EBU R 128 s1 is the EBU’s supplement for short-form content such as commercials, promos, interstitials and bumpers. It keeps the -23 LUFS programme loudness and -1 dBTP true-peak ceiling of R 128, adds a cap on maximum short-term loudness of -18 LUFS, and drops loudness range as a target. WavSpec includes an EBU R 128 s1 short-form preset, so you can check and correct a batch of spots on Windows and send a report with them.
Short-form is where loudness complaints start. A 30-second spot can hit -23 LUFS integrated and still have a few seconds that jump out of the break. The supplement exists to stop that.
Check a folder of spots against R 128 s1 and see the short-term peaks per file.
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What is EBU R 128 s1?
R 128 is the EBU’s loudness recommendation for broadcast; the current version is R 128 v5.0, published November 2023. Supplement 1, EBU R 128 s1, Loudness Parameters for Short-form Content, adds rules for programmes that are too short for an integrated measurement alone to describe how loud they feel. The version we checked is the 2020 edition, which added tolerances for quality control and true peak.
The supplement defines short-form content as a programme of short duration, up to approximately 2 minutes and typically shorter than 30 seconds: advertisements, promos, interstitials, stingers, bumpers and similar very short items.
What are the R 128 s1 numbers?
| Parameter | R 128 s1 value | Tolerance or note |
|---|---|---|
| Programme loudness | -23.0 LUFS | Plus or minus 0.2 LU for quality control |
| Maximum short-term loudness | -18.0 LUFS, which is +5 LU above target | Tolerance of +0.2 LU |
| Maximum true peak | -1 dBTP | Measurement tolerance noted as plus or minus 0.3 dB |
| Loudness range | Not applicable to short-form content | No LRA target |
| What to measure | The whole signal | No emphasis on speech, music or effects alone |
Values are from EBU R 128 s1 (2020 edition), tech.ebu.ch/docs/r/r128s1.pdf, checked on 17 October 2026. Always confirm against the broadcaster’s own delivery spec, which may tighten these values.
Two things stand out compared with long-form R 128:
- A QC tolerance. For quality control workflows, s1 allows plus or minus 0.2 LU around -23.0 LUFS to account for measurement error. That is a tight window, so a spot at -22.6 LUFS should be treated as a fail.
- A short-term ceiling. The 3-second short-term loudness must not go above -18 LUFS. That is the rule that catches a spot that is quiet overall and loud in the punchline.
Why does maximum short-term loudness matter more than LRA?
Loudness range is a statistical analysis of the 3-second short-term loudness values. The supplement explains that a commercial or promo leaves too few data points for a meaningful result, so no maximum or minimum LRA is specified for content of this length.
What viewers notice in a break is a burst. If the voiceover is loud and the music bed underneath is quiet, the integrated value can sit at -23 LUFS while the voiceover moments run several LU hotter. A short-term cap measures those bursts directly. Our guide to LUFS, LKFS, dBTP and LRA explains each measurement window.
Can gain alone fix a short-term overshoot?
Not usually. Gain moves integrated and short-term loudness by the same amount. If a spot measures -23.0 LUFS integrated and -16 LUFS maximum short-term, turning it down to meet -18 LUFS short-term puts the integrated value at about -25 LUFS, outside the 0.2 LU tolerance.
The fix is a mix decision: reduce the dynamic jump between the loud moment and the rest, by riding the voiceover, compressing the bed less, or changing the arrangement. That belongs in your DAW. A delivery tool’s job is to show you exactly which spots fail and by how much, so you know which mixes to reopen.
How do I check a batch of spots against R 128 s1?
WavSpec ships an EBU R 128 s1 short-form preset among its ten built-in specs, each cited to its source document. It measures integrated, short-term and momentary loudness, loudness range and 4x oversampled true peak per ITU-R BS.1770-5.
- Add the spots. Drag in the folder of finished spots. WavSpec reads WAV, BWF, RF64, AIFF, FLAC, MP3, AAC, M4A and WMA, in mono, stereo, 5.1 and 7.1.
- Choose EBU R 128 s1 short-form. Set the delivery folder.
- Check. Each spot is judged against each criterion, with the measured and required values side by side, and a short-term loudness timeline that shows where any overshoot sits.
- Correct what gain and limiting can correct. WavSpec sets gain to the exact target and applies look-ahead true-peak limiting only where the gain pushed peaks over. A spot whose short-term overshoot needs a remix still shows as a fail, so it is never quietly passed.
- Send the report. The report in PDF, HTML, CSV and JSON lists before and after values per criterion, the cited spec, a batch consistency line, your client and project details, and the SHA-256 of every delivered file.
Find the spots with short-term overshoot before the broadcaster does, in the 15-day free trial.
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What about ATSC A/85 and other short-form rules?
North American spots are normally delivered to ATSC A/85 at -24 LKFS. WavSpec’s ATSC A/85 (2026) preset covers full-mix and short-form; see our ATSC A/85 loudness check page. Some European broadcasters publish their own specs on top of R 128, and WavSpec includes UK DPP AS-11 and ARD/ZDF/ORF TV (2025) presets as well. For a broadcaster not on the list, duplicate a preset and set its target, tolerance, peak ceiling and optional short-term, momentary and loudness-range limits.
When is a different tool the better pick?
- You are mixing the spot. Use a real-time loudness meter in your DAW while you mix. WavSpec checks finished files; it does not show live levels as you play.
- You only deliver one spot a month. A free meter plugin that shows short-term loudness may be all you need.
- You need a Mac. WavSpec runs on Windows 11 version 22H2 or later, x64 only.
Frequently asked questions
Is EBU R 128 s1 the same as R 128?
No. It is a supplement that applies the R 128 programme loudness and true-peak values to short-form content and adds a maximum short-term loudness rule. LRA is not applicable to short-form content under s1.
What is the maximum short-term loudness in R 128 s1?
-18.0 LUFS, which is 5 LU above the -23 LUFS target, with a tolerance of +0.2 LU in quality control workflows, per the 2020 edition of the supplement.
Does WavSpec fix a spot that fails the short-term limit?
It sets gain and limits true peaks, then re-measures. If the short-term overshoot can only be fixed by changing the mix, the spot stays marked as a fail with the measured values, so you know to reopen it.
Can I add a broadcaster’s own short-form spec?
Yes. Duplicate the R 128 s1 preset or choose New, set the values from the broadcaster’s document, and export the spec as a file to share with colleagues.
Does WavSpec send files anywhere?
No. It opens no network connection, has no account and collects no telemetry.
Try WavSpec
WavSpec is a one-time purchase in the Microsoft Store, with a 15-day free trial. Run last week’s spots against the R 128 s1 preset and read the short-term timeline for each. For long-form broadcast delivery, see normalize audio to EBU R 128, or visit the WavSpec product page.
Deliver short-form spots to R 128 s1 with the numbers to prove it.
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EBU is a trademark of the European Broadcasting Union. Microsoft and Windows are trademarks of the Microsoft group of companies. Other names are trademarks of their owners. WavSpec is not affiliated with or endorsed by any of them.
Last updated 17 October 2026. Published by Automata Labs, a software company in Canada.