Dialplan - variable for the path to the sound files

Hello, everyone,
is there a variable I can use in my dialplan to refer to the absolute path to the location of the sound files? I need to use it when I want to check for file existence. Or must I specify it every time as /var/lib/asterisk/sound?

${ASTDATADIR} should be the variable you want for where on disk asterisk has it’s sounds.

Thank you for help. I will try it.