I have a Hp Pavilion dv5 laptop and was having sound problems. I have Linuxmint 7 64 bit, which is based on Jaunty Jackalope (Ubuntu 9.04)

I found this article at https://help.ubuntu.com/community/SoundTroubleshooting which can also help you with HP dv models.

The latest alsa-driver snapshot provides a fix for this issue.

Get it here and do below:

cd ~
mkdir src
cd src
mkdir alsa
cd alsa
wget ftp://ftp.kernel.org/pub/linux/kernel/people/tiwai/snapshot/alsa-driver-snapshot.tar.gz
tar -xvpf alsa-driver-snapshot.tar.gz
cd alsa-driver
./configure
sudo make
sudo make install-modules

Edit this file
sudo gedit /etc/modprobe.d/alsa-base.conf

and add this entry at the bottom "options snd_hda_intel model=hp-dv5" without the quotes.