"Dummy Output" sound in Ubuntu 14.04

I added my user to the 'audio' group and after re-logging in, it was fixed.

usermod -a -G audio $USER

I noticed when aplay wasn't able to list devices as a user:

Listing with with my account:

aplay -l  

aplay: device_list:268: no soundcards found

It didn't see any cards, but when listing with root (sudo):

aplay -l 

\*\*\*\* List of PLAYBACK Hardware Devices \*\*\*\*  
card 0: Intel [HDA Intel], device 0: ALC892 Analog [ALC892 Analog]   
Subdevices: 1/1    Subdevice #0: subdevice #0

it saw them all.

I don't know why this was necessary, because on my other machine the group exists, and my user isn't part of it either. It did work though.

I checked the sound card information you provided and this is what I came up with. According to what I found by searching the internet, you have to edit the alsa-base sound configuration file and add either dell-s14 or dell-vostro-3500 to it. Your Dell Inspiron laptop is not a Dell Vostro, but it is a Dell laptop. Since there are only two alternatives to choose from, choose dell-s14.

If that doesn't work, I suggest you try dell-vostro-3500 because Dell Inspiron and Dell Vostro are similar in many ways. The Dell Vostro is a business version of the Dell Inspiron consumer laptop with some differences in the hardware and specifications.

Before you run the following commands read them first, and if you have already tried them comment, as it will save you from doing unnecessary work.

Open the terminal and type:

sudo touch /etc/modprobe.d/alsa-base.conf.bak
sudo cp /etc/modprobe.d/alsa-base.conf /etc/modprobe.d/alsa-base.conf.bak  # backup alsa-base.conf
sudo nano /etc/modprobe.d/alsa-base.conf 

This will open alsa-base.conf for editing in nano text editor. Scroll down to the bottom of alsa-base.conf and add this new line to the bottom:

options snd-hda-intel model=dell-s14

Press the keyboard combination Ctrl+O and after that press Enter to save the changes you made to alsa-base.conf. Press the keyboard combination Ctrl+X to exit nano.

Next run the following command:

sudo alsa force-reload  

The next time you reboot check to find out if the changes you made held up after a reboot.

sudo modprobe snd-hda-intel

This command uses modprobe, a tool for adding and removing modules from the Linux Kernel, to add support for the audio.