There is another approach that may work. This is specific to the Dell Inspiron E1705/9400 model w/ STAC9200 codec.
Open this file for editing:
Insert this line at the bottom:
gksudo gedit /etc/modprobe.d/alsa-base.conf
Save. Close. Reboot. Check your levels in alsamixer.
options snd-hda-intel model=dell-m27
Press F6 to select the correct soundcard.
Press F3 to show playback levels. F4 selects capture levels [or use <Tab>]
Use the left/right arrow keys to select and up/down arrow keys to change levels.
Go to "System>Preferences>Sound" and make sure the correct soundcard is default