Testing for cabinet sizes for speakers without specs

Alongside my PC speaker enclosure project, another pair of PC speakers has since fallen into my hands froma circuit-blown speaker. I also have the afore mentioned Radio Shack Realistic 40-1011 for which specifications such as a Q of 0.4 is available on the manufacturers website.

The question I have is what sort of enclosure to build for each of these speakers, using them as full range speakers? It has been said that the larger the better, however I do not want to build a large one and then find out it does not sound good. I do not have access to the specifications of these speakers either except the one mentioned.

Could anyone comment on the method for experimentally finding a good cabinet size by the following methods:

1. Install the speaker in a large corrugated cardboard box and test.
2. Mount the speaker on a baffle and place it on a large wooden box, cupboard or drawyer, sealing the rest of the opening with cardboard or wood.

I am really down to experimenting with cabinet sizes since I cannot figure out the optimum size. How does a cabinet produce bass? Does the low freq sound come from the resonance of the cabinet walls?
Yes this is something I am exploring in my other thread "how speakers work..." . Things are becoming clearer.

Lack of a cabinet does not mean that there is no sound from the speaker, the sound, especially bass, is reduced, hence the open baffle concept.

Here's a link to using the rear walls in an open baffle concept to create a better sound.

Anyone tried mock-ups of various cabinet sizes for speaker drivers? One approach is to build a cabinet with moveable sides for testing and arriving at the optimum volume.