The Need for Bass

I have recently installed 4 new aftermarket speakers in my car:

- Two 6" 3-way Boss Audio speakers with 10mm tweeter (at the rear)
- Two 4" 2-way JVC speakers with 10mm tweeter (at front)

I know these aren't high profile speakers as I am on a budget being a University student and all. At the moment the front speakers aren't blocked by a grille, therefore the sound bounces around freely from the front which provides quite good, clear sound with some respectable bass for 4" 2-ways.

At the rear, however, I have a plank of wood whereby the speakers are concealed underneath. If I were to cut holes where the speakers are on the plank of wood, would the bass improve? I heard a rumour when speakers are blocked, the quality of the bass actually decreases.

As I stated, I'm on a budget and really don't want to fork out a couple of hundred dollars on a 200W+ subwoofer and 1000W+ amp.

any sound wave will not sound accurate if it is playing into a solid face of wood. the wave will bounce of and go in all directions.