Room setup...diagonal or standard and how to treat

Hello, I have a room that is 14 X 16 with 8' ceilings. I use Dynaudio C1 speakers and Mac and Esoteric gear on a 5 shelf rack, sitting beside a 36" TV. This is a room for both myself and my family. Here's the this 14 X 16' half of one of the 16' walls opens into the dining room and there is also a doorway along the rt rear of the 14' wall.

! 14' (a) >> !
dedicated !
opening to lines !
dining rm. !
<< \
16'(a) ! 16'(b)
! !
! / 8' ceilings
! !
! !
! !
! doorway !
!____________14'(b)__________ _!

My question is....what is the best way to set up my system. Diagonal? Along the 14' wall (a) to take advantage of the dedicated lines placement? I seem to have lost bass and brought more upper detail to my soundstage when I recently tried diagonal facing out from the dedicated lines corner. The opening to the dining room is a problem I assume and wonder how best to minimize its effect. Lastly, what type of room treatment would you use and where after there's a concensus on the room setup. Thank you all for your generous time.
Sorry, thought the diagram might work. Will try alternate method. Thanks anyways. Dave
Diagonal setup can be great from the audio viewpoint, but is rarely even attempted. WAF you know.

First I think you are being very smart by looking into acoustic treatment.

I would recommend a diagonal setup because you almost have square dimensions. This will give you the best results (I know from experience). However, it is a trial and error process since you won't find a lot of information about it compared to the typical placement.

You can go to Michael Green Audio, Eighth Nerve, or others (or DIY) and get a floor stander to put in the space where it opens up to the dining area. This will simulate a wall and will help give a better soundstage.

Here is a link that should help solve your frustration. A big thank you is due to George Cardas for this free service.

Room Set Up Guide
I can't validate the results, but here is a link to an article by Steve Deckert of Decware concerning diagonal room placement.

Go to the Decware site at:

Click on "My Room" then scroll down to "How to set up a room with no treatment". The article is about diagonal room placement.