Volume louder than a pneumatic drill was recorded at Ashford cinema which has led to a plea for film sound to be turned down once a week.
A survey by Hearbase Ltd, which has an audiology clinic at the QEQM hospital, Margate, revealed that films are being shown with peak levels louder than a rock concert.
The survey was carried out as part of Deaf Awareness Week which runs from Monday to May 11.
Cinemas in Ashford, Canterbury, Thanet, Dover and Folkestone were tested on March 26.
Five people watched the film 10,000 BC at the same time while wearing a data recording device to record noise levels.
The results showed Ashford accumulated a peak average at 123dB - the highest of all the cinemas.
The other measurements were: Canterbury (113dB), Dover (122.8dB), Folkestone (117.2dB) and Thanet (117.8dB).
Peaks of more than 125dB were recorded which is above the pain threshold and louder than a pneumatic drill. A loud rock concert is around 115dB.
Hearbase director Mark Scutchings said: “These results are scary and are proof that our cinemas are showing films at dangerous volumes.
"All the cinemas tested recorded levels above 100dB consistently and most were frequently above the 115dB level expected at a rock concert.
“We are urging cinemas to inform their customers about the risks and offer cinemagoers the choice of a quieter performance.
“Showings for children should also be quieter, as there is particular concern about the risks of hearing damage and young people.”