bass suggestions 12 x 16 room....

You need bass trap pure and simple. This is your bottom line need and it will get you what you are looking for period. Buy GIK corner bass traps stacked floor to ceiling in your corners and you will be amazed.

The suggestion for sealed box speakers is a good one, in my experience. I've got a room of similar size, and had good luck with a pair of little Spendors (forget the model), and I'm back to using my beloved Celestion SL-700s. It took about eight months, but I finally got 'em positioned just right. (Long wall, about a foot and a half from the rear of the speaker to the wall.) I tried several ported designs, but couldn't get any of them to work in that room.
Good luck.
-- Howard

After moving to a new house I went from a very large room to a 13'X16' room and I would say it has been a challenge. Only my problem is in the opposite direct. Little by little the system is coming around after trying several speakers, amplifiers, CD players and cables.

I have lived with a 16x12 room for ~20 yrs. now and have tried dozens of different speaker positions; and what has worked best for me is an "asymmetrical placement". Meaning the speakers aren't placed on the long or short wall but instead I had them firing across the diagonals of the room. With MUCH trial and error I was able to find spots where the bass didn't boom (and obscure detail) and I could have a wide/deep sound stage with palpable/dimensional images populating that space.
Eventually I found several "G" spots of the room.
Have tried it successfully at other friends systems so it's not just a my room thing. The biggest hurdle for most people seems to be that it looks funny and/or their significant other wouldn't go for it.
Let me know if anyone out there tries this and agrees it has merits.

Phasecorrect , there is never a straight answer. No two rooms are the same.
Since bass waves can easily travel through walls, some of the interference
patterns in your audio room may result due to waves reflected by walls of the
neighboring rooms.

To determine the best place for the speakers, i.e. that excites the minimum
amount of room modes, I recommend to place the speakers agains each of
the walls. Of course, the position of the listen chair is also critical, i.e. make sure
you are not siting in spots where you have destructive (no bass) or constructive
(too much bass) interferences .

If you have the possibility to do this, you would be surprised at how significantly
different the bass is when going from on wall to another.