Soundstage

Have you tried putting nothing, zero, zilch between the speakers? That made a huge difference for me with my speakers 30" from the front wall. I had my tweeters 45" from the side walls. Huge soundstage side to side and top to bottom. Depth of soundstage was pretty good...but I've heard better (speakers were 12' from the front wall).

A soundstage which routinely "extends beyond the speakers" is a characteristic often found with wide-pattern loudspeakers in situations which result in strong early same-side-wall reflections. These reflections broaden the apparent source width (ASW), according to Floyd Toole, and are considered to be desirable by most listeners (and undesirable by some). Their downside is that they also degrade image precision and can cause coloration (according to Geddes), can degrade clarity (Griesinger), and can contribute to "small room signature", which is the imposition of your room’s acoustic signature atop the venue signature on the recording. (Note that recordings which are deliberately intended to image beyond the speakers, such as the aforementioned "Amused to Death", DO NOT rely on strong early sidewall reflections.)

Chili42 I expect that your wide room’s inherent lack of early sidewall reflections is why you aren’t experiencing the wide soundstage that you expected. I’m among the (apparent) minority who prefers the attributes which accrue to freedom from those early sidewall reflections.

In particular, if we can solve the frontwall (and possible back wall) early reflection issues, you MIGHT end up with a system where the acoustic signature on the recording tends to dominate over the acoustic signature of your room. Ime this is quite enjoyable, and can result in a "you are there" experience which varies significantly from one recording to the next, instead of a "they are here" experience whose spatial qualities are dominated by the playback room.

Imo, ime, ymmv, etc.

Duke

A few thoughts:

A deep, layered soundstage is fairly difficult to achieve IME. Choose a couple recordings to use as a reference that will give you a basis for judging your progress. "Coal Train" (Hugh Masekela - Hope album) and "Roughest Place in Town" (Stevie Ray Vaughn - Couldn't Stand the Weather) are good audio show favorites that have a lot of depth in the right system. If you are into Classical music then Massenet (City of Birmingham Orchestra, Klavier Records) is almost eerie on the right system. I have a pair of Thiel CS6 speakers driven by a Krell KRC-2 and KSA 300S. I have a big room and lots of flexibility of placement. The speakers are about 5 feet from the front wall and 4 to 5 feet from the side walls and about 9' apart.

Speaking of audio shows, they are coming back this year and going to a show is an excellent way to calibrate your ears and figure out where your system sits in the scheme of things. At the shows I've been to I have heard excellent soundstage depth on only a few systems. Most have excellent articulation in the left/right dimension but most do not really allow you to see deeply into the soundstage.

There are several pieces of gear that do what you are seeking. Carver made a "Sonic Holography" C9 processor (I have one) that adds depth but you have to sit right in the sweet spot to get the effect. You might have to be patient to find one but they are not very expensive on the used market.

A company called BSG made a processor with the model designation of QOL that also performs this function (I have one of these too). I like this processor better because it is more forgiving about exactly where you are sitting and the effect is a little more subtle than the Carver. These are more rare than the Carver but if you patient you can find one for under a grand.

The other option I know of is the Atmosphere by Synergistic Research. I heard one of these at AXPONA and it was pretty amazing on a large pair of Magicos. I'm looking forward to hearing one of these again.

I got a nice confirmation about my system when an audio buddy visited for a few days recently. He is the guy who sold me the Thiel speakers. He was very impressed with the way my system sounded and particularly commented about the soundstage depth. He could readily hear the positive difference from the QOL processor. He told me that he had never heard the Thiels sound that good in his system.

Duke is right and I set up my system in a similar way with essentially no early reflections. This results in a more focused, palpable image. Whether you are "here" or "there" IMHO depends on the recording. A good live concert recording will put you "there" assuming your room acoustics are controlled. Studio recordings are a toss up and frequently very confused with various instruments and voices in entirely different environments. Overdubs can be very weird then the engineer adds some reverb to the voice and puts it over in the next county. I like it when the instruments seem as if they are in the same room together an effect that seems to be difficult for engineers to achieve. I really like a good studio recording but I admit the recordings I like the most are live. DTD records are wonderful for this very reason. 

Thanks Duke. If I’m understanding correctly you are describing the kind of sound that I really like (with the early sidewall relections). Found in bipoles (e.g. my ancient Mirage M3s), wide dispersion bookshelf speakers (my LSA bookshelf) and I would guess omnidirectionals. The speakers disappear, and you can walk around the room and the speakers remain disappeared.  Not a goal, just a description of a kind of sound I like.