All devices supporting Dolby Atmos will receive the signal from services correctly. How various devices deliver that signal varies.
Those using disc players know that a “Bitstream” setting gets the job done by simply sending the audio signal to the AVP/AVR for decoding and processing of it.
There are streamers such as the Apple TV 4K 3rd Gen and Amazon Fire Cube 3rd Gen that do not support bitstream. Rather, when audio is set to “Best Available,” these devices will re encode the signal to LPCM for output and can retain Atmos metadata for delivery when doing so.
All good here.
The bandwidth needed to deliver signals using those devices and settings is increased and many don’t realize that connecting them directly to TVs that only support ARC will result in less than optimal signal output to the receiving end.
By "less than optimal", are you referring to ARC limited bandwidth for lossless surround audio streams vs eARC which can?
While the Amazon Fire Cube does have a Dolby Digital Plus output option that supports Atmos/DD+ and will work over ARC, the Apple TV 4K does not have this option but only a DD 5.1 option that works over ARC. The “Best Available” setting is the only one that will support Dolby Atmos.
I am a bit confused by the comments regarding DD+ and how different devices interpret the stream differently, so below is a specific example to use as a reference.
The streaming device is an Apple TV 4K (2nd Gen)
Connections and devices are:
ISP (comcast) -> cable modem (bridge mode) to router -> Apple TV -> TV's HDMI eARC -> passthrough -> HDMI eARC to the Sennheiser AMBEO Max soundbar.
The AV cables are all HDMI 2.1 or better for eARC
Network is 1.0 Gbps to the router and Wi-Fi 6 to the Apple TV ~@250+ Mbps (or 900+ Mbps over ethernet).
Apple TV settings
1) Audio Output = "Auto, Atmos Available"
2) Audio Return Channel = eARC
3) Audio format is "Dolby Atmos."
Apple Music App Settings (on the Apple TV)
1) Audio = Dolby Atmos
2) Audio Quality = Lossless (ALAC up to 24-bit/48 kHz)
Sennheiser SB01 relevant settings,
1) dynamic range compression is off, i.e., full dynamics
2) "Dolby Virtualizer" is turned on which allows Dolby audio content to be played back unchanged
Theoretically, this system should easily handle the lossless Apple Spatial Music (24-bit/48kHz) as lossless and the soundbar sees an Apple Music stream as "Dolby TrueHD Atmos", i.e., not lossy., am I missing something? (I've contacted Sennheiser about the accuracy of their app and will let you know the answer).
AppleTV can transport TrueHD Atmos to an AVR (or equivalent) just fine using Infuse.
I thanks.
EDIT: My objective is two-fold, to clear up the confusion around Atmos streaming and to understand if one can generalize streaming lossless Dolby Atmos music to streaming Dolby TrueHD Atmos AV content; specifically, when streamed can today's hardware and software properly handle Dolby TrueHD Atmos 4k movies (economics aside)?