Originally Posted by meles
Don't have a receiver or htpc (yet!) so wasn't sure if you could put an SACD in a drive of an approved player and send it to receiver for upmixing.
Bear in mind, however, that some receivers can decode SACD (or DSD) and some can't. If they can't, the disc player has to decode SACD into LPCM.
Bluray audio discs are easy to imagine working plus hd downloads. I see some SACD players with hdmi output, so is that the only way is to have hdmi out on player?
Yes: HDMI provides the encryption that Sony requires.
Sony does not allow their SACD digital audio products to be transmitted unencrypted. They don't want pirates to be able to create bit-perfect copies of their high resolution audio products. Because of this, the earliest SACD players (before HDMI existed) sent the SACD audio only to analog outputs. SACD soundtracks were (and still are) downgraded to CD quality when sent over S/PDIF connections.
Two channel upmixed seems to be improved by Atmos
Atmos is not produced by upmixing. It's a way for a movie or music director to encode a 3D soundfield into a multichannel soundtrack. However, in principle at least, a computer could encode a 3D soundtrack into an Atmos container. As best I can tell from its descriptions, the use of the term Atmos to describe "Dolby Access" and Dolby's other new two-channel products, is, shall we say, very misleading.
and I like youtube etc. upmixed, but multi-channel seems to be levels better for sound. For stereo I have nice two channel system I really like. For multi I'm amazed how close deluxe Atmos soundbar does overall compared to premium two channel setups.
A full multi-channel speaker setup with speakers behind you and in (or on) the ceiling is even better!
Another question I have is whether all dolby surround is equal.
Yes: devices which implement Doiby Atmos decoding and Dolby Surround upmixing have to be certiied by Dolby.
My K950's surround setting is not nearly as good overall compared to what I get using the dolby access app.
Dolby Access is not Dolby Surround. The different name indicates that it complies with a different Dolby standard, although it might produce similar results. You have to be careful, too, because audio which is only very slightly louder usually sounds better.
Are all receivers equivalent when it comes to Dolby Surround processing?
Yes. See above.
However, some support more speakers. For example, some support only 2 overhead speakers, while more expensive models support 4 or even 6.
Are they identical to Atmos app when adjustments set to neutral?
Atmos soundtracks are designed by a movie (or music) director and by the person mixing them.
Dolby Surround applies a proprietary upmixing algorithm to 2.0, 5.1 or 7.1 soundtracks which extracts sounds from ear-level speaker channels and moves them to however meny speakers you have. The results are "random" and not what the director intended.
Is there some other format that might be achieved playing back media on a windows 10 machine other than Atmos?
Windows includes its own 2D upmixing software. Windows media player software (like fubar 2000 and Kodi) can pass-through other audio encodings like DTS:X and Auro-3D.
I'm about to do htpc with foobar as well to output upmixed Atmos to my sound bar.
Note my comments above. You can't upmix to Atmos, although you can pass-through a soundtrack which was recorded in Atmos format.
I'm not aware of receivers having HDMI output where one could feed a sound bar; is there such a preamp or receiver?
Unfortunately, they aren't intended to be used that way. You should think of your soundbar as being a specialized receiver which just happens to include speakers in it. You can plug your PC's HDMI output directly into the soundbar, for example. In principle, the HDMI output of a receiver can be plugged into one of a soundbar's HDMI inputs, but people who've done this have been, shall we say, less than happy with the results. That usually results in only a stereo connection.
Some soundbars are designed to be used with receivers, but audio usually is sent to them using speaker binding posts, not HDMI connections.