Anything with a "BBC Dip" and a warmer less defined bass will tend to give you a deeper soundstage. Upper midrange rolls off with distance and bass sounds less tight or crisp as you get further from the stage.
Rogers is a classic example but many follow the same design principles. Look for a speaker plot with a dip in the upper midrange and particularly a roll-off in the off axis response in the upper midrange (off axis response clues you in as to where instruments are - if it is in your room and close to you then the off axis response is very strong as you will well know if you play an instrument - if the sound is far away then the off axis will be even weaker or more attenuated - these are all clues that the source is far away giving the impression of a deeper soundstage)
The room is very important for this as is placement. Got any room treatment?
I had a pair of JMLab Electra 926's that put out a soundstage exceeding the boundaries of the room that they were in ! They are the only speaker , that I have heard , that created a soundstage behind me as well !
It is partially dependent on the source and software too .
Room is good...and the sound itself is very pleasing to my ears...it's just I lack the depth that I know some recordings have. I'm thinking of trying something else other than those B&W's...old but mint!!!
sideways...i own 3 pairs of castle harlechs and they are superb.....an incredible value too.
s, b+ws have a bbc style dip in the mids and imho, tend to compress the perspective and have less less natural contrast than a speaker with a flatter amplitude through the middle. so what you really need to think about is if you want a speaker that protrays things in a more distant way or a speaker that sounds a little more imediate but actually shows more depth of field.
for eg, hold a record jacket at arms legnth parallel to the floor and see how the 12 inch depth looks considerably less than 12 inches. now move the jacket up to your nose and still parallel to the floor and notice that the record jacket actually looks deeper and less compressed in depth.
so, do you want more depth or a more distant perspective? they are not the same thing.
There are a lot of things that affect percieved depth: speaker choice and design, amps, sources, placement and room.
I've got a friend who comes over and likes to toe-in my speakers for his taste but I prefer them with no toe-in because I want a laid back soundstage. I've got dipoles and that may not apply for yours.
Get the speakers the greater of half their distance to you and 4' off the wall, don't sit much farther away than it takes for the drivers to properly integrate (7' from a line drawn through the tweeters with speakers positioned in an 8' equilateral triangle works for 4' high speakers with woofers down to floor level), and get back to us.
Placement has more to do with image depth than the speakers you bought.
What amps, tubes, interconnects, speaker cables are you using? Is there anything standing between your speakers? Everything is critical when trying to recreate ambience information with a system. If that's an NAD 3020 you are referring to: SS generally does not exhibit much in the way of sound stage depth.
Keep the speakers and improve your source.
Get newer amp.Use NAD in second sytem.If you can swing Unison Unico or Pathos Classic II (both hybrids with 75 wpc+/-) or my EAR 324 with 40 watts you'd have better sound for newer speakers.Always comes down to money right?Good values in efficient speakers include Silverline and Hyperion,some like newcomer Zu.Instead of B&W 805's (I used to sell them till 2001) I'd pick Revel monitors.If going for broke stick Brit and get Harbeth.But for value look at Usher 719's,Silverline,Totem,Quad etc.Give a budget.One thing I find is a real fine room treatment (other than ASC tube traps which has low WAF) istreating wall Behind speakers with sonex tile,wood diffuser or even a rug.But as always these choices are deiced by budget and what's nearby to hear unless you want to follow us or online mags.I like 6moons choices even though they leave out some I like (There hot on Gallo's with you can get for less than $2K,have incredible wide dispersion tweeters,and decent 35Hrz bass and 20 hrz with added $1K amp).But again look for spending some bucks on companies mentioned that offer a lot for buck as mentioned above.
Good point - as you figured out - I merged "distance" and "depth" in my comments .....how far something is away versus how "deep" is the perceived soundstage.
Thanks for clarifying and making my comments clearer. If I understand correctly - you are saying that a system that is designed to sound distant cannot give as deep a soundstage as it will tend to make all recordings sound distant. Did I get it?
speakers that sound distant compress the depth of field. they also sound deeper than they do, wide.
a speaker with a hole in the mids sounds distant. play a soloist in front of an orchestra on one of these speakers and it sounds like a distant wall of music.
play it on a speaker with a more uniform midrange and the soloist will sound closer to you. but the back of the orchestra and rear hall wall show much more contrast to the soloist as far as layering and ambient information is concerned. the stage width sounds more equal to the depth too.
How about a dipole or bipolar design?
increase your speaker distance from the front wall, if you can, and also remove items from in between the speakers, like equipment stands or TV's, if you can.
if you can make those modifications in speaker placement to your system and it still doesn't work, then perhaps it is time to purchase a new pair speakers or amplifier. you would be very surprised how much an amplifier can affect the sense of soundstage depth. if you do not have the ability to adjust your speaker placement due to other room-use constraints, then you are forced to compromise your system and shouldn't expect to achieve optimum performance from your system.
The improvement in soundstage lies in a change of speakers. You mention that the "room is good",so we can assume that battle against reflections has already been won.
I suggest the Morrison Audio point-source omni-directional Model 17: these speakers should quickly solve your problem. They deliver the richness and depth of a recording, and you'll know where all the instruments and vocalists are located.
Dipole or speaker with rear firing tweeter might be good.Look at Emerald Audio C2's a tweekgeak.com.Just wanted to add a bit with my list I just got a $1400 self amped pair of Quad 11l's and hey are fine (great deal on ebay $400 for $1400 list)Their 12L amped or larger 21/22 speakers are good values.Also in that list always thought NHT put out good lower end products ad hear new line is very good.If you want to pull speakers in for near field small collum speakers like Audio Physic Sparks are in that group.Same fo narrow totem Staff.II had a par of friends Sparks for a while and they had great sound ,different dispersion (really good for long wall) and were small and light so one could easily pull into room.