Offline loudness lab for audio delivery

Loudgrain

Measure ITU-R BS.1770 / EBU R128 loudness and true peak on device, build a batch of measurements, and plan the gain to hit Apple Music, Spotify, YouTube, and broadcast targets before you deliver — without ever changing your source audio.

iPhone + iPadOn-device onlyAudio never modifiedNo account, no tracking

From file to measurement

Measure the loudness, then plan the gain

Loudgrain decodes each file locally, reports the BS.1770 metrics, and matches the measurement to a delivery target. The illustrations below show the concept model; the app renders your own files and results.

MEASUREMENT album_master.wav · 48 kHz · BS.1770 K-weighted INTEGRATED-16.4LUFS MOMENTARY-12.1LUFS SHORT-TERM-14.9LUFS LOUDNESS RANGE6.2LU TRUE PEAK · 4× OVERSAMPLED-1.3dBTPceiling headroom GATED INTEGRATION · -70 LUFS ABSOLUTE + -10 LU RELATIVE GATE amber = integrated loudness · warm = true-peak estimate · every value from your file
Illustration: each measurement reports integrated loudness, momentary and short-term loudness, loudness range, and a 4x-oversampled true-peak estimate.
TARGET PLAN Spotify · -14.0 LUFS · ceiling -1.0 dBTP -14.0 LUFS target short-term loudness over time GAIN TO TARGET +2.4 dB PEAK-SAFE GAIN (keeps peak ≤ ceiling) +0.3 dB
Illustration: read the short-term curve against your chosen target and see both the gain to the integrated target and the peak-safe gain that holds the true peak under the ceiling.

What Loudgrain does

A focused loudness workspace

Every value comes from the audio you add. Loudgrain measures and plans; it does not master, normalize, or re-encode your files, and it does not connect to any service.

Real BS.1770 measurement

K-weighting and gated integration report integrated loudness (LUFS), momentary and short-term loudness, and loudness range (LRA), with a true-peak estimate from 4x oversampling.

Build a batch

Add WAV, AIFF, CAF, or M4A files, or start from the bundled sample, and keep a batch of measurements to compare albums, podcasts, stems, and deliverables side by side.

Plan for every target

Match a measurement to Apple Music, Spotify, YouTube, EBU R128, ATSC A/85, and podcast targets, with the gain to reach the integrated target and a peak-safe gain that respects the true-peak ceiling.

See the curve

Read a short-term loudness curve against your chosen target, with clear metric tiles for every measurement so you can judge the whole delivery at a glance.

Export a report

Export a plain-text loudness report through the system share sheet and choose where it goes. Your source audio is never modified and never uploaded.

Premium by design

The paid download includes the full tool. There is no account, subscription, in-app purchase, advertising, analytics, tracking, or server dependency. Everything runs on device.

Delivery targets

Plan against the standard you deliver to

Loudgrain ships with the common integrated-loudness targets and true-peak ceilings. It shows the gain to reach each one from your measurement; you decide what to apply in your own mastering chain.

Apple Music-16 LUFS-1 dBTP
Spotify-14 LUFS-1 dBTP
YouTube-14 LUFS-1 dBTP
EBU R128-23 LUFS-1 dBTP
ATSC A/85-24 LUFS-2 dBTP
Podcast (AES)-16 LUFS-1 dBTP

Read this first

A measurement and planning aid, not a certified compliance meter

Loudgrain is a measurement and planning aid. Its loudness and true-peak values are estimates produced on your device and are not a certified compliance measurement.

Verify regulated broadcast or mastering deliverables with calibrated, validated tools and the applicable delivery specification before you ship. The bundled target presets are provided for convenience and are not a substitute for each platform's current published requirements.