Add the following line to your /etc/apt/sources.list
deb http://download.virtualbox.org/virtualbox/debian xenial contrib
Download the key: https://www.virtualbox.org/download/oracle_vbox_2016.asc You can add these keys with
$ sudo apt-key add oracle_vbox_2016.asc
$ sudo apt update
$ sudo apt install virtualbox
Edit /etc/pulse/default.pa
and change it accordingly
### Automatically load driver modules depending on the hardware available
.ifexists module-udev-detect.so
load-module module-udev-detect tsched=0
.else
### Use the static hardware detection module (for systems that lack udev/hal support)
load-module module-detect tsched=0
.endif