I Need some Advice on Speakers????
 

I have a 2002 Nissan Sentra GXE. It comes factory with two front door speakers and two rear deck speakers. I am currently replacing them. I have a pair of Polk Audio db651
6-1/2" / 6-3/4" 2-way Speakers (also Marine Certified) on the way that I am going to install in the front doors. My question is should I just get another pair of these to install in the rear deck or should I get a pair of mid bass drivers to put in the rear deck? Also since the back doors doesn't come factory with speakers in them would I be able to fit some speakers in them if so what size and if I can should I just then put two way coaxial s in the back doors or mid bass drivers or what? Please shoot me some Idea's and opinions.

A lot of people on here will suggest you skip the back speakers altogether and put some power to the fronts.

If you do decide to put in back speakers, keeping them the same, or at least the same brand, as the front is a good idea.

I have to replace the speakers in the back do to their age anyways just like I am in the front. So that is why I ask if I should either put Polk Db 651 pair in the back just like I am in the front doors or should I go with a Mid bass driver instead? Which do you believe will sound better?

If you have plans to add a subwoofer in trunk later, then forget the rear deck and rear doors, and buy a decent 2 way 6.5 component set for the front doors. The mid woofer would go in the front doors and you will have to find a mounting location for the tweeters, should fit in the sail pannel (little triangle on the upper front of the door body).

If you are not going the above route then the plok 6.5 you have should work in the front doors and add some good 6.5 for the rear deck that would give you more bottom end and you should be fine, no need to mod the rear doors.

I woulkd go with the first option.

I agree with the others on the forum, save your money and add a sub down the road (if thats what you want). Forget the rears.

According to Crutchfield, the '02 Sentra had a trim level that had a Rockford Fosgate 6 speaker system - with two tweeters mounted on the A-pillars.
If you were to go with a component set, it might be easy to place aftermarket tweeters where the factory installed tweeters may have went in the RF system.
If you're set on replacing the rear deck speakers, then there are some relatively inexpensive mid-bass drivers that would work. My quick search shows that the lower frequency for most of the drivers is only as low as 100Hz, but most are up around the 120-130Hz range.
I'd suggest these for the rear. Cadence CVL64MBX They have a lower frequency of 90Hz, and a 99dB @ 1w/1m sensitivity. The sensitivity may come into play if you're only sending them the signal from the head unit - as these speakers will be able to do more, with less power. Then, if you decide to amplify your system, these can handle a good deal of power.
If, at some point, you'd like to add a sub, then you'd just have to match an amplifier's output with the RMS of the Polk speakers (which is 60W). You could probably get away with a 5 channel amp that does 60-75W x4, and 250-350W on the subwoofer channel.

Boston Acoustics GTA-1105 5-channel car amplifier — 70 watts RMS x 4 at 4 ohms + 400 watts RMS at 2 ohms at Crutchfield.com, or something similar.

Thanks for the imput. 2002 Nissan Sentra GXE model without pillar pod speakers is what I have. It came stock with only two front coaxial door speakers and two rear deck speakers. No tweeters in the pillar's it would have been nice if my model came with it but it didn't.

I wonder how difficult it would be to find the OEM tweeter pod part, and pop them into your car... Could be a matter of talking to the dealership, or finding a Sentra with that stereo system at the junkers? The only thing you'd have to be mindful of is the size of tweeter that that mount would hold.
But as you have the Polk ordered already, its kind of a moot point, unless you're willing to change course now.

How large is the budget you have in mind? What are you currently using for the source unit?