Does larger sub necessarily mean better or deeper bass?

[mrpep]

More moving mass generally means lower lows but any 10 or 12 can play 20hz. They just don't do it with the authority of an 18.

Yes, and this is what I also believe but seems like not all agree . I think I will jump into a budget 18" like the dayton on parts express so that I dont invest too much into this. One crazy thing is that they recommend liek 4c.ft on those subs and they have designs for ported and sealed - i prefer ported but will be bigger.