Acoustic glass consists of at least two panes bonded by one or more polyvinyl butyral interlayers. These interlayers dampen vibrations and interrupt sound transmission. The key to its performance is an asymmetric build-up: different glass thicknesses prevent both panes from resonating at the same frequencies. Sound reduction indices from Rw 42 dB to over 50 dB are achievable. Combined with a suitable window frame and continuous seals, defined sound insulation classes can be met. Applications include apartments near busy roads, airports, or commercial zones. Proper embedding in the outer frame is essential to avoid structure-borne sound bridges that would compromise overall performance.