01
Drop the file
WAV, MP3, AAC, FLAC or OGG, up to 1 GB — or tap to choose one on a phone. Several at once if you want to compare a master with its MP3.
Free LUFS meter · A Squaresmile app
Is it too loud? Drop the file and know.
LoudSense shows what Spotify, YouTube, Apple Podcasts or the broadcaster will do with your file: peak, true peak, clips, LUFS and loudness range on a waveform, a verdict per platform with the fix in dB — and one click to fix it. The audio never leaves your device.
Free — no account, no signup
Nothing uploaded — audio never leaves your device
ITU-R BS.1770 / EBU R128, true peak, LRA
How it works
Ten seconds from file to verdict.
02
It is measured on your device
The browser decodes the file and measures as it goes. WAV, and MP3 in browsers that can stream it, cost the same memory for two hours as for a jingle. The audio is not sent anywhere.
03
Read the verdict
Pick Podcast, Music, Audiobook, Broadcast or Live concert. Every row says OK, too loud, too quiet, peaks too hot or clipped — and by how many dB. Underneath: the waveform with clip marks, peak marks and the loudness curve.
04
Fix it
Press Fix to this on a row and LoudSense writes a WAV at that target, measured again until it lands. Or copy the report for the client.
Features
Everything the platform will measure, before you upload.
True peak, not just peak
Sample peak says −0.2. True peak, oversampled, says +0.4. The second one is what the encoder and the platform see. LoudSense shows both.
Every clip, marked
Runs of full-scale samples are counted and drawn on the waveform. A clipped file gets its own verdict, because turning it down does not bring the cut-off peaks back — you need the master before the clip.
Verdict per platform
Spotify, Apple Music, YouTube, Amazon Music, Tidal, Deezer, Apple Podcasts, ACX, EBU R128, ATSC A/85. Streaming rows say what the service does ("turned down by 2.3 dB"); broadcast rows say it straight: out of spec — would be rejected.
Loudness over time
The momentary-loudness curve over the waveform shows where an episode drifts and where a song's chorus lands, not just one number for the whole file.
Fix it, and preview the encoder
One click writes a WAV at the target with a true-peak limiter, re-measured until it lands within 0.1 LU; for MP3 or AAC delivery the ceiling drops to leave room for the encoder. Encode preview shows what the encoder does to your peaks — before you upload.
Private by design
No upload: the audio is decoded and measured on your device. What stays is a short history of numbers in this browser — file name, loudness, date — which you can clear. Your unreleased single or client episode stays on your machine.
Beyond the numbers
Built for the weekly episode and the album master.
Speech or music?
A strip under the waveform marks where the file is voice and where it is music, with an estimated loudness for each — so you know whether the music sections sit 4 dB over the voice before the listener does.
Episode history
Every file you check is remembered in this browser — file name and numbers, never the audio. The next episode of the same series shows a trend line and warns when episodes drift more than 2 LU apart.
Level-matched A/B
Play two files in sync and flip between them, matched in loudness — compare the sound, not the volume. Or hear one file at the level Spotify or Apple would play it, turned down or up. On iPhone and iPad too.
Whole folders, 5.1 too
Drop an album, a playlist or a season: up to 100 files analyse in name order, land in one compare table and give you the album loudness. A 5.1 mix is measured on every channel, the way the broadcaster measures it.
Your own targets
A station spec, a client's house rule, a club's playback level: add it once with tolerance and ceiling, get a verdict row like any platform, and it follows you to the next device with a free account.
Charts, CSV and the share sheet
A loudness histogram and the short-term curve with the LRA band, the curve as CSV, the panel as PNG — and on Android with the app installed, LoudSense appears in the share sheet: the recording waits until you tap Analyse.
In the tool
Waveform, numbers, verdict.
In your DAW — in preparation
The same meter as a plugin and a desktop app.
LoudSense is coming as a VST3 and AU plugin for the master bus and a standalone app for files, built on the same measurement core as this page: a file will read the same in the browser, in the plugin and in the app.
The whole song, not one pass
Play any part, in any order: every part lands on its place in the song, and the newest pass over a part replaces the old one. The verdict covers everything measured so far, with a bar showing what is covered and how fresh it is. An offline bounce fills the whole song in seconds.
Capture and compare passes
Press Capture, or let play and stop do it for you. The panel you know from here, inside the DAW, with the last five passes side by side, so before and after a limiter change is one glance.
The fix, not just the number
Pick Spotify or Apple Podcasts and the bars show the window, the true-peak bar its ceiling. Every verdict says what to do: turn down by 1.6 dB, or put a true-peak limiter at −1 dBTP when turning down would leave the window.
Sections and markers
Drop markers while capturing or import the DAW's marker list. Verse, chorus and ad read each get their own LUFS-I, true peak and clip count.
Watch folder and batch reports
Point the app at the bounce folder and every export is measured as it lands; a bounce that misses the target raises a notification. Or drop an album: one table, a CSV or HTML report with the verdict per platform and the album loudness.
Dialogue loudness, estimated
An estimate of the speech-only loudness next to the full mix — the kind of value long-form TV and streaming deliveries specify. It is labelled an estimate: those deliveries are measured with the broadcaster's own dialogue detector. Plus history, shareable target files and playback at a platform's level.
In preparation — no price yet. Planned for macOS (Apple Silicon and Intel) and Windows. Write to support@squaresmile.de to hear when it ships, or read the plugin guide.
FAQ
Quick answers.
Is my file uploaded?
No. LoudSense decodes and measures the audio in your browser; the audio never goes to a server. What stays behind is a short history in this browser — file name, loudness, peaks and date, no audio — so the next episode can be compared with the last. Clear it any time. Your own targets are the one thing that syncs with your Squaresmile account.
What does LoudSense measure?
Sample peak, true peak (oversampled), clips, momentary, short-term and integrated loudness in LUFS per ITU-R BS.1770, and loudness range per EBU Tech 3342. Mono, stereo and multichannel files are measured as BS.1770 says: a 5.1 file counts every channel, with the surround channels weighted and the LFE left out. The test suite runs the EBU reference signals: integrated and short-term loudness within ±0.1 LU (EBU Tech 3341), loudness range within the Tech 3342 tolerance.
Why does my MP3 clip when the WAV master did not?
Lossy encoding rebuilds the waveform, and the rebuilt peaks overshoot. On a loud master limited to −1 dBTP we measured +1.7 to +2.8 dBTP after a 128 kbps MP3 encode and up to +1.4 dBTP after 256 kbps AAC — 2.4 to almost 4 dB of overshoot. Quieter, more dynamic material overshoots less. Check the encoded file, not only the master: Encode preview shows it before you upload, and Fix it lowers the ceiling when you deliver MP3 or AAC.
How long a file can it handle?
Up to 1 GB. WAV streams in every browser, MP3 in browsers whose WebCodecs can decode MP3 (Chrome and Edge, for example), so memory stays flat even for a three-hour recording. Everything else — AAC, FLAC, OGG, AIFF, and MP3 where streaming is not available — goes through the browser's own decoder in one piece: up to 250 MB on a laptop and 60 MB on a phone.
Does it fix the file?
For loudness, yes. Fix it applies the gain and a true-peak limiter, measures the result and corrects it until it lands within 0.1 LU of the target with the true peak under the ceiling, then downloads a WAV; the original is untouched. For MP3 or AAC delivery it lowers the ceiling to leave room for the encoder. It is a normaliser, not a mastering chain: no EQ, no compression. A clipped master stays clipped — the cut-off peaks cannot be restored — and noise, phase and DC still need your editor.
Does it work on a phone?
Yes. On a phone the verdict comes first and the waveform below it, and every verdict row has its own Fix to this button. On Android, with the app installed, you can share a recording straight to LoudSense; it opens when you tap Analyse.
Which platforms does it check against?
Music: Spotify, Apple Music, YouTube, Amazon Music, Tidal and Deezer, plus SoundCloud and Bandcamp, which play files as uploaded. Podcast: Apple Podcasts and the common −19 to −16 LUFS podcast convention. Audiobook: Audible/ACX. Broadcast: EBU R128, R128 s1 for ads and trailers, and ATSC A/85. Live concert: −14 LUFS for a recording that goes to streaming or release (a convention — no standard exists for concert recordings) and the ±1 LU live window of EBU R128 for TV. Add your own target for a station spec, a client rule or a playback level.
Is LoudSense free?
Yes, and checking files needs no account: open LoudSense and drop a file. A free Squaresmile account adds your own targets on every device and unlocks every other Squaresmile browser tool. The desktop plugin is in preparation and has no price yet.
Ready when you are
Check it before the platform does.
Open it and drop a file — no account, no signup. A free Squaresmile account adds your own targets on every device and unlocks every other Squaresmile app.
