i had a 4 way amp installed with 4 kenwood 6x9's. i was wondering if i could add a sub to it or what i would have to do. i am clueless about any off this

 

Simplest solution is a powered sub but a better solution is another amp and sub.

 

How much thump are you looking for? Listen to rap and need the big bang then go with another amp and sub woofer. Just want to add some base to round out the sound then go with a powered sub. These units are small enough to mount under the passenger seat and add a good amount of base. I just ordered one from crutchfield and hope to get it installed this weekend.

 

ya i just want some base i can hear. i dont need anything thats gonna shatter my windows

 

I would not run a sub off a amp that currently has mids and highs running off it. You dont want your sub putting out anything but bass.

Your options are like they said. a powered sub or add a second amp, and sub. I personally have never liked powered subs. but then again its been 15+years since ive used one.

 

so i think i am gonna do a powered sub. i read a bunch of reviews and it sounds like something i want. is it hard to hook them up or should i bring it somewhere and have it done for me?

 

I think you'll be satisfied with a powered sub.
AS far as ibstalling it, depends on your skill level. You'll have to tap into speaker wires and wire up power and grounds. Most likely you'll want it under the passenger side seat so you'll have to take that out to mount it. It's not a huge deal if you've done this kind of stuff before but if you haven't you might want to find a friend who has or have it professionally installed. I'll be doing mine but I've ripped apart plenty of cars for installs so it doesn't bother me.