Are you experiencing an intermittent popping sound from your speakers when nothing is playing? I encountered it after upgrading a PC with an HDA Intel audio controller to Xubuntu 9.10 Karmic Koala. It occurs 10 seconds after a sound stops playing because that’s when the audio chip is turned off to save power.

To prevent the popping noise, you just have to disable the power saving mode.

1. With your favorite editor, open /etc/modprobe.d/alsa-base.conf as root (Important: Run the editor using sudo or gksudo to give it root permission. You can’t save the file otherwise.)
2. Locate the line that reads, “# Power down HDA controllers after 10 idle seconds”
3. Immediately following that comment is the offending option:
   options snd-hda-intel power_save=10 power_save_controller=N
4. Insert a hash # character at the very beginning of the option line to turn it into a comment. It should look like the following:
   #options snd-hda-intel power_save=10 power_save_controller=N
5. Save the file and restart Ubuntu

If you have a different sound controller and are experiencing this noise, look in the file for a similar-looking option (e.g., options snd-hda-something power_save…) and comment it out. Share your experience in the comments.