Does Double glazed glass provide good acoustic insulation?

Its a common myth that insulated glass provides a good acoustic shield. This is NOT COMPLETLY TRUE. In fact a 6mm+12mm air
gap +6mm insulated glass provides less acoustic insulation than a 12mm monolithic glass at most frequencies. Laminated glass on the other
hand provides far superior acoustic insulation when compared to insulated glass; as much as 5-12dB extra-protection over low frequency
range, which is the traffic-zone. In order to use DGU for sound insulation the ideal air gap should be more than 40mm