Acoustic Voice after Update of avast!

Since a few days the acoustic voice after actuating with avast! update on my PC is missing. The blue windows after updating of avast! appears but without noice. The other speaker possibilities like Windows, CD, DVD, .wmv,.avi, .pps andso on are OK.
What can I do?

You can change the sounds: Right click the ‘a’ blue icon > Program settings > Sounds > Settings. Browse to avast set of sounds. Will it help?

Click the picture to enlarge

And so? Did you solve your problem?