Sound Problems, Found information here https://help.ubuntu.com/community/HdaIntelSoundHowto that help me have have better sound quality.

1. Type below to find out what sound card you are using.

cat /proc/asound/card0/codec#* | grep Codec

Dell Precision T3400 uses a Codec: Analog Devices AD1984

2. View this file /usr/share/doc/alsa-base/driver/ALSA-Configuration.txt.gz and search for AD1984, 
You should see that the T3400 there is a dell option.

3. Edit sudo gedit /etc/modprobe.d/alsa-base.conf and at the bottom put with out quotes,
"options snd-hda-intel model=dell"

4. Reboot

That should be it. I found that the sound seemed to be better after adding this option.