I have two 10 inch subwoofer in a very big box. 4.4 cubic feet before displacement. I have one 4 inch Aero I made with pvc pipe but I get noise at low notes,tuning right now is 30hz. Was thinking to go with 6 inch tuned to 33hz.

First thing I'd do is make your box smaller.  Fill it with something.  

 

At the same time, describe the noise you are hearing please.

The noise sounds like alot of air is trying to get through the port but can't properly, that's the best way I can describe it, only occurs at high volume and on really low notes. I plan on putting maybe 4 8 inch in the box or 2 12 and I don't have the time to make another one right now.

First step is to fix the overall size of the box and then re-listen.  Bit of a catch 22 though as you won't know what you need for port length until your volume is right since they are related.

 

No matter a 4" is too small so you need to go bigger.  Pretty easy to model and find out how big

Thanks so much for your help. Will change port and maybe put some bigger subs or another 10 in the box

Should probably fix what you have to maximize potential, before trying to add more.

Just sayin'

I'll probably go with 2 12 for the amount of airspace I have

You may be able to run 2 12" subs in this box. But a single 4" port won't be enough.

 

Put some big pieces of wood inside the box first, and listen with your current subs. you could like it.

Yes, remember.  The box is more important than the drivers so start by optimizing that.  Of course optimization of a box requires knowing what drivers you will use.

Thanks everyone for all your help and input. Will try and optimize box and use the drivers I have. My head unit is giving some trouble so I'm gonna get it exchanged first