Audio Spectrum Analyzer runs the audio editing and conversion job locally inside your browser. Drop in any audio file to see a frequency spectrum analysis. Identifies which frequencies are present and at what energy level — useful for diagnosing tone problems, finding noise, and learning what your audio "looks like" in the frequency domain. The work happens on your machine, the result is generated on your machine, and the page exposes the controls you need to drive it without burying them in menus.
Behind the controls you see, standard browser APIs is doing the actual audio editing and conversion. MP3, WAV, M4A, AAC, OGG, Opus, FLAC, AIFF, and WMA are first-class formats and the engine produces a deterministic output for any given input + options combination — useful when you need to re-run a job and expect identical results.
Audio Spectrum Analyzer parses your file with standard browser APIs entirely inside the browser, applies the options you selected, and returns a download. The processing has no network step, which means a slow or intermittent connection does not slow down the work — once the page is loaded, only your CPU and RAM are involved.
Anyone who works with audio editing and conversion on a casual basis — language learners reviewing speech, students preparing oral submissions, streamers cleaning microphone tracks — finds Audio Spectrum Analyzer a quick way to get the result. The page loads in under a second, the controls are visible from a single screen, and the result downloads or copies in one click.
The right moment to reach for Audio Spectrum Analyzer is when you have a focused audio editing and conversion job that fits inside a browser tab. Open the page, drop in the file or paste your input, choose the options that matter, and the tool returns the result.
The architecture imposes only the limits the browser itself imposes. The published 200 MB ceiling is conservative; most modern devices comfortably handle inputs up to that size, and the cap exists so the tool degrades gracefully on phones and budget laptops rather than running out of memory.
Audio Spectrum Analyzer fits naturally next to several adjacent tools. Common companions include Audio Frequency Analyzer, Audio Waveform Visualizer, Audio Equalizer, and Audio BPM Detector — combine them when the job needs more than one transformation. After running Audio Spectrum Analyzer, many users move on to Audio Frequency Analyzer and Audio Equalizer. Each tool is a separate page so you can compose the exact pipeline you need.
Audio Spectrum Analyzer is built around steady iteration on a small set of options rather than feature creep. Every additional setting attracts a slightly different audience, but a long settings panel makes the common case slower for everyone. The current controls reflect what users of the tool actually use.
Audio Spectrum Analyzer returns the result as `{name}-edited.{ext}`. If you are running multiple jobs, the output names will not collide as long as the input names differ. You can re-run with different settings as many times as you like; each run produces a fresh file with no caching trickery in between.
Some context on why Audio Spectrum Analyzer exists in this form: modern File APIs, high-performance JavaScript engines, and well-maintained open-source libraries now make it possible to perform audio editing and conversion work entirely in the browser. Audio Spectrum Analyzer is built on top of that capability, which is why a single page can host the full pipeline.
As a single-page tool, Audio Spectrum Analyzer stays focused on one audio editing and conversion step. Multi-step workflows are composed by chaining adjacent tools — each tool produces a standard file the next one can read directly, so a longer pipeline is just a sequence of short tab-and-tab visits.
Pro tip: Audio Spectrum Analyzer works just as well in a private/incognito window as in a normal one, which is occasionally useful when you want zero browser-history footprint of the job. Another tip: if the tool ever feels slow, it is almost always because the browser tab is competing for CPU with another tab — pausing or closing the heavy ones gives the engine room to work.
If the result is not what you expected, the most common causes are easy to check. Confirm the input is under the 200 MB ceiling — files just above the cap fail silently because the engine refuses to allocate the buffer. Confirm the input is one of the supported formats. And if the page itself feels slow, try closing other heavy tabs to free up memory; the engine runs in your browser, so it competes for the same resources as everything else open.
Audio Spectrum Analyzer is intentionally narrow in scope so the common case is fast and the result is predictable. If you ever need a variation it does not cover, browse the rest of the catalog — there is a good chance an adjacent tool already exists, and switching between tools is just a matter of opening another tab.
The audio is decoded to PCM, then a Fast Fourier Transform (FFT) is computed to extract the energy at each frequency band. The result is plotted as energy (dB) vs frequency (Hz, log scale). The visualization shows the average frequency content of the entire file, similar to FFmpeg's `showspectrumpic` filter.
The frequency profile of your audio. A vocal recording shows energy mostly between 80 Hz and 8 kHz. Music has energy across the full 20 Hz – 20 kHz range. Hiss shows as a flat plateau in the high frequencies. Hum shows as a sharp peak at 50 or 60 Hz. Clipping shows as harmonics extending unnaturally far up.
Look for narrow peaks at unexpected frequencies — a peak at 60 Hz means AC hum, peaks every 60 Hz are AC harmonics. A broad bump in the 8–12 kHz region might be hiss or sibilance. After identifying problem frequencies, use the EQ tool to cut them.
Human hearing is logarithmic — the ratio between 100 Hz and 200 Hz feels the same as between 1000 Hz and 2000 Hz (both are one octave). Linear frequency display would make low frequencies look squashed and high frequencies dominate. Log scale matches how we actually hear pitch.
This Spectrum Analyzer shows the average frequency content of the whole file (great for diagnostics). The Frequency Analyzer focuses on instantaneous peak frequencies and their musical note mapping (great for tuning and pitch identification).
Up to 200MB. Decoding and FFT analysis happen in the browser; expect 1–5 seconds for typical files, longer for very long lossless files.
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.
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.
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.
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.
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.
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.
Your file is processed inside your browser by standard browser APIs. The engine reads the file's bytes from your tab's memory, computes the result, and writes the result back into the tab. You can confirm what the page does by opening developer tools and watching the Network tab during a run — the requests you see are for the tool's static assets only.
Once the page is loaded, Audio Spectrum Analyzer can complete jobs without an active internet connection — the engine is bundled with the page, so there is no per-job network call. The initial page load does require a connection (to fetch the static assets), but after that you can disconnect entirely and the tool will still work. This is a side-effect of the local-first architecture, not a deliberate "offline mode" feature.
Audio Spectrum Analyzer is built on standard browser APIs, which is the same class of engine used by professional audio editing and conversion pipelines. For deterministic operations, the output is byte-identical to what an equivalent CLI run would produce; for operations involving a codec or a model, the result is well within the range of what comparable tools generate. If you have a specific reference output you need to match, run a small test job first to confirm the configuration produces what you expect.
Audio Spectrum Analyzer is built to preserve quality wherever the underlying audio format allows it. Operations that are mathematically lossless (e.g. structural transformations, lossless re-encoding) round-trip with no perceptible change. Operations that involve a lossy codec inevitably introduce small artefacts at the byte level, but the defaults aim at the sweet spot where output looks or sounds the same to a normal viewer or listener while still being meaningfully smaller or faster than the input.
Audio Spectrum Analyzer runs in any modern mobile browser — Safari, Chrome, Firefox and the in-app browsers in most messaging apps all support the underlying APIs. Performance depends on the device: a recent phone handles typical inputs nearly as fast as a laptop, while older devices may take a few seconds longer near the 200 MB ceiling. The interface lays out cleanly on small screens, so you do not need to pinch-zoom to see the controls.
Audio Spectrum Analyzer 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.
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.
Audio Spectrum Analyzer is a browser-only tool by design and does not expose a hosted API. The reason is the same as the privacy story: there is no Favtoo backend doing the work, so there is no service to call. If you need to script the same transformation, the underlying engine (standard browser APIs) is open-source and can be used directly from your own code.
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.
Metronome
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.
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.