Effective sound isolation requires airtight construction, which conflicts with ventilation needs.

Evidence

So in order to have good sound isolation, one needs good partitions and an airtight, draught-free structure. Achieving this in practice while still allowing the occupants to breathe is a challenge. — David M. Howard, Jamie Angus, Acoustics and Psychoacoustics, 2127

Categorization

• XREF: Connects to the silencing/quiet-space theme: engineered quiet (sealed rooms, anechoic chambers) always trades off against liveability. — connects to: In homes, air leaks dominate sound isolation more than the glazing itself — David Howard, Jamie Angus, coustics and Psychoacoustics, 2173
• SEED: Essay angle: the design paradox of quiet — why every attempt at acoustic isolation runs into the ventilation problem, from double glazing to anechoic chambers.