I think i've solved it.
The script reporter in this page works fine: http://ubuntuforums.org/showthread.php?t=1475616&page=2
mv 50alsa 09alsa
I just forgot the first piece and i didn't rename the file.
case "$1" in
# Stopping is not required
/sbin/alsa force-reload > /dev/null
*) exit $NA
Anyway, the problem wasn't the audio but the bluetooth.
After the wake up from suspend, the bluetooth doesn't work. Since the audio was sent to the bluetooth output, there was no sound.
If i don't use the bluetooth output but only the internal speaker, the audio never fails, even without the script.
So i found this script for the bluetooth: http://ubuntuforums.org/showthread.php?t=1387211
sudo touch 10_bluetooth
It turns off the bluetooth before the standby and turns it on again after the wake up.
#Code from http://ubuntuforums.org/showthread.php?t=1387211
case "$1" in
rfkill block bluetooth
rfkill unblock bluetooth
The audio starts on the internal speakers and after some seconds goes to the bluetooth output.
Now the only problem i've left is that if i reboot i have to reconnect the bluetooth device. It is already connected-paired but it is not connected in "audio sink", and i have to do it manually every time.
Any advices about this?