Why do you keep insisting on mid bass. A subwoofer is not meant to be just a mid bass unit. The OP didnt ask for a mid bass unit only.
If you read my first post carefully, I did not suggest an expensive sub for OP. I just said that the review of cheap subs or rather mid bass unit like PA-150 was not a direct comparison to more expensive subs that have better low end extension. You just cant compare a mid bass unit to a real sub as there is just no output at the low end of the mid bass unit to compare with that of a real subwoofer.
You are accusing me of suggesting an expensive sub (even though I did not), but how is it fair for you to suggest 2 PA-150's to bump up the mid bass when the budget is $300? Please stop insisting on mid bass. The OP asked about a subwoofer, not a mid bass unit.
My problem is your comparison of a mid bass unit like PA-150 to more expensive all round performers i.e those that also give low end extension and say that the PA will hold its ground. Sure if one wants a mid bass unit for $400, it may be ok. But not if one wants low end extension.
It is also not true that there is not much content below 30Hz in movies. If you look at the list of movies with bass, many have content between 20-30Hz. I understand if one says there is very little below 20Hz. I myself said in many threads that getting a sub that goes down to single digit is an over kill. But if you miss out between 20Hz to some 30 or 35Hz as it is in the case of PA-150, you are missing a lot. You are missing the real bass!
If budget is really fixed, at least go for something Klipsch RW-12 D that has some low end extension and something that you can call as a "subwoofer" than a mid bass unit like PA-150.
If the title of this thread were like $300 mid bass unit and people raved about the PS-150, I would not have any issues with that. I rest my case.