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ST Processors · Audiobook Suite
Every file. One loudness. Accepted.
Batch-correct your whole audiobook to the delivery standard — −18 LUFS with a −3 dB true-peak ceiling — the loudness spec distribution platforms expect. Just correction, done properly: no mastering, no surprises, and files already on target come back untouched.
Free 20-minute preview after sign-up. No card needed.
Loudness correction — 14 files
measured → corrected, per file
chapter-01.wav−24.6 LUFS
chapter-02.wav−14.1 LUFS
chapter-03.wav−21.9 LUFS
after correction
all 14 files−18.0 LUFS
true peak≤ −3.0 dBTP
−18 LUFSintegrated, every file
−3 dBTPtrue-peak ceiling — no clipping
Whole bookone batch, all chapters
Untouchedfiles already on target pass through unchanged
How it works
Correction, not mastering
If a platform bounced your files for loudness — or your chapters were exported at different levels over weeks of sessions — this brings every file to the same accepted standard. Nothing else about your audio is changed.
1
Upload your book
Every chapter at once — WAV, AIFF, MP3, FLAC, M4A, AAC, OGG or OPUS.
2
Each file is measured
Integrated loudness and true peak, per file. Files already at −18 LUFS with peaks under −3 dB are returned exactly as uploaded — not re-encoded, not touched.
3
Corrected & verified
Everything else is corrected to −18 LUFS with a −3 dB true-peak ceiling, re-measured to prove it landed, and delivered back file by file.
The audiobook standard
−18 LUFS / −3 dBTP — the delivery loudness audiobook platforms and publishers ask for.
Level only — by design
No EQ, no compression character, no "enhancement". Your narration sounds like your narration, at the right level.
Consistency across chapters
Chapters exported months apart land at one identical loudness — the thing listeners (and reviewers) notice most.
Be aware: loudness up = noise up
Turning a quiet recording up turns its room noise up with it. Loudness correction cannot — and honestly, should not pretend to — clean a noisy recording: if your noise floor is borderline, correcting the level can push it over a platform’s limit. Not sure where you stand? Run our free compliance report first — it measures your noise floor on every file before you spend a penny.
Need the full platform rulebook checked — room tone, bitrate, noise floor? That’s the ACX Compliance Check.
Using more than one tool? ST Suite pools one set of hours across every processor — plans from £49/month, annual with two months free.
Good to know
Frequently asked
No — deliberately. It corrects level: integrated loudness to −18 LUFS and true peaks under −3 dB. There’s no EQ, no compression flavour, no processing personality. If you want your audio to sound different rather than just measure right, that’s a mastering conversation.
No, and be wary of anything that claims to do both in one pass. Raising loudness raises the noise floor with it. If your recording is borderline hissy, check it first with the free compliance report — it measures the noise floor of every file so you know before you correct.
−18 LUFS with a −3 dB true-peak ceiling is the standard delivery loudness for audiobooks — it’s what distribution platforms and publishers typically specify, and it sits inside ACX’s required range for typical narration. For a strict ACX submission, run the full compliance check too: ACX also measures room tone, bitrate, noise floor and more.
Only files that need correcting are processed, and the output preserves your format spec. Files already on target are returned byte-for-byte identical — the tool proves they pass and hands them straight back.
Your finished chapter files — WAV, AIFF, MP3, FLAC, M4A, AAC, OGG or OPUS. Whole book in one batch; everything stays in your private account area.
One level. Every chapter.
Upload the book, download it at −18 LUFS — verified file by file.
Create your free account
Your first 20 minutes are corrected free — no card needed.
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