you want to get the most out of Metronome, three small habits help. Drag-and-drop is faster than the file picker once you get used to it. The keyboard shortcut for downloading the result is whatever your browser uses for "save link as," because the result is a normal download. And if you are working on a sensitive file, processing in an Incognito or Private window is a good extra layer — it leaves no trace in browser history when the tab closes.

If Metronome appears to hang, the engine is almost certainly still working — large inputs simply take longer to process inside a browser than they would on a server with multi-core scheduling. For inputs near the 200 MB cap, give it up to a minute on a typical laptop before assuming something is stuck.

If Metronome solved your problem, sharing the page link with someone who has the same problem is the most useful thing you can do. The catalog grows mostly through word of mouth; visitors arriving through a recommendation tend to be the ones the tool serves best.

How it works

  1. 1Open Metronome in your browser. The page loads quickly and the tool is ready to use the moment it becomes interactive.
  2. 2Select the MP3, WAV, M4A, AAC, OGG, Opus, FLAC, AIFF, and WMA file you want to process — drag-and-drop and the file picker both work.
  3. 3Tweak the controls if the defaults are not quite right for your input. The options are kept short and labelled in plain language.
  4. 4Trigger processing. standard browser APIs reads your input, applies the transformation, and writes the result back into the page.
  5. 5Download the result as `{name}-edited.{ext}`. The file is generated in your browser and saved through your normal download flow.
  6. 6Re-run with different settings as often as you want. Each run produces a fresh output and the original file on disk is never modified.

Common use cases

FAQ

How accurate is this browser metronome?

Very accurate. The clicks are scheduled ahead of time using the Web Audio API's scheduleAtTime, which is sample-accurate (sub-millisecond precision). This is dramatically better than scheduling clicks with setTimeout or setInterval, which drift and stutter under load. Even at 240 BPM with another tab playing video, the click stays steady.

How does tap tempo work?

Tap the Tap Tempo button (or the spacebar) at least twice in rhythm — the tool averages the intervals between your taps to derive BPM. The more taps you give it (4–8 is ideal), the more accurate the result. Tap tempo is great for matching the BPM of a song you are listening to without having to count.

What time signatures are supported?

2/4, 3/4, 4/4, 5/4, 6/8, 7/8, and 9/8 are built-in. The first beat of each measure is accented with a higher-pitched click, while subsequent beats use a lower pitch. This makes it easy to feel the downbeat in odd meters like 7/8.

Why does the click sound a bit different from a wooden metronome?

We use a short pure-tone click (1 kHz for the accent, 750 Hz for normal beats) generated by an oscillator with a fast envelope. This is more cutting and easier to hear when practicing with an instrument than a wooden block sound. There is no audio file involved — every click is synthesized fresh.

Can I use it for live performance?

Yes — it stays running as long as the tab is open. For critical performance use we still recommend a hardware click track or a dedicated performance app, only because browsers can pause background tabs to save battery. Keep this tab in the foreground.

Why is in-browser audio sometimes slightly delayed?

Bluetooth headphones add 150–300ms of latency, which is the killer for any metronome. Use wired headphones or speakers for tight timing. The metronome itself is rock-solid; the delay is in the wireless audio chain.

Why is in-browser audio processing slower than online tools?

Server-side tools use multi-threaded native FFmpeg running on dedicated CPUs with fast disks and parallel pipelines. Our engine is FFmpeg compiled to WebAssembly, which runs single-threaded inside your browser tab and has no access to native hardware acceleration. That makes browser-based jobs typically 3–8× slower than a server. The trade-off is total privacy: your audio file is never uploaded, never logged, and never stored — closing the tab erases everything from memory immediately. For most clips up to a few minutes the wait is small, and for sensitive recordings (voice memos, drafts, confidential meetings) the privacy gain is well worth it.

Is my audio uploaded?

No. Everything runs entirely inside your browser tab using FFmpeg compiled to WebAssembly. The file is read into local memory only, processed in the same tab, and the result is offered as a direct download. Nothing is transmitted to any server, no account is required, no analytics are tied to your file, and closing the tab discards every byte from memory.

How big a file can I process?

The file picker accepts audio inputs up to about 1 GB, which is well above what mainstream "free tier" online converters allow. The real ceiling is your device — everything runs inside your browser tab, which shares memory with the rest of the page. Most podcasts, songs, and voice memos sit comfortably under that limit even on a phone. If a very large lossless WAV or FLAC ever fails, trim it first or transcode to MP3 / Opus to bring the size down before re-running the tool.

Which audio formats are supported?

MP3, WAV, OGG (Vorbis and Opus), FLAC, M4A (AAC), AAC, Opus, AIFF, and WMA all decode reliably via FFmpeg WASM. Output formats depend on the specific tool — most editing tools default to MP3 (universal) or WAV (lossless) but expose a format picker so you can pick the one that fits your downstream player or DAW.

Which browsers are supported?

Recent Chrome, Edge, Firefox, Safari, and other Chromium-based browsers all work. The tool relies on WebAssembly and SharedArrayBuffer, which require the page to be served over HTTPS with the right cross-origin headers — this site is configured correctly by default. On phones the same code runs but is slower than on a desktop because mobile CPUs are weaker.

Is there a watermark, sign-up wall, or usage cap?

No. The tool is completely free, requires no account, attaches no watermark, applies no usage caps, and shows no popup ads on your output. Because the work happens on your own device, there is no per-user quota for us to enforce — your hardware and browser memory are the only limits. The download is the file you would get from running FFmpeg locally, nothing more, nothing less.

Can I use Metronome for commercial work?

Metronome can be used for personal and commercial work alike — there is no separate "business" licence to purchase. The output you generate is yours to use however you want, including in client deliverables, internal documents, or commercial products. Favtoo's only ask is fair, individual use; the tool is not designed to be embedded as a backend service or wrapped behind an API for resale.

Does Metronome require a browser extension or plug-in?

No installation is needed. Metronome runs as a normal web page, with no browser extension, no native helper, and no separate desktop client to download. That is partly a privacy choice — extensions can request broad permissions, while a regular page is sandboxed by default — and partly a convenience one: you can use Metronome on any computer you have temporary access to without leaving anything installed on it.

What should I do if Metronome fails on my file?

Failures usually fall into one of three buckets: the input is in an unsupported format, the input is over the size cap, or the input is structurally malformed (a truncated download, a partial export, or a stream the engine does not recognise). The first two are easy to confirm — check that your file is one of MP3, WAV, M4A, AAC, OGG, Opus, FLAC, AIFF, and WMA and that it is below 200 MB. For the third, opening the file in its native viewer first is the fastest way to confirm the source is intact.

Which file formats does Metronome accept?

Metronome accepts MP3, WAV, M4A, AAC, OGG, Opus, FLAC, AIFF, and WMA. If your input is in a format that is not directly supported, convert it first using one of Favtoo's converter tools — every Favtoo converter outputs a file that is a clean input to the next tool in the chain.

Is Metronome keyboard accessible?

Metronome uses native HTML controls wherever possible, which means keyboard navigation, focus rings, and screen-reader labels work the way the platform expects. The drop zone accepts files via the keyboard-accessible file picker as well as drag-and-drop, and result downloads use standard browser download flows. If you spot an accessibility gap, Favtoo treats it as a bug worth fixing.

Can I process multiple files at once with Metronome?

Metronome processes one input at a time by design — it keeps memory usage predictable on lower-end devices and makes results easier to verify. To handle a folder, run the tool once per file; the page stays loaded between runs and remembers your last-used settings, so the second run is essentially instant.

Will Metronome ask me to pay to download the result?

Metronome is free to use. The processing runs in your browser, which keeps the per-user cost low enough that the tool can be offered openly. The download is the same file the engine produced — you can use it for as many runs as you need.

Will Metronome keep working in a year?

Metronome is updated whenever the underlying engine releases an improvement or a bug fix. Because the tool is delivered as a static page, every visit fetches the latest version automatically — there is no "version" to manage on your end. If a particular release ever changes default behaviour, the change is documented on Favtoo's changelog so you can confirm what shifted.

Audio Recorder

Record from your microphone directly in the browser. Pick quality (high, medium, low), toggle echo cancellation, noise suppression and auto-gain, then save to WebM/Opus or M4A/AAC. Audio is captured locally — nothing is uploaded.

Text to Speech

Type or paste text, pick a system voice, and listen instantly. Adjust speaking rate (0.5×–2×), pitch, and volume in real time. Uses your browser's built-in Web Speech API — no cloud TTS, no API keys, no costs.

Tone Generator

Generate a pure tone at any frequency from 20 Hz to 20 kHz. Pick a sine, square, triangle, or sawtooth waveform, choose duration, amplitude, and mono/stereo. Exports a 16-bit PCM WAV file at 44.1 kHz with built-in click-preventing fades.

Silence Generator

Generate a perfectly silent WAV file of any length from 1 second up to 1 hour. Pick mono or stereo, get a 16-bit PCM WAV at 44.1 kHz. Useful as padding between clips, intro silence, leader audio for video timing, or test material.

White Noise Generator

Generate white, pink, or brown noise as a 16-bit PCM WAV file. Pick noise type, duration up to 1 hour, amplitude, and mono/stereo. Useful for sleep, focus, masking distractions, audio testing, and as a backing layer for ambient music.

Audio Trimmer

Trim any audio file to a precise start and end time. Outputs a lossless stream-copy by default (no quality loss, very fast) or re-encodes to MP3, WAV, OGG, or M4A. Files are processed entirely in your browser with FFmpeg WebAssembly.

Audio Splitter

Split a long audio file into N equal-length parts and download them as a ZIP. Each part is named sequentially. Great for chapterizing audiobooks, podcasts, or long DJ mixes. Runs entirely in your browser with FFmpeg WebAssembly.

Audio Merger

Merge up to 12 audio files into one continuous track. Supports MP3, WAV, OGG, M4A, AAC, FLAC, Opus, AIFF and more. Optional loudness normalization to even out clip levels. Files are processed entirely in your browser with FFmpeg WebAssembly.

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