Ok. So first text using my standard go to test file I wasn't that impressed. However. I just played some surround demos and Yessssssss. It's sorted. I still have the soundbar as low as it will go and the surrounds up as high as they will go on the settings but at the moment the rears are maybe a bit too loud. I'm reserving judgement as I have had them working before after an update only to find that the next day it doesn't work any more. Lol. But so far so good. Whoop whoop. Lol
I wonder if they fixed center channel bass...
Also does the rear vs bar volume difference decrease as you turn the volume up? It's how it works with ms650. At lower volume soundbar is louder, and after about 50/100 rears become louder than the bar.
I have never had a problem with no sub support for the centre channel and I have tested quite a lot. Volume balance between the bar and rears during volume increase and decrease is spot on as far as I can tell with the balance being good at all volumes I have tried so far. I will continue my testing though as it seems to good to be true at the moment lol
Just for you I have done some centre channel testing to check sub support. I definitely have sub running with centre channel. I wonder if someone e else can also verify this. The best scene to try is the opening of transformers the dark side of the moon. Optimus Prime narrates the intro. His voice is centre channel only and placing your hand on the sub reveals plenty of sub support. It's not so easy to hear in other circumstances. I imagine this is because the human vocal range just doesn't require it all the time. I wonder if your K650 was faulty?
I'll update it and check if anything has changed when I get back home.
It was very apparent with that Frauhoffer dolby test, where a male reads channel names. Nothing going through center channel gets sub reinforcement.
I noticed it first when someone here pointed at the issue, though ever before that male voices sound weird to me.
Just tested on my setup and it does look like they have fixed the problem at last.
Initial tests suggest that I will need the Soundbar set lower than the rears but that may just be my keenness to her the surround!!
I've been testing with the official dolby5.1 trailers which sound great and with the original test file that was circulated all those months ago in this thread - I can confirm that there is discrete 5 channel surround with equivalent level from fronts and rear speakers.
Regarding the sub support and centre channel I would agree that on the test file the pink noise has more sub content in the L/R than in the C channel but this will depend on how that file was originally encoded. I hear the same on the Frauenhofer test file and I am not convinced that the sub is decoding correctly but whether this is an issue on actual programme remains to be seen.
Note: More often than not in the real world (as opposed to test files) the sub channel is derived locally in the surround processor rather than being sent as a discrete channel in the stream - there is metadata to describe how to create the sub signal (both phase and amplitude) and this is processed by the sound bar. I think this may explain why people are seeing different results...
Some thoughts for others testing this:
 After the update powere everything down for a few seconds to reset the system - soundbar, TV, radiants and hub
 Dont rely on YouTube material to test - most of it is incorrectly encoded and will not give discrete front and rear
 Here is a link to the official DOLBY 5.1 trailers which you can download to a memory stick and play via the USB
Finally a huge thankyou to Rob for keeping up the pressure on Samsung - without your considerable efforts I dont think we would have got this update.
The easiest way to test sub support for me is by putting a hand on the membrane its always completely still during center channel tests, no matter the file I use,no matter the source (TV dolby test files, dolby ac3 file played directly from Multiroom app) .
It's like the active crossover doesn't work for center channel at all.