The loudness wars took off when digital domain compressors enabled look-ahead limiting analog gear could not achieve
The progressive escalation of average CD levels was enabled by digital domain compressors. Because they operate in the digital domain, they can look ahead in the circuit and achieve a theoretical zero attack time — doing things no analog gear could — letting engineers crank average loudness far higher. In vinyl there was a natural brake (too-loud records skipped and got returned); digital removed that physical limit, so levels kept climbing.
Examples
Bob Ludwig: ‘people started inventing these digital domain compressors where you could just start cranking the level up… you could look ahead in the circuit and have a theoretical zero attack time.‘
Assessment
What specific capability of digital domain compressors enabled loudness levels impossible with analog compressors?