How big of speakers can I put in my doors?

Hey guys I have a 1989 mazda b2200 and I was wanting to put new speakers in it. I already have 2 10" jl subs behind my seats but that's solid bass. I was looking for some door speakers. Does anyone know how large of speakers fit in the doors? 6"? Also do I need to do any kind of modifying or build a bracket for them? Thank you all!

I am researching this now, I haven't done it yet but here is what I have found:

Speaker depth is the concern, not so much size.

As for size, if you have manual windows make sure you can operate the hand crank without hitting your hand on the speakers, I read somewhere someone mounted the speakers too close to the window crank and that was an issue.

You may want to remove the door panel and measure depth and consider the depth of the speakers you wish to purchase to see how thick a mounting plate you need to install between the speaker and the door panel to clear the window. That is my next move, but when I do it I am converting to power windows and door locks, going to tear into the door all at once...

Let me just state that I've seen many door panels at the parts yard that were damaged by speaker installations....

I am running 6"s in my doors, they fit good and don't hit the window crank. Do you have anything installed in the pillar where your seat belt is? I upgraded mine and it made a huge difference. But as Cusser said, you can ruin a door panel if you aren't careful. Spacers help a lot.

I would build a speaker mount for it. Out of fiberglass and you can paint them or wrap them in any material. That way they are spaced out about 1-2 inches (depending on how thick you make them) from the door and you can fit 5 1/4'' to 6'' speakers if you want. Some do one speaker and other with do two right next to each other. Fiberglass is easy to work with too. Here's a couple of threads that will help ya out.

For spacers I have used MDF or hardboard. Making it the same size as the speaker and the grill hides it. Paint it to blend in.
My first mazda had 6's in the doors but they were removed and the door panel had to be re-wrapped. I had 4" separates with the 4 in the stock dash location and the tweeter on the door in the upper corner opposite the outside mirror. I had JL 10's behind the seat. It was an 87 single cab. Everything was ran off an alpine amp and it was loud.

If you are going to make something with fiberglass you could do a kick panel if you have the floor corner space. Kick panels can work awesome because the speakers are pointed towards you for the best sound. I have them in one of my civics and The sounds great. The downside is getting shoes rested on them. If you have a body drop and tubs. There isn't much space for one.