Hmmmm. This is interesting, but not totally positive.
I brought 2 USB sticks with tunes on them and gave it a shot. The salesman was very cool and let me play for a while. Once we figured out how to access the stick and play the files, we were off and running. Most of the .flac's returned "unrecognized format". I didn't pursue it any further. But the 24-48 and 24-96 5.1 wav files did play.
I did not have a test tone file with me, as I didn't have time yesterday to put one together, so I had to go by ear on the music tracks that were on the stick. I can pretty much verify that the center speaker
IS the center channel of a 5.1 file. Many of the files that played had a Steven Wilson-type vocals in the center only mix, and sure enough, the center speaker in the dash had the vocal spot on center. It was not in any of the other speakers.
However, the 4 other channels were very hard to "find". Since this system has so many speakers, I am really not sure which ones are supposed to be what channel. The routing of the audio to these speakers is a mystery, as there is no clearly defined FRONT LEFT and FRONT RIGHT as you would have if there were only 4 speakers with a center. I recall in one of my older Acura's that the rear doors actually had front channel info routed to them, and before I realized that I thought I had screwed up in my DVD-A creation.
So, without a test tone file, it's hard to tell what speakers are assigned to what channel.
Since I was more interested in "if it played" than "how it sounded", I did not futz with the bass/treble/balance or any of that stuff, but will next time. I didn't drive the car or kick the tires, but the interior was very cool and a bit un-natural, with respect to changing gears and using the screen. The touch pad does take some getting used to, as unlike a laptop touchpad, this one has no "button", so you drag to a location and just press. It would obviously take a bit to get used to the whole thing.
The heads up display is a bit spooky. The all around camera is odd looking, and the display screen does not recede into the dash when not used.
Sorry, no pictures. All of the RDX's at the dealer were sold and in the back. I got to go back there and play, but it was not conducive to picture taking.
One thing that struck me as being a future REAL ANNOYANCE is that there is no tree structure to the files on the USB stick, it just picks a file and starts from there. This would mean a user would be better of with a lot of little sticks than one giant stick. Maybe I missed something, but this is pretty crappy, IMHO. I was expecting something like Oppo gives you with their players.
So, unfortunately, my answer to the ultimate question here is "Not sure". The key is the speaker mapping of the main 4 channels. Yes, it does play the files, so in that sense the ELS guy was right, it does PLAY THE FILES. But does it play the files properly? That, sadly, remains to be seen - by me.
Now you guys try!!