A fast-food restaurant said it has seen a decrease in anti-social behaviour from customers, since it started playing classical music.
McDonald's in Welwyn Garden City had been identified as a disorderly behaviour "hotspot" by police, as first reported in the Welwyn Hatfield Times.
The restaurant turns off its wi-fi at 15:00 and plays "calming" music from 17:00 in an attempt to deter rowdiness.
Police said the measure "seemed to be working".
A Hertfordshire Police spokeswoman said the idea came out of an anti-crime strategy meeting.
A spokeswoman for McDonald's said: "We have tested the effects of classical music and played it in some of our restaurants as it encourages more acceptable behaviour."
Hertfordshire Police said its Operation Brillo aims to tackling anti-social behaviour in Welwyn "hotspots" including McDonald's, Woodall Shops and Peartree.
The force said the type of incidents include "rowdy behaviour and using offensive language, which tend to happen in the late afternoon and early evening".
People have been stopped and searched, letters sent to parents and home visits carried out.
McDonald's said it had also implemented its own measures, including banning a "small number of people" and improving the definition of its CCTV.
"[We] will continue to ask anyone causing a disturbance to leave the premises," the spokeswoman said.
"We are working very closely with the local council and police.
"We are pleased that since introducing these extra security measures we have seen a decrease in anti-social behaviour in and around the restaurant."