The couple was taking revenge on their new neighbors in the Stockholm area, who they said were too loud, Aftonbladet Daily reported Sunday.
The 71-year-old woman, whose name was not reported, said the new neighbors were so loud, she had to take sleeping pills in order to sleep.
"We wanted to give a taste of their own medicine," her 81-year-old husband said.
The couple set up a music system on their balcony facing their neighbor's home, police said.
The elderly couple allegedly played the music until as late as 4 a.m. throughout the winter, The Local.se reported.
"The harassment has just carried on, I am completely broken down. How can I keep living here," the neighbors told police.