Room Acoustics and Speaker interaction.

I would like to have a secondary system in my small den which is only 11.5ft by 11.5ft with only a 7.5ft ceiling. Very small and very square...yikes!

So, because the room is so small, the speakers need to be close to the wall that resides behind them.

So this got me thinking about speaker types: sealed/front ported/rear ported, etc as I want to avoid a booming bass. But then I was it really the ports that are problematic or is it just certain low frequencies that are reacting to the room modes? Any thoughts?

How does one determine what frequencies to watch out for in your particular room?

I'm not saying the op has any problems. I'm just saying the room has more to do of the booming bass than the speakers themselves. You're right about the limitations of room correction but seeing from the options of the op, the room corrections seems to fit him best. His biggest concern was booming bass and that was MY suggestion.

Bmwmcab, my initial impression was that the OP is asking for speaker recommendation. However, after re-reading the initial post it is clear that that may not be necessarily the case. Though, I still can not tell whether the OP is just concerned about booming bass or he has already tried speakers in that room and knows for sure this is an issue. Sorry.

Regarding some of the OPs initial questions, the dimension of the room determine the modes that will be amplified or absorbed by the room. There are quite a few online room mode calculators (google "room mode calculator"). A few times I have used this one:

Room mode calculator

However, one should keep in mind that the position of the speakers relative to each other and to the room walls has a bit influences on the interference pattern. The speaker ports are also very important in this regard as they are additional bass sources. There are other additional variables, e.g. material from which the walls are made, listening level, neighbor rooms, etc.. Thus, unless one measure properly the response of his/her room, nothing is written in stones. The output of all these online calculators should be considered as a starting point.

Electronic management of the bass, as first suggested by Bmwmcab, is the most effective way to go. However, if you will used speakers design to be placed near room boundaries and/or listen at low level electronic equalization may not be necessary.
When I study about where to situate a pair of speakers I usually take some meditions:
1- find best frequency bass response (<200hz) in the room. You can play with speakers position AND sweet spot position
2- try to adequate the room reverberation time from 200hz to 3150Hz according to your taste preferences (room monitoring studio has typical values from 0,2 to 0,4). For this you will need acoustic treatmen.
3- find the best response over 200hz, play with toe in amd tilt of the speakers

Be careful with rear bass ports, they don't like rear walls...

Good luck!!

No offense taken. We're all here to help each other out and try to give advice to the best of our knowledge. Given the size of the room and where you want to place the speakers, I would go with Nvp's suggestion and get a front ported speaker and see how it goes. If it's still too boomy, consider room correction.
Hi guys,

Yes, I have tried some speakers in this small room already.

I've tried my late 1960's vintage 12" Tannoy Monitor Golds in custom cabinets that had dual front ports. Very boomy on the bass notes.

I've tried my late 1960's vintage Wharfedale W25's which are in a sealed enclosure, two way speaker with 8" woofer. No problems whatsoever, except that due to age, the cabinets are not up to my wife's approval for this room.

I've been thinking about the little Harbeth P3esr which is a sealed box, but it is a lossy design though. Or possibly the Harbeth M30.1 which is front ported, but a little larger than my vintage Wharfedale W25.

I've also been considering the DeVore Gibbon 3XL which is front ported.

There are no dealers near me for any of these speakers, however I will be attending the AXPONA show in Chicago and will be able to at least hear the Harbeths there for the first time.

So in answer to some of the questions from posts above....yes, this little room can have a booming bass problem as evidenced by the use of my Tannoy Golds, but at the same time, no problem exists with my sealed Wharfedale W25's.

So that is what lead me to ask about speaker design. Is the problem with ports, vs sealed design? Or is the problem with the amount of air the 12" gold driver can move vs the 8" driver of the Wharfedale?

I won't be buying anything until after the Chicago show. I appreciate everyone's willingness to help me with this and the sharing of everyone's thoughts and ideas. This IS a GREAT forum with very HELPFUL people. Thank you to EVERYONE.