Other than pulling the door panel and measuring them, you can go to the Crutchfield website (http://www.crutchfield.com/). Enter the appropriate information about your car and they will give you all the relevant info.
4x6 are the size of the door speakers on 2004 GMC Sierra. Standard cab
The front door speakers in a 2004 Volkswagen Polo measure 6.7 inches. This is equal to about 170 mm or 17 cm.
Front Door Speakers are 6-1/2"
6X8"
Answer The front door speakers are 4x6 inch and the rear deck speakers are 6x9 inch in a 2004 Grand Am.
6 3/4 oversize 6.5 in the front door
i believe all sunfire door speakers are 5 1/4" but with a mounting bracket, it can accommodate a 6 1/2" speaker, depending on the mounting depth.
The front speakers I know are 4x6's despite two door or four and I am pretty sure the rear are 6x9's
Rear ones in the back dash are 6x9, front ones in the door panels are 4x6.
there is screws around the door panel and the right under the handle there is 2 of them then your door is off hope this helps you :)
Front door I believe are 6x9's
I'd really like to know