Weird how it works from the Live session.
First, open a terminal and run this...
sudo alsactl init
Second, try opening pavucontrol (S+v), go to the Output tab and make sure it's not muted. Even if this fixes it, you might find that you have to keep opening pavucontol.
If that's the case, I would uninstall pulseaudio (easily re-installed) and see if alsa "just works"...
sudo apt-get purge pulseaudio pavucontrol && sudo apt-get install alsa-base
OK, re: my OP question, I see that libreoffice also has been backported. If I run apt-cache policy libreoffice-writer it shows the candidate as being from jessie (I'm running the alpha ISO here so writer was not installed by default)...
hhh@64bit:~$ apt-cache policy libreoffice-writer libreoffice-writer: Installed: (none) Candidate: 1:4.3.3-2+deb8u1 Version table: 1:5.0.1-2~bpo8+1 0 100 http://ftp.us.debian.org/debian/ jessie-backports/main amd64 Packages 1:4.3.3-2+deb8u1 0 500 http://ftp.us.debian.org/debian/ jessie/main amd64 Packages 500 http://security.debian.org/ jessie/updates/main amd64 Packages
So can I assume that pk-update-icon was offered from the backports without targeting it because there is no version available from the stable jessie channel?
The lack of an update notification systray icon in BL bothers me, and I noticed that pk-update-icon is now available in jessie backports. So I enabled the source, updated and mistakenly entered apt-get install without '-t backports' and apt is ready to install pk-icon-update. But it shouldn't, I should have to specifically target backports. Can anyone else reproduce this, and do you know what's going on?