As we often discuss on this forum there are no "rules" so it all depends on the effect you are after - and then using the equipment/tools you have to achieve
So...should the reverb be panned to the same place as the instrument, or all the reverb go into one "general" stereo reverb track?
If you are going for a "real world" sound then it is useful to think about sound in the "real world"
Let's assume we are standing at one end of a large empty warehouse
Directly in front of us (about 1metre away) is someone bashing away at a piano
What do you think we would hear?
I think we would hear the piano "loud and proud" in the centre, followed by a "wash" of reverb as the sound waves bounce around the warehouse and eventually reach our ears
I think the "wash" of reverb will completely fill the stereo field, since it is sound bouncing off all of the walls, ceiling, floor, the piano, and even us!
We now move the piano away 5metres and push it to the left hand side of the warehouse so it is 10 metres off-centre (to the left)
After a rest (pianos are heavy
) - we sit and listen to the sound
The direct piano sound is now definitely coming from the left, although it is not as prominent as it is further away - it is not only quieter in volume (being further away) BUT the direct sound waves are hitting our ears at the same time as some of the waves being bounced off the walls (eg the left hand wall), ceiling, floor, etc.
But what about the general "wash" of reverb?
The sound still bounces off of all the walls so I do not think there would be a definite pan position to this reverb
If you think of this "wash" of reverb as your "send" then I hope you will understand that it is less important (or even desirable) to pan your reverb to a particular position (especially if you are going for a natural sound)
Now, let's get creative...
We decide to "mic up" our piano and hook it up to a guitar amp, with the reverb cranked up
What do we hear now?
I think we would hear the sound from the piano coming from the left, I think we would hear the piano with reverb coming from the guitar amp (which might be a "spring type reverb") also coming from the left, BUT we would still hear the "wash" of reverb from the "space" we are in (the warehouse), which would sound like it is coming from everywhere (ie the whole stereo field)
The guitar amp reverb is acting like an "insert" reverb in this example and as you can see is effectively "panned" with the instrument
But - and here is where things get interesting - the "spring reverb" coming from the guitar amp will also be affected by the "space" it is in - in this case the warehouse - as it will also bounce around the walls, ceiling, floor etc. - and would also just hit your ears in the stereo field and not necessarily at a defined "pan position"
So to replicate this in your DAW...
You would have your piano on a track panned left
You would put an "insert" effect of a "spring reverb"
You would put a send to a "large space" stereo reverb
You would send your piano sound to this space reverb (if you wanted to get technical you could even programme a stereo reverb to give the impression it is near to a wall on the left had side using pre-delay, reflection timings etc. - or you could even programme the reverb to replicate some curtains hanging up in the space - or we could even capture the reverb characteristics of a space we like using Impulse Response (IR) files - but this is all a bit technical for this example
)
You would also send some of your "spring reverb" to the "space reverb" to recreate the environment having an impact on the guitar amp's reverb sound
This is a simplistic example but I hope it helps you get your head around reverb
The goal is usually to have a consistent "space" (or "ambient") reverb send so it sounds like your instruments are in the same "space" - BUT - you can still have lots of other reverbs set up to add some spice to your track
If you are using "send" reverbs then you can always add a touch of your "spring reverb" to the "space" reverb, to get a sense of consistency, by adding a reverb send to another one of your your reverb sends
I now tend to have at least 4 reverbs set up - a "short" reverb (usually plate), a medium (eg small room) reverb for vocal "ambience", a longer reverb for effects (chamber or hall) and a general "ambience" reverb (eg a medium/large room)
These are the "rules" as I see them for a realistic sound
Once you understand this you can start "breaking the rules" for specific effect - eg why not pan a huge reverb?
An effect I like to use is have a dry signal panned one side and then pan just the reverb to the other!
One final word of warning...
Whilst using lots of reverb can be great fun it is a sure fire way to muddy your mixes if you are not careful
Don't forget to EQ your "dry signals" and also don't forget that you can add EQ to your send channels - for example you can take the low end out of the reverb tails, which should help you maintain control of your mix
Hope this helps...