I didn’t find a compelling reason to have pulseaudio instead of ALSA as a default sound system on my ubuntu “Lenny” (with GNOME). Instead, being unable within 15 minutes to fix sound for firefox / flash plugin, I’ve decided to go back to well known (for me at least) ALSA, which turned out to be a next 45 minutes exercise. What I did after all is:

  1. Change /etc/asound.conf to
    pcm.!default {
    type hw
    card 0
    }
    ctl.!default {
    type hw
    card 0
    }
  2. remove all pulseaudio-related packages
    sudo apt-get remove libasound2-plugins “pulseaudio-*” paman padevchooser paprefs pavucontrol pavumeter
  3. restart sound system /etc/init.d/alsa-utils restart
  4. restart Firefox.

The number of the card (0 in my case) can be found this way:

dimonf@x41:~$ cat /proc/asound/cards
0 [ICH6           ]: ICH4 – Intel ICH6
Intel ICH6 with AD1981B at irq 23

That’s it.