Lack of depth problem

A thought, beyond the set up issues and choice of electronics both of which play a great role in creating a good sense of front to rear depth of image and which we cannot comment on because of a lack of specific information. (BTW what are you using for electronics and how far are your speakers apart and how far from side walls, what have you done to reduce/eliminate first point reflections which are killers for good depth of image.

Are the sources you are listening to recorded properly so that the depth of image is present in the recording. Most are not so it is not unusual for absolute depth of image to be missing. Like trying to get blood out of a stone.

Do you have sound panels on the wall behind the speakers? Sometimes overly damped front or side walls can reduce the perception of depth, since you might get very little ambient information.

What are you driving them with? There are a lot of amps that allow no sound stage depth(few SS amps will). My Cary monoblocks will, and that depth increases dramically with the right driver tubes. There are more variables than just the speakers. Lots of things get in the way of ambience recovery(amp/pre/source/tubes/cables). Your room dimensions sound really nice for audio. Is there anything between the speakers? How far apart are they? Did you have much depth with the system before changing the speakers? This CD contains some tracks that are excellent diagnostic tools for setting up your system: (http://www.chesky.com/core/details.cfm?productcode=JD037&category=1)

I'm not a proponent of the parallel to the wall camp.

Generally speaking, and that is not carved in stone, I find most speakers sound best when they are toed in so the inside surface is barely visible from the listening position.

Different dispersion patterns and listening preferences will, of course, be the final determinants.

Agree with Newbee. Check out the Cardas site. Use simple (one/few performers, acoustic instruments, NOT multitracked heavily mixed rock), analog recordings (NOT digital) for optimizing. A good starting point for your speakers should be between 5'-9" and 7'-8" from the wall behind the speakers. Try to have as much room between the speakers as possible leaving a few feet on either sides (your room is narrow). Using a string make sure the distance from both speaker to your listening position is equal. Do not toe-in the speakers initially. Simply start at one distance from the back wall and move them 1" at a time until you have optimised the location. Once there, use smaller increments. Use minimal toe-in until the image "snaps" into focus. Always try one position and compare the sound with the previous position. Listen to the "accuracy" of the bass, naturalness of vocals, and other instruments.

This is a long, tedius process and can take several months to get right. Enjoy.