5.1 Channel Signaling And HDMI Audio Extraction 18Nov23-12Dec23

Discrete 5.1 Channel Audio Extraction Trials: Excruciating... In the NestMT I want to use not only Dolby center channel & L/R surround signaling derived from stereo PCM via Dolby PLIIx, but also get discrete LPCM or 5.1 Dolby Digital to the speakers. Of my 3 main audio sources: Roku, JRiver, and vinyl, only Roku spits out true Dolby Digital; I turn the other streams into 2 ch PCM. Were I to use an AppleTV box, they prefer 6 channel LPCM. I want to extract the full unadulterated 5.1 digital signal directly from the Roku Ultra HDMI out while not disturbing the 4K/120Hz - UHD/HDR on HDMI bound for the TV. Almost all "extractors" only do 4K @ 60Hz and many just feign doing true DD 5.1 or DTS on the SPDIF optical out port, they just copy some channels to others. My TV is a capable 4K/120Hz/HDR monitor, as is the Roku Ultra, and I now access content at these levels often too ~ de-resolving or de-ranging is not in the cards (see ELSEWHERE on the blog to understand HD, UHD, and most importantly HDR). UHD/HDR pass through and full 5.1 digital audio extraction is an under-served need in the audiophile realm.

Rounds 1 & 2... I did find two boxes with the needed specs: the EZCOO AudioExtractor and the OREI 8K; both claimed 48Gbps (HDMI 2.1) bandwidth, real Dolby Digital 5.1 audio extraction, and the 4K/120Hz/HDR video pass through I sought. I bought some newer HDMI 2.1 cables to assure needed quality and bandwidth. Testing of the EZCOO failed badly and I returned it same day ~ it couldn't even pass through the HDMI properly. Fortunately testing of the OREI showed it capable of passing 4K/HDR @ 120Hz. I didn't test the audio extraction till arriving in Summit. I am out of luck for discrete DD 5.1 for the time being ~ while it did the video well, the only audio I could get from the OREI was stereo PCM, and I tried many HDMI sources. I returned it too. I went back to a derived center channel using PLIIx in the Dolby box.

Round 3... I still can't find an extractor with HDMI 2.1 support, sufficient fidelity, and operation which meets spec. So, I decoupled the HDMI pass thru task from the audio extraction task ~ I acquired a well-regarded high end HDMI splitter from HD Fury named Arcana 2. It does all the ARC/eARC stuff as well as even HDMI 2.1 @ 8K (for me 4K @ 144Hz with HDR is great). This splitter allows two different HDMI resolutions to be used while many splitters just drop all HDMI outs to the lesser spec connection. It's from the UK and more expensive but I tested it and HDMI passing was good. Plus it is super flexible in locking in the best modes on installation. However, while I got some stuff to work I could not get full 6 channel (5.1) audio from either HDMI port on the Arcana box ~ the UI even indicated it wasn't happening. Further, while a full HDMI pass through occurred, the TV would flash on occasion when labels and tickers appeared on the screen. Sometimes the Arcana wouldn't even re-sync to full UHD/HDR after the banners had passed. Lame; it was returned too.

Round 4... Undeterred but eyes open to the dearth of gear capable of meeting my specs, I continue to pursue the 2 separated tasks (HDMI pass through & audio extraction) idea to get discrete audio. I bought a gofanco Prophecy HDMI splitter. I'd split the HDMI from the Roku Ultra and send one out to the TV and the other out to a simpler extractor that I already have for extracting audio for measurements, and which I know works. An issue with my design in general is that I do still need regular 2 ch PCM for the main L&R speakers as the miniDSP DDRC22D accepts only that. Somehow from the Roku Ultra HDMI signal I need one optical pipe to carry 2 ch PCM for the mains and one optical pipe to carry DD 5.1 (or LPCM 6) for the center and surrounds. So, I will get 5.1 ch on optical from the extractor and 2 ch on optical from the TV. Well shit, the gofanco splitter didn't work either ~ HDMI pass through never really synchronized from Ultra to TV. The screen often went black and this was independent of using multiple sources and settings and even displays. I'm SOL again.

Round 5 - Final... Well enough of this BS, I decided to just acquire a newish, but cheapish/low power, AVR to do some of this, a Denon S570B. I'll use an alternative OREI splitter/extractor (the 102A) to get 5.1 DD on optical to the Dolby box for the center channel and 2 ch PCM on optical for the main L/R channels (minDSP) via a 2nd extractor on the 2nd HDMI out. The Denon also gets digital COAX back in from the Felston for Phono/ADC path and the JRiver streamer path. Testing in COS confirmed most operations; the new OREI S102 showed the most stable UHD/HDR pass through of the five gadgets I tested and it reliably extracted DD 5.1 audio for its optical port, when that existed in the source material from the Roku, and 2 ch PCM otherwise.

After pulling down the NOnkens I also gave the Denon AVR to Matt; I'll find a more inline scheme to get surround signalling from my existing Dolby DP564, but I may need to use it's AES3ID pro digital out ports and some interface conversion from that to SPDI/F for use with consumer DACs.