There is no difference whatsoever in audio quality between an optical and ARC outputs.
The optical (S/PDIF) and ARC on this TV are both limited to a maximum 5.1 DD or 5.1 DTS lossy
audio output (or 2-channel PCM) - whether it be from the on-board apps or an external component connected directly to the TV/OCB.
No, this TV cannot output DD+ through ARC or optical.
No current TV - regardless of brand, make, or model - can output or pass-through lossless
, high bit rate
, HD Audio
formats through ARC or S/PDIF (optical or coax). It is simply a limitation of the technology.
(I have no idea why some people are actually surprised that these Samsung TVs cannot do it when no other TV brand can do it either. The use of an OCB on a Samsung TV doesn't change that fact - it only moves the ports from the back of the TV to an external box. Connecting a component to the OCB is the equivalent of connecting it to a port on the back of any other TV set. Note: The 4 HDMI ports on the OCB are input
ports, NOT output ports.)
S/PDIF (Sony/Philips Digital Interface Format) and ARC (Audio Return Channel) - which uses two pins from the HDMI connector, a previously unused pin and the hot plug detect pin, to transmit the audio "upstream" from the TV back to the AVR or Soundbar - simply do not have enough available bandwidth to transmit those extra audio channels or HBR (High Bit Rate) audio codecs.
(Note: The term codec
refers to the algorithm used to encode the audio. "Codec" is short for coder-decoder.)
There are a few select TVs out there (some Vizios for instance) who are
able to transmit DD+
(Dolby Digital Plus) over ARC. DD+ can
carry up to 7.1 channels, as well as a compressed
form of Dolby Atmos object based audio, from the TV apps. However, it is a lossy
, low bit rate, audio format - it is NOT lossless
One reason most TVs (e.g. Samsung TVs) can't output DD+ is because they were built with "chips" that allow for just one audio output, and that audio is sent to both S/PDIF and
ARC at the same time. Therefore, DD+ content is downgraded to 5.1 DD (or in some cases, 2-channel stereo) before being sent out through ARC.
Again, it is NOT possible to send lossless, high bit rate, HD Audio formats through ARC or S/PDIF (optical or coax). It is simply a limitation of the technology. Let me also point out that NO "on-board" TV streaming app support these lossless
audio formats anyways.
You should set your TV setting to "Bitstream" [see LINK below].
>Bitstream vs. PCM