What's the 2004 honda civic sedan speaker size?

The front door speakers in a 2004 honda civic sedan are 6.5 Inches. The rear deck corners are 6 x 9 inches, and there are also tweeters on the front door.

Completely inaccurate for the lx sedan. Door has 525 openings with available expansion to a 6.5 speaker with an adapter bracket as long as the speaker does not have a large magnet because it will make contact with the window if it is. I would recommend infinity reference slim mount coaxials. They sound great even paired with the often underated stock stereo that is actually a decent sounding alpine. Kicker also fits both 5,25 and 6.5 as well as polk db6522. The rear opening fits a 5.25 speaker that is wired with a lp crossover so it plays quietly allowing the sound stage to remain upfront. Upgrade to a better full range speaker such as jbl club or an infinity reference but keep it wired with the stock configuration especially if you choose to not add an amp and you will be amazed how good it sounds with the oem deck that has the ability to play hi res flac files and through an adapter bluetooth and mp3 files. I know everyone will say replace the deck but it is not a weakness by any means in this cars audio setup especially paired with the before mentioned aftermarket speakers due to their hi sensitivity rating. This 93 db+ sensitivity allows them to work perfectly with this deck sounding as if they were indeed powered by an amp. I will add sound deadening is a must for the doors, This is a major weakness of this particular model. Un modified road noise is an issue and optimal sound from the doors is unattainable But with some modification using baffles and speaker foam as well as sound deadening to seal the door Guaranteed you wont have to break the bank to make your cars audio sound great. If you do amplify this car run new speaker wire because the stock wire does not match up well with the increase in wattage that comes from an aftermarket amplifier due its small gage which is in the 17 or 18 gage category.