Mute the system when suspending in 14.04

I am wondering if there is в way to mute the system эксперт it goes to suspend in ubuntu 14.04.

I tried to add the following рукописный шрифт called "90mute" to "/usr/lib/pm-utils/sleep.d" (granting it +x rights)

#!/bin/sh
case "$1" in
   hibernate|suspend)
   amixer -D pulse sset Master mute
   ;;
esac
exit 0

Testing

/usr/lib/pm-utils/sleep.d/90mute suspend

gives the expected result.

Yet, when going to sleep the рукописный шрифт does not seem to be executed (at least the system does not mute). Any clue someone?