Since I've seen so many topics about issues with the sound of vortex II here I thought I'd post my 5 cents related to the issue.
I personally own a Vortex II 15" so my experience to differences with the 17" model is limited. The 17" model has a toggle for "enhanced audio", which is FN+5. I haven't heard the difference myself so it's hard to describe what it does. The most plausible explanation that I found was that it would toggle the THX program on/off.
After I got the laptop I installed a clean installation of Windows 7 Ultimate. Then I installed all the drivers included on the CD that came with the laptop. It is important to install both the realtek drivers and the THX Trustudio Pro. I also noticed that the sound was a bit silent at the beginning so I started to look into it - nowadays I rarely raise my volume above 50%. A word of warning - while the laptop does okay in terms of movies and games, you just won't get the same kind of audio experience even by trying out the settings in this guide as you would get from your Ipod.
When using the laptops speakers, it is essential to make sure you have set the speaker configuration to either 5.1 or 7.1 in realtek control panel. This depends on your own personal taste on which sound image you like better out of the two. You can also turn off rear speakers after making this change as they are not really present (17" version has them) but after testing, the signal that would go to rear speakers is guided to the front ones.
THX panel is where the tweaking is done.
Surround: This is pretty self explanatory, but reducing the value can boost your laptop speaker volume. However, my advice is to toy with it and pick a level where you like the sound
Crystalizer: Boosts bass and treble.
Speaker: This one makes rather little difference, my personal opinion is to leave it at the default level.
Smart Volume: This one should be maxed to boost overall volume.
Dialog Plus: Boosts vocal range in music and movies, tune to your preference. Can also be left off if you don't think you need it.
Smart Volume is the main thing here, maxing it will boost the volume quite a bit. This is pretty much all that is necessary to tweak the performance of the laptop speakers.
The main reason for the poor performance of headphones I've found to be is that when you plug them in THX recognizes them as "external speakers". The fix is to go to the THX Trustudio panel again and to open the drop down menu and pick options. It will show three devices and you should pick the option "headphones", this will make all the difference in the world. The sound image will be completely different. When you do do this, you also get to the option to change "crossover frequency". This means that you can select the frequency point where the audio output to your headphones is split into two - low and high frequencies. Try out this option to find you perfect settings. I am looking into why headphones aren't automatically recognized or why there isn't a popup to pick which type of device was plugged in.
Hopefully this will help people struggling with the audio issues. The guide itself is very much a work in progress right now.
*** Last Update 13/03/12 ****