Technical & Engineering
ATSC A/85
The North American technical equivalent to R128, utilized by the Advanced Television Systems Committee to regulate broadcast loudness.
What is ATSC A/85?
ATSC A/85 is the North American loudness recommendation that accomplishes what R128 does for Europe. It also uses LUFS-based measurement (specifically the BS.1770 algorithm underneath both R128 and A/85) and sets a target loudness — -24 LKFS — for North American broadcast. The two standards are engineered to be technically interoperable, so content conforming to one is trivially adjustable to the other.
A/85 is enforced in the United States by the CALM Act (Commercial Advertisement Loudness Mitigation Act), passed in 2010. That law made A/85 compliance legally mandatory for US broadcasters, with fines for violations. The CALM Act is why US television commercials no longer seem jarringly louder than the programmes around them — a real-world consumer improvement driven directly by a technical standard.
Why it matters
Serves as the stringent technical foundation for the CALM Act, mandating strict legal compliance and heavy fines for commercial loudness violations in the US.
Related terms
- EBU R128— The standardized loudness recommendation instituted by the European Broadcasting Union (EBU) to strictly normalize audio levels across platforms.
- RDS (Radio Data System)— A standardized communications protocol used for embedding small amounts of digital information into conventional analog FM radio broadcasts.
- A-D Converter— Analog-to-Digital Converter; specialized hardware that translates continuous analog electrical signals into binary digital data (1s and 0s).
- Actuality (Sound Bite)— Unfiltered, raw audio recordings captured on location outside the controlled studio, featuring interviews or ambient background sound.