Front speaker installation? 2001 tahoe

Has anyone replaced their speakers? Do I have to take the door panel off or can I go through the speaker grill? Also are the door speakers the only ones in the front or are there some up under the dash. Any help would be great.

Thanks

I did just this, and the back doors. Yes you do have to take off the panels to access the speakers. I put 6 1/2" mids with 1" Highs and 6" coaxils in the rear doors. Beware, the stock stereo has a stock amp that runs to all the speakers.
I don't believe that there are any under the dash.