Hello!
I noticed a little issue with the latest version of avast! antivirus free, that occurred since the last software update.
I enabled avast! sound and, after every definition’s update, I hear a double “DONG!” instead a single one. I mean “DONG-DONG!”. It seems strange. It is a new sound, or what?
Regards, Alpha.
Not a new sound, seems to be a little bug at some OS.
There are some Threads about this in the forum.
In the german part of this forum we call it “ping-ping”, but your “Dong-Dong” is very nice, too! 
;D
Oh, I have Win XP SP3 (updated), avast! Free (7.0.1456), Comodo Firewall (antivirus and defense+ modules disabled, only firewall running).
Just for the sake of report.
Thank you.
I also have Windows XP SP3 with all updates and mine also give the double audio notice
when Avast does it’s definitions updates. It too started when 1456 came out. Not a real
pesky issue, but it should be fixed in an update (I hope)
I’m sure, it will!
First the double sound was in W2k too, but now it’s ok! 
I think, the guys from avast!-team fixed it and they will do this for XP, too!
Just turned on my computer and got the double audio message, defination update. My computer is Win XP, sp3, updated, (my dell desktop.)
Hoping this is fixed soon. Thank you.
I run free avast 7.0.1456
Strange I had never had it until the 120724-0 virus definitions update, not something that I was too bothered with though. On my win XP Pro system but not on my win7 netbook.
For those that are experiencing this is it happening on every auto update ?
Hi David,
W2000 & XP: No, not on every auto update. It changes nearly every day in different forms.
We have a special Thread for this little bug in the german part of the forum:
I can confirm it in Windows 8 64 bit Release Preview!
I have just had an auto update (I had been off-line for a few hours) and in honesty I can’t recall if there was a double notification, shows how much attention I pay to it. To me it is just background chatter when I’m working. Still not had this on my win7 netbook.
I saw this with today’s first update on this win7 laptop
Still not seeing/hearing it on my win7 netbook.
This double update notification started on my system a few days ago. Running version 7.0.1456 on a Dell with Windows 7 Home OS.
This has been going on for me for about 4 days on Win 7 Pro 64 Bit. I get the sound and then a few seconds later I get the sound and pop up. The Streaming updates may just be out of sink. I do not know but I hope this is fixed soon. It also appears that I am only getting one update a day.
I’ve been hearing the double message on EVERY definition update on my WIN7 netbook (same system as you) now for about 2 weeks, it’s interesting that some have the problem and some do not under otherwise similar circumstances (I’m using FREE Avast).
That’s the problem, the inconsistency of it, at first the people reporting it were using winXP, so many though it was restricted to XP. But then others started to report it when using other OSes so that it is more widespread, but not effecting everyone. This must make it harder to track the cause and or interaction and come up with a fix.