We snagged prime parking at Zuma and headed up @ 9° about 8:30 today. It was chilly for sure but the lack of wind and the warming from bright sun made it decent. We don't have rad terrain with the drought back weighing in but we do have a new lift open. We roamed all over the front two mountains and did take the Bergman above that bowl and Independence... great new runs will open soon; today it was mainly windswept teeth chattering stuff. Still, great to be up there.
We had a great day in Summit with special friends at dinner @ Bistro North and @ the Nest. Whoa... we all stayed up to welcome in 2024 and celebrated together. It was all great fun. We gathered at Bistro North with DD & Y, Steve & Donna, and Jim & Mary for an excellent meal highlighted by the scallop special appy and beef Wellington entree but everything was very good... mostly the comradery among a sharp team rarely assembled.
Preceding the bigger meet up though, while the ladies shopped, Jim & I made a lap of the tarn in the White River NF. We all then hit ORB to try the new French Alps beers. A fine start to the stellar day.
I've enjoyed designing and building custom speakers for the NestMT and have some additional "needs" I will fill with a new pair of DRC DIY speakers. They'll most likely adorn my study desk at the Nest so need to be small and great for close field listening. I've read about building spherical cabinets (few standing wave issues and significantly reduced diffraction interference) and have heard commercial (B&O) designs employing them as well. In fact, some DIY forums suggested that a build based on Ikea Blanda Matt bamboo bowls are effective and inexpensive! I bought four 8" bowls and gave it a try. In just 4 hrs I was enjoying HiFi sound with surprisingly good bass thumps.
Design choices beyond driver selection were very constrained given the cabinet is basically set from the get go... it's whatever two 8" salad bowls glued together will yield. That's 3.6 liters before adding the driver to a flat cut opening and 2.7 liters after removing that section. I sketched stuff and used modelers to help me choose bass reflex port dimensions given Theil/small parameters and the cabinet. The sealed cabinet variant performance would not have been good from initial modeling, so I went right to the ported style. I saw some Onken-like port mid-sections from other DIY builders but decided simpler & faster is warranted here.
I then used a hole saw to cut a hole in the "back" for my ~ 1" x 4" flared port. I also drilled for the banana plugs. The port was a good friction fit but I glued it in place anyway. It's not a great location for the port directly behind the driver but the off-axis nature of this particular driver added confidence it'd be fine. I like it there aesthetically to remove the bowls' original manufacturing indentations & markings. Once the holes were completed I sanded the lips of the bowls to allow better acceptance of the glue. We don't want the spheres to roll around so I added 2 ball feet (drawer pulls) to each cabinet while the 3rd point of rest on the surface is the cabinet itself, which was dotted with a silicon foot. I then glued and clamped the bowls together into cabinets.
Once dried, I stuffed 6 oz of poly fiber fill into the interior and wired up the drivers. I laid a sealing gasket around the drivers and secured them to the "fronts" carefully with black wood screws. All the hardware is silver/nickel to match the drivers' accents. Matt called them Googly Eyes.
December music appreciation highlights from me do not include holiday songs, despite Billie Eilish's appearance on SNL where she sang "Merry Little Christmas." Let's go...
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.
Hanging The NOnken Surrounds... In deploying the NOnkens to the left & right surrounds locations I needed secure permanent installation spots that were out of the way of walking about and very strong to carry the weight. I chose to hang them from the wall above heads and point them at the seating properly. I think even Bro Brown can walk under them. Note that the full NestMT image is distorted and the NOnkens appear strange due the focal length... the direct head on images of the hanging NOnkens shown later are more representative of the install.
The NOnkens are 35 pounds a piece and in investigating mounting hardware I was
immediately drawn to the pro PA stuff enabling suspension via a 35mm
cup/pipe system ~ these had 5X or more the carrying capacity of other
mounts and held up to 100# each. It's a widely used standard mounting
system in theaters, stages, and mobile kits and most PA speakers these
days have the cup built into the base. Enter the BiGalleons, adjustable
powder coated steel mounts affixed to the wall via 6 substantial anchor
bolts (which get covered up nicely). Each surround was outfitted on the
back with an external mounting fixture I fabricated... I used 1 1/4"
conduit (which had the proper ID to mate to the BiGalleons' "pin"), a
block of leftover Baltic birch, U bracket holders lined with old bike
tube rubber and a tapping screw (that goes into the hole to register the
speaker to the "pin"). I bought and returned manufactured external
mounts as they didn't allow the desired optimal mounting in the room ~
would've lowered the speaker and limited it's angling. My fixture screws
into the back of the DRC NOnken and I can angle appropriately and
install
the surround almost right at the ceiling level. My mount will be proud
from
the wall a bit more but that's fine. I checked my angles and my working
idea first, to assure all would fit OK, sure it was in ink :); 𝛼 =
51.3° and β = 54.5°. Installation went fine but I did needed quite a bit
more 12 gauge oxygen-free zip cord speaker wire (I eschew all those
expensive audiophile low loss cables for my own builds with banana
plugs); 12 gauge is pretty big but this is a long run.
Surround Signaling... I purchased a Denon S570B on Cyber Monday for a good price - Denon should do
audio well and they claim full 8K/UHD support, if I need that. It allows me to get
surround decodes (DD 5.1 or D PLIIx) and power (since I returned the Schiit amp) for the
surrounds. Why do I need decodes you might ask. Unfortunately, during
comprehensive testing of the used Dolby
DP564 I discovered that one of it's surround channel analog outputs
doesn't work. Investigations online indicate that this 20 year old gear
does tend to have this analog out failure mode ultimately. Therefore,
the Denon decoder will be used for the surrounds ~ same algorithms after all; fortunately it has
it's own time delay capability so I'll be able to dial that in cleanly
for the surrounds. Initial testing of the Denon and new surrounds went well... I'm delivering 2 ch PCM or 5.1 DD to the S570B via COAX Spdif (big orange) from the Felston. Optical from an HDMI audio extractor would work too.
Initial NestMT 5.1 Impressions... Holy soundfield! While I was wary of the final outcome, the new NOnken surrounds make the NestMT expansive; my mind is blown. The 6 high performance full range Fostex drivers in my custom back loaded horn and bass reflex Onken cabinets deliver the goods beyond reason ~ sure, they're augmented by Viawave/hi and Hsu/lo and even some signal processing but who cares if it sounds this cool. The recent expansion from 3.1 to 5.1 is ear-opening and unexpectedly good. The derived and direct surround sound from the Denon box is fine and clean. Listening is a blast however it is late so I will leave remeasuring and resetting delays for an update.
Measuring The NestMT 5.1... I rebuilt EQ in Dirac for the L/R mains (with Veriwave tweeter & Hsu sub) just for good measure ~ not much change. I then measured the center channel and surrounds and checked the impulse measurements to assure the delay is right between them. They are the about the same distance to my ears and fortunately not much tweaking is required. There is not much processing delay difference in the AVR for surrounds and in the DP564 for centers; what is needed can be done in the Denon AVR. I also remeasured the processing delays between mains and center/surrounds, which are handled in the Felston, for each source; they are again about the same as set prior for just the center. I won't bore you with the delay measurement graphs and settings... I'm just gonna provide the composite sweeps and their average. The "mains" graph includes the sub & supertweeter with the new Dirac EQ. The centers and the surrounds have no EQ applied and the surrounds are being measured off-axis of the mic. The new NestMT 5.1 system is amazing but I do note the 5dB baffle step shout from the surrounds 1KHz-4KHz and may want to address that with specific EQ.
The BOnken come NOnken saga made my move to 5.1 channels in the NestMT a tough road. The project to even hang the NOnkens, as described here, was very challenging, with its own hiccups along the path. It is worth it but I am glad it is almost over.
Update 31Dec24... I'm dissatisfied enough with the surround signaling (it was thin and odd derived from PCM 2 channel) AND the performance of the NOnken surrounds (described prior) that I have removed and decommissioned the speakers and have redeployed the drivers elsewhere for now. I will design something better from scratch and will seek better 5.1 signaling somehow. Matt will get the AVR and the surround hangers are very solid and will remain on the ready for reuse.
