Tested breverb here, casually. I found some of the 'hall'-based presets treat L & R inputs differently. So it's analogous to "true stereo" (even though breverb is algorithmic, not a convolution reverb). Not clear about the algorithms other than hall. Some algorithm names sound like they are meant to be "spaces", while others are traditional "sweeteners". E.g. why should "plate" be true stereo?

How tested:
1) a mono file in a mono track feeding a stereo bus with VST breverb on it.
2) choose a "hall" preset (I used "experimental piano")
3) Turn 'dry' to -inf in breverb (by the way, note the pan controls o---- and ----o below the wet and dry sliders; you could even sum the inputs or outputs to mono if you wanted to).
4) note that no matter where the input from the track is panned to, the output is stereo, and the L&R outputs are not identical.
5) Now for the conclusion: note that the wet sound is different when the input is panned left compared to right. To me, space emulation reverbs should do at least this (hopefully in some kind of space-coherent way).

Tried this on some non-hall presets and did not notice obvious L/R differences. Did not try null tests.

I have not found any breverb parameters that could adjust or account for the L/R input differences for hall. However, the limited Cakewalk version is missing two tabs that might have real parameters in the full version.

Bill B.

Resurrection! 
 
 Hi LJB and others! 
 
Funny I found this thread as I have just discovered the same issue in Breverb 2. It really got me stumped too. I've been trying recently to just use Sonar plugs for mixes but have found that I have struggled with Breverb. My issue is that I found it was alot of work to get it sounding how I wanted compared to other Reverb VSTs. 
 
I have eventually got used to Breverb now and can just about get it to sound how i like. 
 
I have found Breverb smearing my panning when adding as a ambience room verb on all instruments.
 
In my mind having Breverb on a buss (100% wet) and then sending a mono source panned hard L/R to that buss, should put it in the reverb buss space on both speakers, however it should still respect the placement and sound stronger depending on what side panned. Breverb 2 seems to just put them in both channels equally. Messe up the stereo spread of mix. 
 
I tested the Blue Verb (part of the X3 suite) and it does in fact pan the sent mono signal in the reverb stereo mix. 
 
 
 What I could not glean from this whole thread is what IS the actual correct outcome. 
 
Should a stereo reverb respect the panning of the send placement from a mono signal to it's buss or not? 

How many of you guys have tried recording in a genuinely VERY reverberant space? One where you can actually hear the reverb?
The reality of reverb is that regardless of the position of the source sound, the reverb will come from all around you.  You can gauge the general size of a space by the early reflections, and if the source is close enough to a wall or other hard surface the initial early reflections will be very very slightly louder from that direction, mainly in the form of an echo.  But the initial sound will go off in all directions, you only hear the tiny fraction that heads directly to you.  Most of the sound that hits the nearest hard object will NOT be reflected towards you, but will in turn head off in all directions.  Thus is the nature of reverb.
 
I recorded the Christmas Carol service in Lincoln Cathedral in 1999/2000, the 3rd largest cathedral in Britain and for over 200 years, the tallest building in the world (until the central spire collapsed).  I can assure anyone here that reverb does not respect pan laws or stereo positioning.  In fact it's a real pain in the belfry when you're trying to record intelligible speech for radio broadcast...

+1

I believe the majority of reverbs sum the inputs to mono, then generate a stereo field artificially. This harkens back to when reverb was thought of solely as a way to create a "room sound." Although an instrument's direct sound would have a spatial location, the reflections would not be equally defined. This is why few people objected. 
 
However some people did, and for digital reverbs, when DSP became more powerful it was possible to have true stereo units that sounded decent. I think they're still probably in the minority, but haven't done any research to know one way or the other.
 
As mentioned above, the only way to achieve stereo reverb with a mono in/stereo out device is to use two reverbs. For me, this was never a problem because even when not needing/wanting stereo reverb, I typically used two digital reverbs so one could "fill in the cracks" of the other one.

I haven't had a chance to look into this more, but I'm also thinking that some stereo reverbs read then put as mono and generate terror reflections...

I don't know if that's the case here but I thought to mention it...

Keni

Personally I'm not a fan of too much stereo reverb in a busy mix. It just seems to take up too much space and reduces clarity, to my ears anyway. Sometimes I might use a tiny amount of a short room ambience on a drum bus, and I might use a nice lush stereo hall reverb on a solo synth part in a sparse, ambient mix, but if its a busy track then I much prefer either mono reverbs (panned LCR) or just doing away with reverbs altogether and using delays to create space.

+1 with Karyn on this one. Very well said:)