Clone the tracks you want to send to your artificial space. Route the cloned tracks to a bus and put the reverb in that bus. Set the reverb to 100% wet with 0 pre-delay. Use the volume fader on the cloned tracks to set the amount of reverb send and then move the cloned clips backward in time to achieve the desired amount of pre-delay. 

Thanks gents - theses are interesting takes on the routing.
Initially, my view was to look at this from the perspective of a stereo pair of mics in the rough center of a reverberate field - what I'm curious about is:
 
1. Whether it remains a one to one relationship on the timing of driving the reverb field.
2. Can you simulate a difference in distance - not by delaying the dry signal - but delaying the reverberant signal.
3. Can filtering ( EQ ) offer ques to distance - purely in respect of the reverbs field. This is where the seperate busses might be the better routing option.
 
I've never really liked the idea of using multiple reverbs. It creates a cluster in my opinion. And the singular pre-delay for entire feed to a reverb does allow cleaning up a mix but interferes with defining depth when applying wet and dry delays to tracks. So, I'm looking to apply delays and panning to set distance and spacial location - but also depth information via pre delay reverb and filtering to help define depth of field.
 
 
 

Just a thought,, What about exploring Surround Sound options...There must be reverb plug ins that work in 3D? 
 
This is also something new I am seeing in Sound articles. Object Based Mixing. 
https://www.audioadvice.c...und-dolby-atmos-dts-x/

So, the way I would do this is to set up each "pre-delay" on it's own buss, and then direct those busses to the reverb buss. Then I'd SEND from each track to it's appropriate pre-delay buss.
 
However, if I wanted to keep the pre-delay close to each track and not clutter up the buss area (it's a legit requirement in my book) then I'd SEND TO NEW AUX on each of the tracks, then point each of the AUX tracks to the reverb BUSS. Essentially it moves each of the pre-delay busses up into a track.


 


This was my thought. I wasn't clear on just where to control it from. You articulated it better than I could ask the question.  :)

Cactus Music
Just a thought,, What about exploring Surround Sound options...There must be reverb plug ins that work in 3D? 
 
This is also something new I am seeing in Sound articles. Object Based Mixing. 
https://www.audioadvice.c...und-dolby-atmos-dts-x/

I never thought of digging into surround processing, I have a ton of good reverb plugs - but I don' think I have one specifically designed for surround -. Though maybe there's other routing options within surround that will get me there. Thanks.

Well I thought it was worth mentioning as the whole idea behind it is to create 3D soundscapes for immersive sound. I think this is what you're trying to achieve is it not? 
Placing instruments left and right is easy,,, now move it forward or back and things get interesting. 

Cactus Music
Well I thought it was worth mentioning as the whole idea behind it is to create 3D soundscapes for immersive sound. I think this is what you're trying to achieve is it not? 
Placing instruments left and right is easy,,, now move it forward or back and things get interesting. 

Yes -   I can set-up a surround - I don't I'd want to mix all my material to surround format. It's more about researching how to localize instruments in a stereo field.

Try the Sonitus Fx Surround. You may need a surround bus for it.