I'm playing the two "audio-only" Blu-Ray discs I got from Amazon to try out the concept. This is using a PS3, an ARC'd D2, and a 5.1 speaker system.
The two discs I got -- both produced by "Surround Records" -- are the Vivaldi "Four Seasons", filled out with two "Concertos for Double Orchestra", and the Rachmaninov "Piano Concertos #2 & #3". These are high-bandwidth, 5.1 Naxos recordings originally produced for SACD. Surround Records has apparently processed them to add the additional rear channels and they are on disc as DTS-HD MA 7.1 24-bit/96KHz.
The Vivaldi contains 63 minutes of content and the Rachmaninov 74 minutes -- which would be nigh unto empty for a Blu-Ray disc with no video. However the PS3 reports that what it is actually seeing for these is an AVCHD recorded on a DVD-R!
And indeed there's something funky about the way they did it, because when you get to the end of the recording the PS3 gets confused. When you reach the end of the recording the disc does something like a Pause. The disc does not Stop on its own, nor can you Stop it using the remote. If you Eject it, it does in fact come out (thank God), but the PS3 still thinks it should be playing it because it doesn't go back to displaying the PS3 menu! And if you stick in another disc you get an error message from the PS3 saying you've inserted "The Wrong Disc".
So far, the only way I've found to get out of this state is to hold down the PS3 front panel power button long enough to force the PS3 to shut down. When powered up again, everything is back to normal.
*** ETA: This problem at the end of the disc actually only happens with the Vivaldi as it turns out (I was typing this while playing the Rachmaninov). What the Rachmaninov does is restart from the beginning even though Repeat play is *NOT* turned on! But at least you can stop it at that point and get back to the XMB. ***
That aside, the discs play just fine. They have no pop-up or Top menus and so they start playing without having to navigate any menus. Selecting Top menu during playback causes the disc to restart from the beginning. Selecting the pop-up menu does nothing.
They appear to respond normally to track forward/back operations.
They have just the one audio track, but apparently the liner notes say they WILL play the "core" DTS 5.1 track if your player or receiver can't handle the DTS-HD MA. There are, of course, no subtitles or angles.
The "video" is a black screen that the PS3 identifies as MPEG 2 at 909Kbs.
The audio is, as expected, DTS-HD MA 7.1. The bit rate on the Vivaldi varies between 10.5Mbps and 13.5Mbps. The Rachmaninov is not quite that high running from 9.5Mbps to around 12Mbps
Through the ARC'd D2 -- with the PS3 merging the rear channels back into the side channels to send 5.1 -- the audio sounds very good indeed!
This "Four Seasons" will not be one of my favorite recordings. The liner notes aptly report that it, "is given at houghtful performance." And just like that typo, it's a little bit off. But it SOUNDS wonderful.
The "Concertos for Double Orchestra" were something unexpected! They were recorded with the soloist between two orchestras -- one of which was put into the front channels and the other of which was put into the SURROUNDS!
Quite startling to say the least until you figure out what's going on! But my oh my it does show off the value of letting ARC do a full range correction on your surround speaker setup! For this recording you really do have to sit in the primary seating location (ARC mic #1) or the completely surrounding sound stage is just too distracting.
The Rachmaninov pieces were presented in the more traditional sound stage, thank God. I happen to like the Kissin performances of these better, which are not as traditional as these here by Scherbakov, but again the audio quality seems quite good indeed.
So apparently there are still some kinks to get out of the "audio-only" Blu-Ray system here. In particular it is ridiculous for them to have issued these before verifying that a PS3 still works properly after reaching the end of the disc! I mean it's only the single most popular Blu-Ray player out there -- by far.
And I suspect the resort to AVCHD as the recording format is just a hack until the Blu-Ray consortium puts their official blessing on "true" audio-only Blu-Ray discs.
And as always, the CONTENT (in this case the performances) is fundamentally more important than the TECHNOLOGY of audio delivery and reproduction, but I think these two discs show there is a lot of potential for "audio-only" Blu-Ray as time goes on and more recordings come out.
And also, of course, it sounds very VERY good indeed through an ARC'd D2!