Trimmer to substitute router?

[cersepn]

I'm new to wood working and would like to start out on my first set of DIY speakers. But i live in a really small apartment where space is a premium, so getting a router is quite out of the question.

Can a trimmer be a decent enough substitute? For cutting simple circle holes, flush trimming etc. Nothing too heavy duty. I did some reading around and it seems like it will do for most simple jobs. So my next question is, what can a router do that a trimmer cant?

[THORNSPAWN]

Trimmers work fine I use one occasionally, just use a small bit, 1/4in works well and don't try to cut too deep all at once.