Ditch normal speakers for audio exciters
We all know that most laptop speakers are not the best, bass is often lacking, mids are weak and they sound rather "tinny".
Since laptops have a very limited space, large speakers are not a option. But there is hope. The "exciter" is a speaker like no other. Instead of using a cone to produce sound, it sticks to a flat surface and vibrates the surface. These speakers are very thin, small and light weight.
So, you could install 2 small tweeters, then install a pair of these "exciters" into the LCD case, or the palm rest, or even the bottom cover. Thus turning the whole laptop chassis into the speaker.
Here is a company that sells them, they also have specs and info on them.