I’ve been running the optical outputs from both my LG C7 OLED and CX77 OLED for a while now. The sound was always good — clean and clear — but when I introduced a Sony 4K Blu-ray player paired with an HDMI de-embedder, I realized maybe there was an opportunity to make movies sound better.
Playing a few Blu-ray discs through this setup and then comparing the exact same titles streamed on Netflix revealed a noticeable difference in sound quality. No surprise there — Blu-ray delivers uncompressed PCM, while Netflix doesn’t — but the gap was bigger than I expected.
Digging deeper, I realised one setting on the LG had been holding things back: audio delay. Switching it to bypass seems to improve the sound?
That led me to take the plunge and pick up a Blustream ARC11. I now feed audio from the LG’s ARC output into the ARC11, then send the optical output straight to my Chord DAC.
The result? The sound has taken on a darker character — mids have somehow improved the most and higher frequencies are calmer.
I’m not entirely sure why there is a difference ? It seems that the ARC 11 device is allowing me to enjoy better sound from my apple TV streamer. Or is just my imagination?
I did a few A/B tests with the Optical vs HDMI ARC it is quite hard indeed to discern a difference now… even with switching the A/V sync delays on the TV.
Maybe it is just my imagination after all.
But I won’t be selling the ARC 11 or using the LG optical output either, I just like it the sound going through the Blustream ARC 11.
The two TV’s I have, one LG OLED C4 from 2022 and one Samsung from 2015, the HDMI ARC outputs are 16/48 into my DAC.
The optical output on the LG is also at 16/48, however, the Samsung (which was top of the range in 2015) is 24/48.
I prefer to use the optical outputs from the TV’s for stereo into my DAC’s and use the HDMI ARC output on my main TV into my AV Amp for 5.1 sound for movies from Netflix and Amazon Prime.
Based on the specs of my TV’s and listening tests I don’t really hear any noticible sound quality difference for stereo into my DAC between optical and HDMI, but I think for stereo into a HiFi System the preference is to use optical, which is generally the most common connection into DACs rather than HDMI.
If linking a TV or playback device to home theatre I would always use HDMI as it supports high definition multichannel audio whereas optical doesn’t. However, if linking a TV to a stereo I would always opt for optical as it avoids any electrical connection between the two and therefore isolates the hifi from whatever ground plane noise profile the TV has.
So I think the answer on which is best is very much “it depends”.
Playing some old concert recordings with the Blustream ARC extractor, and also with Infuse software on the Apple TV as a source.
music appears to be more dynamic, engaging. Did some A/B with the Blustream and through the LG Oled.
There is a difference, the sound seems more engaging through the Blustream?
Both the Blustream and the LG have optical outputs to my Chord DAC. So whatever it causing this difference is due to software treatment of the HDMI audio stream from the apple TV