Reverb and delay add reverb and delay, and not depth particularly in my experience. Maybe an illusion is enough, but level is key and burying an instrument in reverb tends to obscure its position in the mix more than accent it. Listen to the infamous brilliantly recorded later Steely Dan recordings...one of the first things you notice is the utter lack of reverb.
What affects front to back depth in room/ system?
I've been moving speakers around for a while now trying to maximize their placement for a happy balance of soundstage width, focus of center image, vocal height, instrument placements, etc. I want to get the speaker placement settled before acoustically treating the room. The room is 15x20 with 8' ceilings. Speakers are setup along the 20' wall. I'm pretty happy with most aspects of the sound, but what I can't seem to figure out is how to improve the depth. Honestly, I'm not sure if what I'm after is attainable to begin with. Is it possible to have depth that reaches the listening position in a 2.2 channel sound system? The depth behind the speakers is great, just not much in front of them- unless it's one of those songs that has a part where it has that inverted phase trick. Then it washes over me. I want that all the time. Any feedback and advice is appreciated.