Sunday 29 December 2013

MEASUREMENTS: USB Cable Extension with Ethernet Cables - does it worsen jitter?

I mentioned in my "look at the sound room" post the other day that in the Emotiva XSP-1's multichannel "HT Bypass" mode, I'm dealing with some noise when the USB DAC (TEAC UD-501) is connected. In an attempt to fix the problem, I've tried a number of ways to minimize the problem - different USB ports on the motherboard, USB3 vs. USB2 ports, different USB cables, ferrite cores attached to the USB cables, even put in a USB3 PCI-E card... I've even dissected an old USB cable to disconnect the 5V line but it looks like the TEAC needs this present. All to no avail - the high pitched whine and buzz continued.

I then began looking at alternate options; here are a couple I found. The Firestone GreenKey looks interesting. I'm just not sure if it supports high-speed USB2 however which is important since the TEAC needs high speed for the 24/192+ PCM and DSD/DoP sample rates. There are other galvanic isolators like this one but they're just "full speed". Another option is with a better USB card like this Sonore SOtM PCI/PCI-E to USB which is often talked about on sites like Computer Audiophile. However, I really don't see myself spending $400 (with taxes and shipping) for a single port USB card; and I'm not even sure this will do the job I need! (Anyone with one of these cards can comment? A review like this one is useless for my purpose when there's really no discussion of whether they tried it in a noisy system and if it reduced audible background distortion.)

Hypothetically, I thought it might be interesting to try a different angle with this... Knowing that the ethernet system uses isolation transformers, what about the USB extenders using ethernet cables? Already, a cheap one was taken apart on Project Gus and it looks like these devices do indeed use standard LAN filters like the LFE8423. [My mistake, that link was for a USB-ethernet adaptor, not a USB extender like this one.]

With a quick search of eBay (here's a current auction), I decided to take a chance on one of these (also found listing on Amazon):
It includes a transmitter (computer end) and receiver (TEAC DAC end). The transmitter side will use the computer's 5V rail and a standard 5V power supply in the plastic bag is used on the DAC side - this of course isolates the power from the computer to the DAC. It also comes with a short USB A-A male cable for the USB connection from the computer to the "transmission" unit.
Notice the 5V power connector on the unit to the left for the receiving device end.
Total cost was ~$60 for the set including shipping from Asia. The unit is capable of 100m (~300ft) transmission distance and specifically rated up to the 480Mbps high speed spec. Unfortunately I don't see an easy way to crack open the little boxes to see what's inside and I figure I didn't want to risk breaking them at this point. Set up was easy and intuitive since there's barely any English in the instruction pamphlet. Plug 'n' play, no drivers to mess around with at all.

So... Did they work for my purpose? Yeah... To some extent.

They did definitely filter out the "computer noise". I can no longer hear the beeps and buzzes when the computer accesses the hard drive or when the CPU is busy processing. Unfortunately the high-pitched whine is still audible when I stand against the speakers; but much reduced - maybe 25% of previous and almost inaudible at my listening position about 9-10' away (ambient background noise is very low in my basement sound room). I tried different Cat5e and USB cables but this didn't make much different. The next time I go to the computer store, I'll see about getting Cat6a STP (Shielded Twisted Pair) cables and maybe shorter 3ft USBs to minimize any potential to pick up interference... I doubt this will make a difference however because I suspect the noise is embedded in the signal from the computer itself rather than picked up due to lack of shielding.

However, the opportunity presented in buying this item is that I can measure what happens to the DAC audio output through this USB signal conversion. If one believes that a digital cable makes a huge difference, then doing this should really create some nasty effects compared to having just a straight computer --> USB DAC cable. We could see diminution of dynamic range if doing this adds more noise to the DAC and furthermore, let's see if the dreaded jitter gets even worse! (Surely it must be awful, right?)


As usual, here's the setup used to measure the TEAC DAC output when I'm using the USB extender:

Win8 AMD A10 HTPC --> stock 3' USB (supplied in box) --> USB Extender Box --> 50 feet Cat5e cable --> USB Extender Box --> 6' Belkin Gold USB cable --> TEAC UD-501 DAC --> generic shielded RCA --> Emu 0404USB --> shielded generic USB --> measurement Win8 computer

For the direct USB situation, I used a 12' generic shielded USB cable (similar in build to the Belkin Gold USB cable) direct from the Win8 HTPC --> TEAC UD-501.

Notice how rather "unfair" this setup is for my needs... In real life I only use a 6' run of Cat5e cable, but to exacerbate any issues, I'm using a 50' run of just generic ethernet cable.



Here's the RightMark summary results. I tested 16/44, 24/96, and 24/192 for your consideration:

Notice how there's no difference whether it's a direct USB cable or the much more complicated USB-Cat5e extender setup. 16/44 as usual measures perfectly and there's not even a hint of loss in dynamic range, worsened noise, or excess distortion using the Cat5e hardware!

Frequency response at 24/192 (16/44 and 24/96 look to be exactly the same as well [not shown]):

Noise level at 16/44 and 24/96 (24/192 looks no different as well [not shown]):

No difference!

How about the dreaded jitter? As usual, let's fire up the spectrum analyzer and have a look at the Dunn J-Test output off the TEAC DAC.

Yet again - essentially no difference.


Okay, short and sweet - using a USB cable extender with a Cat5e system like this one does not degrade the audio output from the asynchronous TEAC UD-501 DAC. Even measured at a length of 50 feet (much more than my needs), there's no problem.

Subjectively I hear no degradation in the sonic output either and as noted above, it does reduce the noise with the analogue multichannel home theatre bypass on the Emotiva XSP-1 so it does seem to filter out some noise originating from the USB port... Not perfectly silent yet in my system but I'm slowly getting there :-). (This noise does not affect my stereo playback at all off the Squeezebox Transporter or TEAC UD-501, just when I listen to multichannel.)

I had a listen last night with some hi-res stereo 24/192 material - John Coltrane's Blue Train Classic Records 2001 HDAD, Neil Young Harvest off the 2002 DVD-A. Also had a listen to some DSD128 - samples from 2L's website. As usual they sounded very good off the TEAC. All the precision I had come to expect from the TEAC with standard USB cabling was there with no hint of resolution loss or evidence of digital error.

Basically, I'm stumped when I read comments on places like Audio Asylum by audiophile "audio engineer" folks who claim that even adding a ferrite core to a USB cable will do terrible things like worsen jitter (supposedly audible!). As far as I can tell, these folks also never seem to throw up a few measurements or describe what method they use to come to such a conclusion... Even if doing this worsened the sound quality, why do they blame jitter as the problem?

As far as I can tell, bits are bits; at least with a decent asynchronous DAC (I suppose there could be problems with old adaptive isochronous units). Asynchronous USB protocols like the one used with the TEAC work as they should to clean up any stray timing errors so long as the buffer isn't over run and the data is "bit perfect" (easily verifiable with a USB hard drive attached and looking for data corruption). Hard to imagine than anyone needs more than a decent (inexpensive) USB cable for quality sound if doing this kind of cable extension doesn't lead to sonic degradation. I do believe that there are many mysteries in this universe outside of the science we understand today, but digital reproduction in the audible spectrum doesn't need to be one of these! As usual, feel free to provide a link to some results if there's evidence to suggest I'm incorrect.

As we wind down the last days of 2013, I want to wish you all a Happy New Year. And of course a healthy and prosperous 2014 ahead...

Enjoy the tunes.

[2013/12/31 Update]

So, I headed off to the local computer store earlier this morning and bought some 50ft Cat6a STP (shielded) ethernet cables to try. I figure if this doesn't make a difference, the higher quality cable can be used for longer runs around the house.

Surprise! It worked... The whine is now gone. The analogue "HT Bypass" is still a bit noisier than straight balanced cable into the Emotiva XSP-1 preamp but at least there's absolutely no high-pitched noise audible with ears right up to the speakers now.

Again, subjectively, everything sounds great comparing straight USB to the USB-Ethernet extender through the TEAC DAC. Objectively, no evidence of deterioration and looks the same as previous results above:

At least for me, it looks like the use of one of these high-speed ethernet cable extenders is a good option to try for those suffering from USB-related noise in the audio system with no evidence of signal degradation (including jitter with an asynchronous DAC).

Happy New Year and stay safe with those late night parties! :-)

Wednesday 25 December 2013

MUSINGS: Those "next generation" game machines - PS4, XBOX One, Wii U...

Battlefield 4 - PC gaming time in the living room... Silverstone LC14 case in lower shelf. Arcade Street Fighter stick to the left. Old SNES still in the box to the right :-)
As I opened boxes and put things into place after the recent house move, I pondered about the living room situation.

I have a decent sized 46" LCD/LED TV there, my old Denon AVR-3802 receiver, the Squeezebox Touch, and a couple of old Tannoy MX2 bookshelf speakers. It's also where I will have the game machines - the good old XBOX 360 and Wii from a few years back mainly for the kids and the odd Kinect dancing game when friends come over :-).

Looking back, I basically grew up with computing technology... My first computer was the 5KB VIC-20, then Commodore 64, then Commodore Amiga before jumping over to the PC world in the mid-90's putting together my first PC in the venerable AT form factor. All along, games were the programs that truly utilized the computing power of the machines whether it was through hand-entering games published in the old Compute! magazine or being blown away when I first saw the "smooth" character and parallax animations in the Amiga game Shadow Of The Beast! Unless you're using the machine for frequent graphics rendering, or maybe folding, it's probably a safe bet to assume that it's the gaming software and the virtual worlds they create that will reveal the true power of the machine.

For video game machines, I think I've owned at least one representative from each generation. XBOX 360 & Wii, before that XBOX & PS2, before that PS1 & TurboGrafx-16/Duo & Panasonic 3DO FZ-1, before that Super NES, before that Atari 2600, before that Atari Pong (my dad got it as a novelty back in 1977 or so). But looking at the current offerings (a friend already has all 3 of these machines for me to try at his house!) - Playstation 4, XBOX One, and Wii U - I really have no desire to own any of these. I dunno, maybe I'm just getting old and tastes are changing... :-)

I suspect one thing that is changing for me since having kids a few years ago is just the time available for gaming (among other hobbies like audiophilia!). The push I see in this generation of gaming is that of extending the "social" experience. The opportunity to see what friends are doing, which games they're playing, sharing gameplay videos, and of course the ability to play online at the same time. I think that's cool and certainly for those who are looking for that experience, there's probably no better than the unified system that XBOX Live (which I used to subscribe to) and PlayStation Network have available (I've never tried Nintendo Network).

I don't know about you guys, but I'm feeling a bit of "Social Network Fatigue" (SNF) these days though... From the barrage of E-mails, phone texts, to FaceBook notifications, to LinkedIn, to Twitter tweets; I think I'm "good". Friends know how to contact me and I them... I'm not sure I need yet another network to join; especially one which is fee-based subscription and forces people to choose "sides" based on hardware preferences which is ultimately about securing financial revenue (isn't it always? here's a cute South Park take). Certainly you know this was what Microsoft must have been thinking when it first announced that the XBOX One had to be online for gameplay and also threatened to prevent the sale of used games early on. Thankfully, they later retracted this policy.

So, if we take a step back from the whole social gaming scene, what do we have left? The same thing as we've always had... Competing hardware platforms trying to provide the best interactive entertainment content either through inherent hardware superiority or exclusive games. And this is where I'm quite hesitant to buy in at this point.

For those who haven't read up on it, here are the technical stats: IGN Comparison and this from ExtremeTech.

In this generation, AMD's Radeon GCN rules in the graphics department. Every one of these machines is based on this internal graphics architecture which allows a much easier comparison of the graphical prowess. And in the graphics department, without dispute the PS4 is king. If one's priority is the potential to create the most detailed, smoothest gaming experience, then PS4 is the winner - especially that unified 8GB of GDDR5 RAM has thus far not been done and promises some amazing speed and texture quality. Already, with multiplatform 1st generation games like Battlefield 4, this has proven to be the case. Nintendo always seems to march to its own drummer and this is no different with the Wii U; it really cannot compete based on graphics hardware, and as always, must depend on first party titles (talk about proprietary hardware, the disc drive can't even play Blu-Ray movies for crying out loud!).

As for the CPU in these machines, it's very hard to get excited about those 8 AMD Jaguar cores in both the XBOX One and PS4 (the Wii U's PowerPC CPU a.k.a. Espresso is considerably weaker). Speculation is that already the OS is large with a couple of CPU cores unavailable for gaming use in both the PS4 and XBOX One. As to whether this might be a significant limiting factor to the gaming experience, I guess we'll just have to see (the Jaguar CPU core in Kabini is significantly slower than the Trinity core in the A10-5800 APU I've been running for about a year in my HTPC). Obviously offloading tasks to GPGPU streams can alleviate some of the CPU burden but it remains to be seen how this might also hinder the graphics horsepower.

Of course, currently we're only able to review first-generation games and as we have seen in previous console generations, things will only get better in time. With a specific target hardware, custom OS and APIs that can access abilities "closer to the metal", a lot of power can be squeezed out in optimizations. However, I suspect that since the XBOX One and PS4 are based on hardware already in existence in graphics cards for a couple years (GCN has been out since January 2012), the estimates of computing horsepower should be quite accurate and the familiar architecture will lead to optimizations sooner than something like what we saw for the PS3 and its unique "Cell" processor. Furthermore, I speculate that much of the programming optimizations probably will benefit across platforms due to these inherent hardware similarities, multi-core CPU optimizations should become standard for example.

As you can probably tell based on the tone of this post, I think I'm just going to wait on getting a game machine... Looking around here, I already have a number of pieces I can use... An old Silverstone Lascala LC14 case, 500W power supply, Blu-Ray SATA reader, XBOX 360 wireless controller receiver, nVidia GTX 570 from 2011 (still able to play a mean game of Battlefield 4 at 1080P)... On sale I got an AMD FX-8320 + 8G RAM + motherboard + HDD for <$350. Enough to put together a decent gaming rig for the living room which doubles as a general machine for fast NetFlix, streaming video playback off the NAS, etc. I've already got a few older games like StarCraft II, Battlefield 3 and Street Fighter IV which could be fun in the living room and maybe try out a few game downloads off Steam over the holidays. Heck, I might even go online to have a look (I think Battlefield 4 can handle up to 64-players). Another nice thing about PC gaming is compatibility with older titles numbering in the thousands; not to mention using emulators to run those old nostalgic ROMs I grew up to love (hey, my son loves Pacman). One thing I wish could be done easily would be to use the PS4's DualShock4 in a PC game machine; I love the feel of that controller. The Steam Controller looks interesting (probably released in 2014) - for now, I'm quite happy using the XBOX 360 remote controllers.

No matter what, merry Christmas everyone! I wish you all the warmth of friendships and family. To you gamers, I hope you find something you love under the tree on Christmas morn especially if you've been good boys and girls over the last 7+ years waiting for the next generation of consoles...

Till next time... Enjoy the tunes and games :-).

[Update Dec. 29, 2013]: I just watched the documentary Indie Game: The Movie. Wonderful snapshot into the world of independent gaming! I really enjoyed the quirky Super Meat Boy a couple years ago :-).

Friday 13 December 2013

MUSINGS: A Look At The Sound Room...

It's about 2 weeks now since I moved into the new home. As expected, it was stressful; with kids in tow, it's not like the bachelor days with just one's personal belonging in the trunk of my old hatchback!

Well, for the most part, the move hasn't been horrible. And the exciting thing as I've already previewed is that I now have a good sized "man-cave" for my A/V "needs" :-). Without further ado, let me show you the setup so far:
Head on view of the main system - Transporter playing.
Angled from the side - note the SUB1 just lateral to the left front speaker. The black box closest to edge of the sofa is the computer (Fractal Design Define XL case - nice and quiet).
"Super deformed" wide angle view of the room... Rear Paradigm Studio 80s visible.
As a MUSINGS post, I'm just going to spend a few words on thoughts around building the setup. Since the start of this blog and explored briefly in this early post, I do believe that judging the quality of an audio component can be accomplished objectively; that is, there is a technically "good" or "bad" way to know whether components live up to engineered goals. As I mused in that post, the gold standard for me is not so much to reproduce the "concert experience" as some might desire, but rather the ability of the equipment to reproduce exactly what's on the CD/DVD/DVD-A/SACD/Blu-Ray - that is my definition of high-fidelity. If the CD has an ability to transport me to a faraway concert hall, then I want my equipment to be able to reproduce that encoded sensory stimulus which leads to (hopefully) my ability to experience the same. Of course, not all CD/DVD/DVD-A/SACD/Blu-Ray's can do this! The medium itself must be able to encode quality to the extent that the experience is possible and the experience itself is provided by the artist, recording engineer, mixer, mastering engineer, producer, etc... who have put their expertise and knowledge into the recording. On my (consumer) end, I'm just looking for a good enough combination of components that can take that encoded sensory experience and provide it accurately; nothing more. I do not personally believe in aiming for a "euphonic" setup where the components can make all albums sound "sweet". I'm interested in just an honest presentation of what is on the disk; if I want to add euphonia, I will happily do it myself such as the PCM-to-DSD upsampling process or re-EQ with my Behringer DEQ2496.

As with anything in life, unless I were a billionaire, there are practical limitations on how much I am willing and able to spend on a sound system. I'm happy to sink money into the pursuit but it's only one of many interests! To spend as little as reasonably possible to achieve the best sound quality (and within decent aesthetic parameters) is a virtue I strive for. My experience has been that for electronics gear, there really is very little correlation between price and the (objective) sound quality it buys. For example, there's generally very little if any audible difference between a $500 DAC compared to a $2000 DAC if they measure the same; speakers, room acoustics, amps will easily trump the sonic differences. I can enjoy the inexpensive AUNE X1 (<$200) just as much as the more expensive TEAC UD-501 (~$800) even though I know the TEAC measures significantly better. In fact, I prefer the AUNE's more powerful headphone amp when I'm listening with the AKG Q701 headphones. However, the TEAC offers native DSD playback which is the niche it fills in my system. Likewise, the Transporter is my hi-res ethernet streamer, and the ASUS Essence One lives on my desktop for computer listening on account of its separate headphone/speaker controls and beefy headphone power. Where cost does seem to correlate better IMO is with the transducer devices - headphones and speakers. For these components, I'm quite happy to sink $$$ down! For fun, here's approximately how I've allocated out the cost of the audio system (minus HTPC which is more powerful than I really need for audio purposes). Note that I did not sit down to calculate this out before hand, it just organically came to be:

Speakers (fronts, rears, center, sub): 77.5%
Digital sources (including Behringer DEQ2496 processor, Panasonic Blu-Ray): 10%
Amplifiers (including Onkyo receiver): 10.9%
Cables + Belkin PF60 power console: 2%

Alright, I'm pretty happy with those numbers - I think they reflect reasonably well my priorities. Of course, the cost that truly trumps everything is the cost of real estate in Vancouver! So, let's run over the components I have set up in the room and share a few thoughts... As usual, since this is a MUSINGS post, it's mainly an experiential discussion with opinions thrown in.

I. First, let's talk about the 2-channel signal path:

Most of my music is in stereo. Therefore good 2-channel reproduction is most important. Enough said.

Time and again, measurements of the ASUS Essence One, Transporter, and TEAC UD-501 have demonstrated the superiority of balanced cabling. Whether anyone can hear the difference of course is another issue. Balanced operation was the reason for the choice of the Emotive XSP-1 preamp as the heart of the 2-channel system. To maintain the balanced topology, I got a couple of Emotiva XPA-1L monoblock amplifiers - good price and with the option to switch over to 35W Class A bias if I want.

Squeezebox Transporter music server chain:
Win8 HTPC --> ethernet --> Transporter --> Emotiva XSP-1 preamp (crossover at 60Hz to feed SUB1 subwoofer) --> Emotiva XPA-1L monoblock --> Paradigm Signature S8 v.3

Computer audio PCM/DSD chain:
Win8 HTPC --> Belkin gold USB --> TEAC UD-501 DAC --> Emotiva XSP-1 preamp (crossover at 60Hz to feed SUB1 subwoofer) --> Emotiva XPA-1L monoblock --> Paradigm Signature S8 v.3

Although just "fast ethernet" (100Mbps) is all that's required for the Transporter, the house is wired for gigabit and I've used generic Cat-6 cables for the Transporter to the gigabit switch. I'm quite pleased that I can easily transfer >100MB/s between machines around the home. All balanced audio cables were inexpensive (but good build) Monoprice Premier XLR's from 3-6' in length. Over the months, I've used Monoprice cables to measure balanced output from my DACs and the results have been excellent, not unexpectedly.

In the same vein, speaker cables are Monoprice 12-guage "Enhanced Loud" (LOL!) OFC. Monoblock to front speakers only 4', center channel 6', rears at most 25'; cut to minimum lengths required. I bought a 100' spool for $30 and still have some left.

II. Multichannel signal path:

I love multichannel music! The realism achievable can be amazing and IMO anything that enhances the creative potential of artists can't be a bad thing. Remember that historically multichannel speaker configurations were being explored along side 2-channel stereo. 3-channel stereophonic sound was demonstrated by Bell back in 1933 and the right-center-left "3.0" arrangement was used in some of the earliest "Fantasound" systems for Disney's Fantasia when released back in 1940. Having a center speaker in a theater setting allows the anchoring of front-and-center sound which improves the imaging for those not sitting precisely in the "sweet spot". For music, likewise it helps especially for solo/vocal tracks. For example, the Analogue Productions' Nat "King" Cole SACDs like The Very Thought Of You presented in 3.0 sounds phenomenal with this arrangement with Nat sounding like he's right in front of you crooning.

More than 10 years ago, I built a discreet multichannel system based on my old Denon AVR-3802 receiver. However, I had to give up the 5.1 setup when my kids came 8 years back to make room. After many years in "pure stereo" wilderness, I'm glad to finally be back with a full 5.1 setup again! Here's how it's hooked up:

Win8 HTPC / Panasonic Blu-Ray --> Energy HDMI --> Onkyo TX-NR1009 (amplifies rears and center, up to 145Wpc 2-channel measured) --> unbalanced RCA --> Emotiva XSP-1 preamp (HT Bypass Mode with channel to SUB1) --> Emotiva XPA-1L monoblock --> Paradigm Signature S8 fronts

Center speaker = Paradigm Signature C3
Rear speakers = Paradigm Studio 80 v.2 (tonal balance complements the Signatures reasonably well)

As you can see, my rears are full range towers.  I'm aiming for speaker layout angles approximating the ITU-R BS.775-3 (08/2012) recommendation at the "sweet spot" position:

I suppose I have room for a full 7.1 surround setup with 2 extra speakers to either side using the Onkyo receiver... Another SUB1 for 5.2 or 7.2 would give insane bass! One of many projects for the future, I suppose. I am unaware of any music I want available in 7.1 at this time and I suspect a TV upgrade to something like 80" would be more likely.

III. Challenges...

In a moderately complex setup, it's not surprising to find some challenges along the way. The main thing I found was that for multichannel, the Home Theater Bypass setting on the XSP-1 was very sensitive to noise. I had to move the PC to the left side about a foot from the subwoofer and ~5' from the XSP-1 to get rid of RF noise picked up by the preamp. Also, I had to use a "cheater plug" for the LG 55" HDTV mounted against the wall to remove ground loop noise. This was the relatively easy stuff!

The most difficult noise issue I'm still dealing with now is the USB interface to the TEAC UD-501. If I have the USB cable connected, there's a high pitched whine emanating in HT Bypass mode. This does not appear to be a component ground loop issue but rather noise from the PC through the USB interface polluting the analogue pass-thru. This actually does not affect stereo playback from the TEAC, just when I'm in multi-channel mode with the XSP-1 passing through the front stereo and subwoofer channels. It's not an issue with the RCA cables since more expensive AudioQuest and Tributaries RCA cables make no difference compared to inexpensive Radio Shacks whether 3' or 6'. The simple solution for now is unplugging the USB cable to the TEAC DAC when I'm listening to multichannel. Trying other USB ports and hubs have so far not helped. I'll have to look at other options like the FireStone GreenKey "USB Isolator" or some other way to achieve galvanic isolation but maintain high-speed USB 2.0 for DSD and hi-res PCM playback.

Looking ahead, I still have to try out some frequency response measurements and subwoofer room correction with the Paradigm PBK-1 ("Perfect Bass Kit") I bought (only ~$120). I'm inspired by Mitch's experiments with Acourate so may look into that too... The room is still bare and resonant so things should also improve when the rug comes and in time, perhaps some acoustic paneling and bass traps. Not to mention some clean up and better cable management!

As is, subjectively the system sounds good despite the lack of room treatments... Of course, I am a little biased :-). The Signature S8 v.3's are the current top-of-the-line Paradigm floor standers. Good to see some positive recent reviews like this one from TONEAudio. Some might consider them too "clinical" but that's fine with me since surgical accuracy is what I'm after. A large company like Paradigm can leverage the economy of scale to maintain costs and has access to research facilities which IMO is important. The beryllium tweeters sound sweet and very realistic. The other night my wife jumped when she heard the sound of the glass shattering on Michael Jackson's Jam (surely a sign of high fidelity!). So far I've also been quite impressed with the SUB1 subwoofer. I'm easily measuring excellent levels around 20Hz. I'll post PBK-1 and REW graphs when I start doing the room measurements...

I've played around with the Class A/B vs. A settings on the Emotiva XPA-1L. Realistically I doubt I will need much beyond 30W of power through the efficient S8 speakers so I expect the amps will remain well within the 35W Class A limit (these are 250W monoblocks in A/B). So far, I cannot say I hear much of a difference although I have not specifically done any "serious" listening in Class A mode yet. It certainly does get quite warm (somewhat uncomfortable to touch) after an hour in Class A mode - as expected. Makes for decent space heaters through the holidays I guess :-).

Signature SUB1 clearly visible.
I thought I'd end off with a couple of recommendations for multichannel lovers; both of these titles are only available as DTS-CDs from the early 2000's. I've since ripped these disks and converted to 5.1 16/44 FLAC with the DTS plugin for foobar2000.

- Lyle Lovett - Joshua Judges Ruth (2002 DTS release): Folks, this is a great example of what a good multichannel mix sounds like. Lyle's voice is mostly centered up front, good use of surrounds for ambiance, some discreet vocals in the rear tastefully done. Great dynamic range of DR16. I've always enjoyed the track Church from this album (and used it as a test track for the old MP3 test). In the multichannel version, you literally feel immersed in the choir when they start singing! It's unfortunate that a proper DVD-A/SACD was not released for this album given how good this sounds (already in the DTS-CD incarnation, this album puts to shame many DVD-A and SACD multichannel releases).

- Alan Parsons - On Air (1996 DTS release): Hey, it's Alan Parsons who knows a thing or two about good sounding audio... Progressive rock was made for multichannel - especially so when conceived from the start for surround sound. Rear channels utilized aggressively on some tracks along with birds singing, and cool jet flyby special effects (check out the first track Blue Blue Sky). Again, a multichannel DVD-A/SACD release would have been phenomenal.

Until next time... Enjoy the tunes, wishing you and yours a wonderful Christmas & New Year season.

(BTW: I got my Nikon D800 back from Nikon Canada for repairs on an autofocus issue under warranty. Wow. The focus seems to be spot on and only minimal lens fine-tuning is required now. There was quite a stir online about poor left auto-focus point accuracy as well which seems to be much better now. If you have a D800 and are running into focus issues, check if Nikon can do a tune-up.)

Wednesday 20 November 2013

Getting There... (Early HT Room Setup)

Back from my overseas business trip late last week. It's going to be really busy since I'll be moving to the new house in 1 week. Massive amounts to pack up!

Nonetheless, I didn't want the movers to be involved with the audio system so over the weekend I moved all the components and put together the stereo setup in the home theater room to just have a little "taste". Here she is... (Unfortunately the image is a bit grainy. Resorted to the old Nikon D70 as my D800 developed some autofocus issues and needed repairs.)

Hmmm. Looks like I need to straightening the power/cable/ethernet outlet at the back there...

Room size is decent: 20' x 15' x 8'. The TV is a 55" LG 55LW5600 mounted on a strong wall mount - I might go for a 70" in the future. Components:

- SONY SCD-CE775 SACD/CDP I bought back in 2001
- Emotiva XSP-1 pre-amp
- 2x Emotiva XPA-1L monoblocks connected to XSP-1 with Monoprice XLRs - 35W Class-A bias, max 250W Class A/B
- Paradigm Signature SUB 1 subwoofer crossed over at 50Hz
- Cables: 4' 12G OFC Monoprice zip cord speaker cables, Radio Shack 3' RCA from CDP to preamp, stock power cables

I still don't have the sofa sectional in the room and room treatments, nor have I set up the SUB 1's programmable subwoofer room correction yet with PBK-1. Despite the bare room reflections, it sounds pretty decent still... Played my old Kind Of Blue SACD, Diana Krall's When I Look In Your Eyes, and Beck's Sea Change tonight. Really liking the subwoofer's punch on the Beck SACD. I'm an advocate for a good subwoofer... Good frequency response down to 20Hz is essential for hi-fidelity IMO.

Chat later... More boxes to pack tonight :-(.

Saturday 9 November 2013

GUEST REVIEW & MEASUREMENTS: The Quantum HDMI Squeezer + ULTRA Cable: A look at HDMI cables.

By Keaton I. Goulden-Eyre III, Esq.

With Archimago overseas, he implored that I take a few moments to contribute to this most obscene of blogs (sorry dear readers, "objective" and audio do not mix in my worldview based on experience, wisdom, and my ears). Recall that many months ago, I brought you the review of Dr. Frank's "Best-Coaxial-Digital" SPDIF cable. I remain steadfast in my opinion of that fantastic interconnect!

A reminder - the introductory price is still available until December 31st! At $4999.99, it is a steal.


The cellular phone rang - "How inconvenient!"

That was my initial thought the evening I heard about the cable being reviewed today. It happened in August as I was at my usual Las Vegas soirée with associates enjoying some Château Pétrus on my way to a Wolfgang Puck restaurant with a tender morsel of imported Wagyu in mind.

On the other end was Alfred Fitzgerald, LL.B. A member of my exclusive gentleman's club back home who could not wait to discuss an amazing audiophile find. Having had many deep conversations around our shared passion for audio reproduction, he knew that I would find his news intoxicating. He was correct.

It so happened that recently he was representing the interests of a client; Dr. Joseppi Maltzarelli, in the acquisition of a 30m yacht off the Florida Keys. He discovered that Dr. Maltzarelli was in fact a physicist who interned at CERN's Large Hadron Collider in 2005. His ground breaking theories on the vibrational qualities of quantum superstrings in the terahertz range drew applause but also envy from colleagues such that he decided to leave the "mainstream" physics community to become the chief scientific officer of a startup to leverage his theories and experience. The company: QuantaVibes Inc. based in Dushanbe, Tajikistan, aptly located just across the street from the Gurminj Musical Instrument Museum showcasing the history of stringed instruments.

Although the phone conversation was brief, I could not enjoy the succulent Kobe that night - lost in thought as I contemplated the potential of what I heard! I just had to call Dr. Maltzarelli upon my return home. I was almost unable to enjoy Céline Dion that evening!

After many E-mails and calls to QuantaVibes, I was finally able to track down Dr. Maltzarelli via satellite phone located somewhere off the coast of French Guyana in his yacht. It was a wonderful discussion; here is a good portion of our conversation:

ME: Good afternoon Dr. Maltzarelli. Thank you for taking my call.

JM: Absolutely Keaton, any friend of Mr. Fitzgerald's is a friend of mine. (Both laugh in approval.)

ME: I am curious my good fellow, whatever are you doing out at sea?

JM: The South Atlantic is beautiful this time of the year, my friend! I'm planning to sail down to Brazil and into Uruguay by the spring time where I will go inland to research the acoustic resonances of spiritual earthenware of the Amazonian peoples. Just a well deserved vacation after years of programming my supercomputer to calculate some Super Large Numbers involved in Superstring equations. The company is almost ready to ramp up production on what we believe will be the most significant HDMI audio upgrade in this generation - if not the most significant audio upgrade of all time!

ME: Amazing Joseppi. I'm perplexed however, how did a physicist of your calibre ever get involved in audio in the first place?

JM: You see, this is what happened. In 2005 when I was at CERN, I discovered that free-electron lasers were capable of inducing terahertz vibrations in the Superstring subequations as expressed using the derivative of the semiconductor Bloch equations. This caused quite a stir in the community because it meant that resonance effects created by this perturbation in high order space-time could fold down into our 3 spatial and single temporal dimensions! My colleagues were not able to handle this truth. They started a smear campaign decrying my theories and even went as far as to label me as mentally unstable!

ME: Terrible! Such close mindedness - they probably still believe the earth is flat! Was this why you left CERN?

JM: Yes, amico. I could not tolerate this final insult and left to pursue other avenues to realize the profound implications of this research. As to the second part of your question; audio was a natural fit for these equations. Like the strings of a violin, the Superstrings resonate in a natural harmonic. It just so happens that these harmonics precisely overlap with the audio spectrum when free-electron laser spectroscopy is activated at odd harmonic multiples. As a result, we can precisely tame the stray frequencies and decouple the thermionic energy flux passed across various equipment. My research pin pointed to the HDMI interface as one which could use this "taming" effect as a first foray into audio reproduction for the company.

ME: So, is it something to do with the HDMI interface's complexity?

JM: Precisely Keaton. You see, HDMI transports "bits" like how the Transporter in Star Trek transports matter. HDMI communicates using TMDS which sends those bits and nibbles with no respect for timing or integrity. This just shreds the musical information apart and artificially reproduces it at the other end! No wonder people experience horrific digititis, headaches, gout, sarcoidosis, gastrointestinal problems, and other forms of neurasthenia with this wretched interface for music. Is it any wonder how jittery the HDMI interface is?

ME: Impressive, doctor. So what is this product soon to be released to combat the problem?

JM: Soon, we will be releasing the QuantaVibe Quantum HDMI Squeezer and accompanying QuantaVibe ULTRA HDMI Cable. They should be purchased as a pair for synergistic effect. The Squeezer consists of an adapter for regular HDMI to micro-HDMI because supercomputer simulations demonstrated that the smaller size of the micro-HDMI interface precisely corresponded to the wavelength of these Superstring terahertz vibrations. The increased density of electron flow through the micro-HDMI connector accentuates the resonant-transduction effect by 323%. We've treated this device with a patent pending ultramicrochip which precisely aligns the resonances. Unfortunately this is a trade secret so I cannot elaborate any further.

ME: And how about the ULTRA Cable?

JM: We understand if an audiophile wishes to use a standard size HDMI-A connector or cannot modify their system to accept the micro-HDMI. It is more convenient but no matter how I load my equations for the terahertz wavelength, it is still a compromise due to the size of that connector. Nonetheless, we will be selling separately our ULTRA Cable which has some of the technologies incorporated in the microweave of the insulator. Again, I cannot divulge any further information on the technology itself lest I get in trouble with the CEO of the company. (Both laugh.)

ME: You know Joseppi, many insane "objectivists" will be very critical of these worthy products. What do you have to say to potential critics?

JM: Keaton, my friend, there will always be "haters" in this world. I faced many back at CERN under the guise of "peer review" and still get many thumbs down with my Facebook posts and criticism with interviews like this one probably. I do not expect everyone to appreciate the benefits. In our extensive testing in the lab, only those with excellent hearing, trained ears, truly high-end equipment, and impeccable taste in music can fully enjoy what we are about to produce. Furthermore, we are so convinced that the discriminating audiophile will love this product that we will be offering a 35-day guaranteed satisfaction or full refund! Absolutely no risk! I do not believe anyone can beat that.

ME: I have never heard of this kind of offer - 35 days! Now how about sending a set to me for a review?

JM: Absolutely, sir. I will have my people contact yours. I apologize Keaton, I have to go now, the fidanzata is calling... Never let the fidanzata wait...

ME: I absolutely understand. I look forward to the review sample and our next opportunity to converse. Perhaps at an audio show? I hope you find some hidden truths in the spiritual earthenware of the indigenous Amazonians.

With that, and good to his word, a package arrived from Tajikistan two weeks later. Neatly secured in its own black silk pouch I found this set of adapter and HDMI interconnect:

The workmanship was excellent. Black which matches my custom-designed HDMI DAC (connectors personally soldered by Nodko-san in Japan) with fabulously gold plated connectors. Directionality was clearly marked on the cable (not shown). I was informed by an associate at QuantaVibes that these are prototypes and the production units will feature gold embossed lettering on aerospace-grade titanium in place of the white label shown above.

The Quantum Squeezer is a mere 6cm (2.5") in length but tucked within it the full package of Superstring optimizations. At perhaps 15 gm in weight it was ethereally light - befitting of the level of technology! The ULTRA Cable is 12' in length and should be long enough for essentially any connection between your source and the HDMI DAC. This cable was optimized for music so do not expect it to carry nonsense HDMI 1.4 extensions like 3D or even 1080P to some sources*. Wow! Mind boggling how the potency of these optimizations were capable of limiting video transmission in the service of audio.

"Ultimate Smooth"
I immediately connected up the Quantum Squeezer and ULTRA Cable to the HDMI input of my UltraBook computer and custom DAC for a listen. (Remember, the Quantum Squeezer only works with the micro-HDMI port common on newer portable computers like laptops/ultrabooks.)

I don't know how Dr. Maltzarelli did it, but he did! I swear, the Herbert von Karajan & Berliner Philharmoniker Beethoven Symphonies played in my soundroom from my 16-driver 863 pound custom speakers with GIA FL grade diamond tweeters driven by special edition Nodko 8-Watt SET tube amps with a sparkle and clarity I had not thought possible. The strings were smooth like a well aged Highland single malt scotch whiskey or the hum of my newly acquired Jaguar F-Type V8 S. The timbre of each instrument resonated with a "note" beyond the vocabulary of the best Wine Spectator writer. This was the power of Superstring audio optimization!

The beautiful multi-layered vocals from Stephen Layton & Britten Sinfonia's version of Chorus: For Unto Us A Child Is Born (off "Handel's Messiah", 2009) almost dislodged me from my seat with the immensity of the recording venue's soundstage (St. John's, Smith Square, London). I had never heard the numerous voices with such definition. I could make out the fact that the tenor in the second row secretly picked his nostril at 1:23 into the track. Replacing the QuantaVibes cables with my AudioSearch Whiskey HDMIs ($300/3') demonstrated just how superior the QuantaVibes were and stepping down again to generic HDMIs ($20) resulted in either a collapse or dissolution of soundstage, leaving the voices decapitated, floating in space in one instance and the next congealed in an incomprehensible mess as if lying supine in a morgue. The joy was gone, the textures made bland, soulless. It was so obvious that anyone who could not tell the difference must be auditorily blind.

The same effect could be found with more pedestrian music. Consider the sitar on the Beatle's Norweigian Woods (off the 24-bit remaster of course). On the vast majority of HDMI cables (including very expensive ones I might add), they sound shrill, overly trebly, and ethnic. Through the Quantum Squeezer and ULTRA Cable, this instrument played with its full glory demonstrating George Harrison's connection with the numinous (perhaps aided by various hallucinogens?), altogether natural, at One, familiar. This level of sonic reproduction is priceless!

Finally, my luscious wife Candy wanted to participate in the audition.We cued up her favorite track from the Spice Girls - If You Wanna Have Some Fun. The soundstage exploded beyond the walls side-to-side, front-to-back; and the vocalization from the Girls were lined up beside each other - you could even discern the relative heights of these women! Candy squealed in delight exclaiming "I ain't heard it go so low before, Big Daddy!" Indeed, we had fun.

Readers, let me be perfectly clear about this. Forget all you have heard about "holographic" sound from inferior equipment. These cables offer HOLODECK sound. Miles Davis' spit could be heard and visualized dripping off his trumpet, Coltrane's sax keys rattled before my eyes, Elvis' hips gyrated in concert with his live performances, and Michael Jackson's lewd gestures beckoned beyond the grave off Thriller! Dare I say, this is the first time I have experienced digital sound even begin to achieve parity with my vinyl collection. Such was the presence. You know you want this.

Now, as per my agreement with Archimago, measurements are a pre-requisite for reviews of such gear on his blog (again, absurd). I lent him the QuantaVibes HDMI Squeezer and ULTRA Cable for a couple nights just before he went off on the plane. I'll be back in a moment after this unnecessary interlude...

Objective Analysis:

Okay, as Keaton said, I had the chance to measure his review cable with a couple other HDMI cables using the following setup just before I leave:

AMD A10-5800K HTPC with HDMI-A connector or ASUS Taichi with HDMI-D (micro-HDMI) --> Test HDMI cable --> Onkyo TX-NR1009 --> shielded RCA --> E-MU 0404USB --> shielded USB --> Win8 laptop for analysis

Cables tested:
1. HDMI "high speed" cable, ION branded, 6' long, used in my previous Onkyo DAC measurements. No problem with HDMI 1.4 functionality like 3D to HDTV. Cost - about $20.

2. Fancy 4m (~13') Energy branded HDMI with all the check boxes ticked for HDMI 1.4a. It's touted as the "Connoisseur" Series which I'm sure Keaton would approve of. High speed to "13.8Gbps" specified, ARC, 3D, ethernet, 4K... Even has a tag as seen in the picture with "Confirmation of HDMI ATC Testing" - ATC in this case means "Authorized Test Center" and for this cable, the center was "Dat Tran". Nice metal connectors and general cable build quality.

At $50, this is probably the most expensive cable I have and will be used between the Onkyo receiver and LG 3DTV in my new setup. Note that the upcoming HDMI 2.0 standard specifies data transfer rates up to 18Gbps but is backward compatible with high-speed cables so I hope this cable will do the job in the years ahead.

3. The review QuantaVibes Quantum HDMI Squeezer + ULTRA HDMI Cable. The HDMI Squeezer looks like a standard HDMI-A female to HDMI-D male converter capable of a 90-degree rotation. Although said to be "heavily modified", I do believe similar adapters can be found at the local Radio Shack :-).

The ULTRA Cable is "standard speed" - tested to be OK with 1080P with my TV and the ASUS Taichi ultrabook, but NOT fast enough for 3D video off my Panasonic BMP-TD220 Blu-ray player.

Starting with the usual RightMark measurements, here's the summary (all done at 24/96, HDMI WASAPI driver):

Frequency Response

Noise level
No difference folks! Frequency response, noise level, distortion levels appear indifferent to the HDMI cables used.
Let's look at jitter with the usual Dunn J-Test:

Hmmm, what's this? The QuantaVibes spectrum is more jittery - especially noticeable with the 24-bit condition. However, notice what's happening here. Both the ION and Energy cables are being measured off the standard HDMI connector whereas the QuantaVibes is off the ASUS Taichi laptop's micro-HDMI port. What happens if we use the "HDMI Squeezer" converter but with the fancy Energy HDMI cable instead?

Voilà, the jitter spectrum now looks like the one above with the QuantaVibes ULTRA HDMI cable. Basically what is demonstrated here is exactly what I saw with the TosLink, USB, and coaxial digital interfaces. The jitter spectrum is a function of the sending and receiving device. The cable itself does not change the pattern; in this case, the little ASUS Taichi ultrabook tends to show more jitter than the HTPC AMD A10-based computer. Whatever HDMI cable is used does not change the jitter pattern (although I suppose one could wonder whether the HDMI-A to micro-HDMI adapter has an effect; not likely).

Bottom line from the objective side: No evidence that HDMI cables make any difference to standard measures of frequency response, distortion, noise floor/dynamic range of the DAC (Onkyo TX-NR1009 in this case). Jitter remains a function of the active devices, not a property that varies with the passive cables themselves (at least within the reasonable lengths tested up to ~13 feet). I'm happy to be proven wrong if anyone else has good data especially with less jittery DACs than this receiver.

I am therefore at a loss as to Keaton's enthusiasm around this product.

Back to Keaton for his conclusions.

Keaton's Konclusions:

Bollocks, more squiggles from Archimago... Yet again, measurements remain insensitive and unable to achieve the resolution of my 73-year young experienced ears. Hence useless and invalid for audio evaluation. We all know that everything matters, even more so digital cables because there isn't such thing as digital according to these enlightened gentlemen. HDMI is of course the worst of all the digital connections for audio (some other enlightened gentlemen at Audio Asylum agree) which makes it so much more important that we spend more money on ensuring perfect digital transmission.

As a side note, I connected the ULTRA HDMI Cable by itself to my Blu-ray player and 85" 4K TV. I swear, the image was more stable, colors brighter, and the actors moved so smoothly and with such poise that B-movies seemed Oscar worthy. Likewise, the audio-video synchronization was even better with these cables that I wondered how I managed to watch movies without them! Here again, the power of jitter-free sympathetic Superstring resonance at work. Indeed, I will be ordering a separate set of ULTRA's just for the Blu-ray player when the final product is released. Nonetheless, I feel that without the HDMI Squeezer, the synergism just wasn't there. The sound didn't reach as deep, the trebles didn't quite touch the heavens; without doubt, you need the full set!

You likely are aware that so far I have not said how much these high-tech devices will be sold for. I was told the company is still perfecting the quality control due to the precise manufacturing standards and complexity of the patent pending process. Expectations are that both the HDMI Squeezer and ULTRA Cable will be priced as a set at the $3000 mark. By itself, the ULTRA Cable will be around $2000. Mere pocket-change for this level of sonic/video revelation - I bet your power cords costs about just as much and they only have 3 individual wire lengths inside at most, and require less precise shielding! This is very comparable to other high-end HDMI cables such as these or these or these especially given the improvements on the quantum scale!

With this premier product from QuantaVibes, I am confident that we will 'hear' more from this up-and-coming newcomer to the high fidelity audio scene. I have a strong feeling that Dr. Maltzarelli's research into Amazonian earthenware will yield many revelations into audio resonances for upgrading the sound room. It was with supreme regret that I had to return the review cable back to QuantaVibes after 3 weeks of audio bliss for fear of industrial espionage. Currently awaiting their formal release with bated breath and ample liquidity in hand.

Until next time; Magico wishes and Burmester dreams.


* This cable is rated as "Standard HDMI".

Ed: And so ends the digital audio cable measurement quadrilogy. That is, until yet another digital audio interface shows up with fancy cable claims... Enjoy the music till then :-).

Saturday 26 October 2013

MEASUREMENTS: ONKYO TX-NR1009 as HDMI / SPDIF DAC... Are AV Receivers any good?

The rat's nest.

Running separate components like multichannel processors/preamps to monoblock amplifiers are generally considered the ideal, "cost no object" approach to home theater. In the real world, cost and space are considerations and AV receivers become the "Jack-of-all trades" central device that most of us have in the home theater setup. But like the proverbial "Jack", it's useful to also consider the second part of that saying... Just how bad  is he also "the master of none"?

In the last installment, we looked at passing an analogue audio signal through the Onkyo and found that noise can be an issue. Today, I want to demonstrate the quality if we were to just use this device as a DAC - a look at the digital portion. Some natural questions arise - how well did the designers shield noise from getting in (especially in light of the high analogue noise measured previously)? Is the jitter through the use of HDMI "bad" (compared to TosLink and coaxial S/PDIF)? How does it compare to other stereo DACs?

Based on the Onkyo specs sheet, the TX-NR1009 uses the TI PCM1690 6-channel + PCM1789 2-channel DAC chips. Both are rated as 113dB SNR. These DAC chips are often found in consumer AV receivers and are lower spec'ed than most stand-alone DACs like the TEAC UD-501's PCM1795 with >120dB SNR. Of course, you cannot just look at this specification and judge the quality of a DAC. Much depends on the analogue circuitry around that DAC so the measured results are more useful than just looking at the components individually.


As usual, for the sake of full disclosure and opportunity to repeat/verify, here is the setup for these measurements:

Win8 AMD A10 "Trinity" HTPC --> HDMI/TosLink/coaxial cable --> ONKYO TN-NR1009 front stereo "pre-out" --> shielded RCA --> E-MU 0404USB --> shielded USB --> Win8 laptop
CM6631A device used for asynchronous USB --> coaxial / TosLink conversion duties.

HDMI driver: default AMD WASAPI. I used JRiver for playback.

Since I want to check the performance in a more "naturalistic" fashion, I made sure the TV was connected and on as well as my Blu-ray player (Panasonic BMP-TD220). Remember that in my previous post, plugging in the HDMI TV cable added significant noise to the analogue pass-through. All results were made with the Onkyo in "Pure Audio" mode to defeat any audio DSP/bass management.

HDMI cable: A decent looking 6' length capable of high speed HDMI (officially rated as HDMI 1.3 but fine with my HDMI 1.4 3D TV), brand named "ION" that I purchased for something like $20 about 2 years back at a local computer/supplies store.

TosLink and coaxial SPDIF cables I'll be using for comparison are the "Acoustic Research" branded 6' lengths I measured previously (see links for details).


As usual, I ran the output through my digital oscilloscope first to have a look:
Here is a 0dBFS 1kHz square wave sent through the HDMI and measured off the front stereo "pre-out" RCAs. Not bad - good square waveforms with excellent channel balance (sorry about the pixellation, usually screenshot looks better than that). With the receiver volume set to the "reference" of 85 (there is a little popup on the front screen when you hit 85 that correlates to the 0dB THX reference level) and in "Pure Audio" mode, the peak voltage is around 2.3V.

Here's a 24/44 impulse response:
Good linear phase impulse response, nothing fancy here. Absolute polarity also maintained by the Onkyo.

I. RightMark:
As usual, I used RightMark to look at the measured dynamic range, noise level, distortion levels; here's the summary for HDMI at the various bit depths and sample rates:

As you can see, I've also included for comparison the results at 24/96 for the Squeezebox Transporter and TEAC UD-501 (unbalanced outputs) - two of the best measuring DACs I've tested here with the same hardware/software.

Clearly the Onkyo is capable of hi-res with >16-bit dynamic range. With 24-bit data, it can do ~109dB dynamic range which equates to just over 18-bits! Not as good as the dedicated audio units like the Transporter or TEAC but pretty darn good for an AV receiver! This result is about equivalent to the AUNE X1 and ASUS Essence One using unbalanced RCA output - however, those DACs had better distortion numbers.

Some graphs to review from the 24/96 dataset:
Frequency Response
Noise Level

The Onkyo rolls off a bit more in the high end, a little more noisy, and notably more harmonic distortion.

For fun, here's the spectrum off the Onkyo playing 24/192:
Yup, capable of 24/192 although the roll-off on the high end is obviously earlier than the TEAC UD-501 (Onkyo drops -3dB at 50kHz).

I was curious if the SPDIF (TosLink and coaxial) inputs measured just as well:

Yup. They all look pretty good. The graphs all look identical except for slightly more high end roll-off with the HDMI interface compared to the SPDIFs - not sure why.

With the dynamic range >16-bits, this test should be no problem for the Onkyo (HDMI input).

That looks very nice given that many very expensive DACs are not even capable of this degree of resolution! Again, this is an AV receiver! As I previously posted, even recently released DACs like the Wadia 121 Decoding Computer is incapable of this resolution.

III. J-Test for Jitter
As usual for my DAC tests, let's have a look at the Dunn J-Test spectra for both 16-bit and 24-bit signals. Here is the summary using the 3 digital inputs - HDMI, coaxial SPDIF, and TosLink SPDIF:

As you can see, the Onkyo is quite jittery in general whether HDMI or the other SPDIF interfaces. Although quite similar, I am somewhat surprised that the sidebands were more pronounced for the coaxial digital input! For comparison, here's the Transporter and TEAC:

Although the scale and dimensions are a little different, one can certainly appreciate just how jittery the Onkyo is compared to the others especially with the 24-bit signal. From this data, we see that the Onkyo itself has more jitter as a whole; specifically it's not any worse with the HDMI interface. We'll talk about jitter again in a little bit...

IV. Does sending a 5.1 channel signal degrade the measured performance?
I thought this would be interesting to check out. I left the RightMark test signal as the two front channels and added some AC/DC "Thunderstruck" into the center, rear, and LFE channels played back in JRiver as a multichannel FLAC through HDMI.

Beautiful ain't it?! The idea is to see if driving 6 channels (5.1) at the same time through the HDMI cable into the Onkyo's DAC will change the audio quality... For example, doing this might increase the noise floor, or perhaps worsen channel crosstalk since we've tripled the number of audio channels being processed.

Frequency Response

Noise Level
As you can see, there's very little difference whether 2 channels are playing or 6 channels. Great to see! Essentially no frequency response or crosstalk difference. However, there is a very small increase in noise level when playing multichannel... IMO audibly insignificant but measurable.


Here you go folks! That's how a higher-medium end "modern" AV receiver measures as a stereo DAC. Of course, each model will be a bit different, but I suspect similar tiered receivers from Pioneer, Denon, Integra, Yamaha, H/K, Anthem, etc... should be comparable (won't know unless someone tests it out). Note that most magazines like Sound & Vision will measure receivers but usually in the context of power output and flatness of frequency response rather than on the accuracy of the digital-to-analogue conversion as I did here.

In some ways I am impressed and in other ways the results were as expected.

I was impressed by the low noise and very good dynamic range for example. To achieve almost 110dB in the audible spectrum is quite something especially considering the complexity of an AV receiver with all the potential electrical noise sources inside the box! The accuracy of the 16-bit -90.3dB waveform looks excellent; something which only the better stereo DACs or CD players would have been able to accurately reproduce a decade back. Likewise, the fact that the measurements remained excellent even with 6 channels being processed concurrently and only measuring about 1dB difference in the noise floor again demonstrates the engineering quality. Given the results I found previously with HDMI noise polluting the analogue input, I'm guessing that Onkyo put more attention in optimizing the digital side which makes sense since most people will be connecting digital inputs for multichannel sound.

As for the more "expected" results, let's talk about jitter...

A few years ago in 2009 this message came over the 'Net which I remember made quite an impression on me around how "bad" HDMI is as an audio interface (supposedly from Hi-Fi News & Record Review / Miller Research):
(I didn't notice it at the time, but that Denon AVR-3803A was a typo - the 3803 has no HDMI. It's actually the 3808.)

Later, a more comprehensive message appeared:

Hmmm, it looks like HDMI jitter can be cleaned out after all (eg. Arcam, Classe, Pioneer)! It's about the implementation, not necessarily the interface itself. If you read around these posts, one also finds that the jitter value and subjective sound quality do not necessarily correlate.

Let's think about the J-Test and what was found in measuring the Onkyo for a moment. The Dunn J-Test is a synthetic test of data jitter first published by the late Julian Dunn around 1994 which (in the 24-bit 48kHz version) superimposes an undithered LSB 250Hz square wave over a primary 12kHz -3.01dBFS sine wave which is of course an exact 1/4 of the sampling rate. This superimposition stimulates the effect of subtle timing inaccuracies (jitter) which can be demonstrated as accentuation of the sidebands measured in the spectral graphs.

Remember that this test is synthetic and stimulative. What you see measured is not something you're probably ever going to "hear" in real music! The noise floor is not going to be down to the last bit in 16-bit audio and essentially impossible with recorded 24-bit audio (unless it's purely computer synthesized music). Also, jitter is more pronounced in the higher frequencies (11kHz and 12kHz are used as the primary signals in the J-Test). Realize that the human hearing sensitivity is well on its way down by 5kHz (as can be seen by the Fletcher-Munson Curves). Furthermore, if we specifically look at the Onkyo's J-test spectrum, the most pronounced side bands are about -90dB below the primary signal. To make matter even less worrisome is that the tall sidebands are all +/-250Hz around the primary signal and the audibility would be masked even if one did have awesome auditory acuity at 11/12kHz and could hear a signal 90dB down! This is also why I feel adding up all those sideband peaks and calling it a number (whatever picosecond or nanosecond) is really not all that useful when it comes to audibility.

What I'm trying to say is this... Tests like the J-test can demonstrate that jitter is a real phenomenon. Engineers should pay attention to it when designing hi-fi equipment. A discerning audiophile should be aware of it and if able to, can measure it themselves and decide if the engineer did a good enough job. However, IMO, to say that jitter is somehow audible at these kinds of levels I think would be impossible. In fact, unless the jitter were ridiculously high (like Track 26 from Stereophile Test CD 2, where an insanely simulated 10ns sideband is inserted +/-4KHz around the 11kHz primary - again totally synthetic), the concept of jitter significantly deteriorating sound quality I believe is utter nonsense in the real world. That some companies would even consider using jitter as a reason for putative significant audible differences between passive "components" like cables is just not credible!

I had a listen to the Onkyo's output over the last few nights with some familiar music - Ella Fitzgerald "Sings The George & Ira Gershwin Song Book", Grateful Dead "American Beauty", and Keb' Mo' "Just Like You". Also had a listen to Sting's new album "The Last Ship". They all sounded nicely rendered as they should with a good DAC. Great details with my older Paradigm Reference Studio 80 v2's which will be my rear speakers in the new sound room. The wife and I both enjoyed Sting's "The Night The Pugilist Learned How To Dance" - cute.

So, even though the AV receiver might be the "Jack-of-all-trades", at least in this specific instance with the Onkyo TX-NR1009 as an HDMI DAC, he might not be a "master" at it, but I'd say he's a pretty decent tradesman :-).

Well, unless I dig up something else to report, I'm likely "going dark" for the next month as I head off overseas for some work and then the big move to the new home. I'll be sure to post some pictures in time... Enjoy the music everyone!