MEASUREMENTS: Raspberry Pi 3 "Touch" music streamer

The music being played is the soundtrack from Japanese anime Your Name (Kimi No Na Wa). Saw it with the family last week - great flick!

A few weeks ago when I described the building of the Raspberry Pi 3-based music streamer with touchscreen (I'll just call it "Pi Touch" in this post), I promised that I was going to publish some measurement results.

Well... Let's have a look at those results! :-)

MUSINGS: On Being an Audiophile, Rationality, and Respectability (Thoughts on the Hardware Audiophile Hobby)

For the post today, I thought it would be interesting to take a step back from my usual measurements and various objective explorations and spend some time thinking about the "audiophile" hobby; you know - the big picture.

For some, the idea of "rational audiophilia" as suggested in the image above might sound oxymoronic. After all, anyone who spends thousands of dollars and hours upon hours of time on audio toys in an obsessional fashion is at the very least "neurotic" and somewhat irrational. One could spend his/her time working hard to make more money, spend time with family, read a good book, enjoy a play, take a vacation, go exercising... All of which depending on the situation potentially more worthwhile and healthier.

PREVIEW: Oppo Sonica DAC (Thanks Oppo for making it right... On the rationale for technical perfection.)

Usually, I don't post many "preview" type articles, preferring to give you guys "the goods" when I've had an adequate amount of time with a device (usually at least a month or so) including measurements and such. I'll discuss why I'm posting this earlier as we go along...

Well, this is what showed up at my door last week:

That's of course the recently released Oppo Sonica DAC. A "hi-fi" USB, S/PDIF, ethernet, WiFi, Bluetooth digital player with DLNA streaming capability, part of the Oppo Sonica "family" of audio devices. The only other device with this moniker currently being the Sonica Wi-Fi Speaker, capable of 24/192 streaming. Coming later this year apparently is the larger Sonica Grand.

Let's have a peek inside the box...

MEASUREMENTS: Windows 10 Creators Update USB Audio Class 2 Driver. (And a request of Neil Young / XStream.)

 

It has arrived... Finally... Microsoft's USB Audio Class 2 (UAC2) native Windows driver has been released with the recent Windows 10 Creators Update ("CU", version 1703, build 15063.138). I updated my home theater PC and when I plugged in my TEAC UD-501 DAC to the USB port (with no TEAC driver installed), Windows detected it and proceeded with the device set-up automatically.

Considering that Mac OS X and Linux have had "native" drivers for years, I guess it's about time that Microsoft finally got the job done. Remember, "UAC2" has been out since 2009 as an evolution of the "UAC1" standard from 1998.

Of course, this doesn't mean the Windows world has been deprived of high quality sound... Companies have been releasing their own drivers since the beginning.

RETRO-MEASURE: 2002 Lynx L22 PCI audio card in a ~2008 Intel Q6600 Computer. (On "computers are noisy!" for audio)

As many of you probably know, Mitch "Mitchco" Barnett is a regular contributor to the Computer Audiophile website with his articles. He's also the author of the book Accurate Sound Reproduction Using DSP (now available in paperback). A great guy who has logged many hours back in the day in the audio production world!

The cool thing is that Mitch doesn't live far from where I am and last year, we met up at the Vancouver Audio Show 2016 (which by the way appears to be running again this year June 24-25, 2017). We chatted a bit before the show about various topics both in life and audio. From those discussions, one of the questions we wondered about was this whole notion about electrically "noisy" computers and just how "bad" the inside of a typical PC is for high-fidelity computer audio. After all, these days we see all kinds of products claiming the importance of "noise isolation" from USB cards to power supply upgrades.

At the Audio Show, Mitch kindly lent me an old computer audio card he had at home in storage which he was no longer using (in part because he's up to date with his computers and no longer runs a machine with PCI slots :-). Here it is:

Behold, the Lynx L22 24/192-capable PCI "digital audio interface" designed circa 2002. Back in the day, this package had an MSRP of US$749. It filters the power supply, is said to have very clean ground planes, and utilizes high quality components (here's a review from 2003). At a time when probably many of us were rockin' with Creative Soundblaster Live! type sound cards, this is something meant for home studios and maybe some DVD audio production... At 15 years now since the design of this device, we had to wonder - how does this sound card measure and sound sitting in a "noisy" old computer enclosure with components dating back to the era of conventional PCI (not PCIe) slots?

COMPARISON: MQA "Authentication" & Sound Quality? (Mytek Brooklyn & Meridian Explorer2)

You've probably heard or read the catch phrases from MQA over the years. "Revolutionary", "TAKE ME THERE"... "To the original performance..." Or how about using phrases like "end-to-end technology"?

As I have said over the last few months, I don't like talking about MQA based on my general impression of what they're trying to do and the way they try to convey supposed "value" to the audiophile world through their advertisements and sponsored articles in the audiophile press. Nonetheless, sometimes it's just necessary to comment and more importantly to put some of the rhetoric to the test. There appears to be a remarkable schism between those who advocate and praise MQA and those who have concerns. I'm pretty sure there are many wishing that MQA would just go away instead of complicating music playback with yet another questionable variant.

Last week, when I wrote about the idea of MQA CD, I brought up the Pono experience as another example of failure in the recent history of the industry. For Pono, the failure was perhaps rather obvious for those of us who have been listening to 24-bit and >44.1kHz music for awhile, especially those of us who have ever bothered to try an A/B-test. It does not take a genius to realise that audible differences are really quite subtle (if even there in most cases of mainstream music) and that differences do not translate to "benefit". Without clear audible benefits, there really was no way that the promise of the Pono music store could ever excite the music-buying public... Certainly not in the way Neil Young portrayed it (sure, the hardware PonoPlayer is unique but with its own quirks of course).

MEASUREMENTS: Oppo BDP-105 RCA, XLR, HDMI, and other stuff for the record (like MQA CDs?!)...

Recently, I was looking at my directory of audio measurement data and realized that I forgot to put up the measurements I had collected on the Oppo BDP-105 Blu-Ray player that I borrowed from a friend in late 2016. I believe the BDP-105 has been discontinued in anticipation of the next generation flagship. The last version of the 105 was the BDP-105D which added DarbeeVision DSP video processing. This would likely not affect the audio side which is what I explore in this article and I'll obviously leave it to the videophiles as to whether this processing is beneficial or not.

As you probably are aware, this device caused quite the stir in the audio and home theater communities back in 2013 when it was first released. For a reasonable price as a universal disk player, it was capable not only of the usual CD/DVD/(3D) Blu-Ray playback but also SACD, DVD-A, and even HDCD decoding. All with flexible digital input choices - USB, TosLink, coaxial, and HDMI. For analogue output, it has single-ended RCA (stereo and multichannel) and balanced XLR analogue (stereo only) connectors. Already in 2013, Oppo had gained a reputation as a good brand with their previous models, but I think this device really put them fully on the map for audiophiles and videophiles alike looking for a reasonably priced (~US$1200 at the time) device that neither sacrificed features nor quality.

For audiophiles, the high-resolution audio output is handled by the pair of ESS Sabre32 Reference ES9018 DAC chips inside. According to the BDP-105 Wiki for those curious: "In the BDP-105's stereo board design, the 4 pairs of DACs in the ESS9018 DAC are allocated as: 1 pair for the RCA outputs, 1 pair for the XLR outputs, and 2 pairs stacked for the headphone amplifier." The other ESS chip is used for the multichannel RCA output.

Years ago, I published some results for this player (along with a DSD followup) and showed that it is indeed a very competent high-resolution device. That was back in 2013 when I was just starting this blog. Over time, I have incorporated a few more measurement and I thought it would be fun to revisit the device. This time, with my newer ADC, have a look at the digital filter in greater detail, explore the difference between the use of RCA and balanced XLR cables, and see if digital input with the USB-B interface differs from HDMI, and the S/PDIF variants... I suspect many of us have heard the BDP-105 over the years, so this might provide a nice opportunity for objective-subjective cross-correlation.

MUSINGS: Do we "need" those >20kHz ultrasonic frequencies for high-fidelity audio?

Recently I received this excellent question and link about ultrasonic frequencies from the Computer Audiophile site:

Hi, Archimago. Visit your blog frequently and find your posts enlightening and entertaining at times without the usual smoke and mirrors.

What caught my eye in the musings on MQA utilizing the Mytek Brooklyn DAC was the selection of a musical reference which had ultrasonic, specifically musical, content. After reading the paper by James Boyk <https://www.cco.caltech.edu/~boyk/spectra/spectra.htm>, ; I have been interested in the subject of ultrasonics and their (potential) effect on the listening experience fully recognizing that these frequencies are well above the capability of human hearing. Included would be identification of recordings that have musical ultrasonic content.

Given that formats such as PCM (24/96 or higher) and DSD (2x or higher) [Ed: remember that even DSD64 1x can go >20kHz] have the potential to capture musical content above 20kHz, I am intrigued by the possibilities. As with all HiRes formats, I understand that not only all components of the recording chain but also the reproduction chain must have frequency response greater than 20kHz to accomplish this. I do see where speakers are being offered which are spec'd to 40kHz and as high as 100kHz. There are also numerous add-on "supertweeters" being offered which have this capability as well.

IF the topic were of interest to you and worthy of your time and consideration, I for one would be most interested in your musings on the subject.

My apologies for using this Musing as a portal for my inquiry but did not know how else to contact you with the proposal.
FWIW, given the potential of the existing HiRes formats to capture the musical experience if fully realized, I too am less than interested in MQA as the latest flavor-of-the-day.

Frank Zawacki
Connecticut Audio Society

Thank you Frank for the link, interesting discussion and question. I try to do what I can to collect information and synthesize posts to provide hopefully reasonable thoughts on these matters; mixed with some measurements and personal subjective impressions as appropriate.

HOWTO: Building and Installing the Raspberry Pi 3 "Touch" Audio Streamer.

Raspberry Pi 3 + 7" Touchscreen (left) and Squeezebox Touch (right): for the Pi device, I still had the plastic screen protector on in the picture, hence the bottom left tab...

I showed you guys this picture last time of the Raspberry Pi 3-based Streamer device with official 7" touchscreen and HiFiBerry DAC+ Pro. As you can see from the image, it's very much capable of being a "clone" of the Squeezebox Touch. Furthermore, it's highly affordable with even more hi-res audio potential such as the capability to stream bitrates beyond 96kHz (remember, the stock Touch goes up to 96kHz, enhanced to 192kHz with Triode's EDO plugin).

In this post, let's have a closer look at the device and some instructions / suggestions to build one.

MUSINGS: Computer Audio Part II: The Basics & Suggestions

For many readers, I'm sure what I'm about to write here is relatively "old hat" by now... However, in the spirit of "Computer Audio Demystified" last week, let's talk about this powerful way of storing, categorizing, and playing our music by exploring some aspects of the foundation of computer audio in a way I hope newcomers will find reasonably accessible. I do make some assumptions in the writing that the reader has some basic knowledge of computer usage and networking. Let's consider the "architecture" of what someone might want to build, and a few reasonable options if we were to start from scratch with full disclosure of the price to build such systems.

I can imagine that some folks might need to overcome their phobia around computers. If you're motivated, just put in some time, a little patience and don't be afraid to "play" with it. More likely than not, once one has tasted the convenience and have found one's "groove", going back to only spinning physical media will likely feel archaic after a short while :-).

First, permit me to remind everyone about the two most important determinants of sound quality in a high fidelity audio system:

1. Put thought and money into good speakers, good pre-amp/amp(s), good DAC and a good sounding room.

2. Make sure the system is acoustically quiet; ideally silent.

Point 1 is obvious. The primary factors in sound quality (ie. "fidelity" achievable) are the room, speakers, and amps in that order - these are the prime candidates for sound distortion, not your computer or DAC (and certainly not stuff like cables). And Point 2 is an obvious corollary for any equipment we put in the room since we don't want the system itself to act detrimentally - this includes noisy computers, buzzy amp transformers, ground loops through the pre-amp, etc. Remember that the purpose of computer audio is simply about storing the audio library data reliably, making available a conveniently handy user interface, and the bits are being delivered in an accurate fashion to the DAC; whether internal to the computer audio device or say an external USB DAC. There is no mystery in how to come up with a solution to achieve these goals.

MUSINGS: Computer Audio Part I: Demystifying "Computer Audio Demystified"

It's nice to see that some of the seminars at the Rocky Mountain Audio Fest (RMAF) 2016 have been posted on YouTube. It gives all of us who may have wanted to visit a chance to review the "latest and greatest" tips and updates...

Although the RMAF is hosted by the Colorado Audio Society, remember that much of the material comes from Industry; with of course the potential for vested interests influencing the content. I think many visitors to this blog would be interested in computer audio, so let's spend some time looking at the information disseminated... For your consideration, let us explore the one presented by Steve Silberman of AudioQuest - "Computer Audio Demystified" (RMAF 2016):



Feel free to watch the full 1.5 hours. For today's segment, we'll look at a bit of reality testing vs. myth vs. mysticism. You'll notice that the comments section for this video on YouTube has been turned off. Interesting. How else to discuss the contents then than in a blog post like this, right? :-)

MEASUREMENTS: A look & listen to Roon Bridge - Raspberry Pi 3 Streaming (HiFiBerry DAC+ Pro & USB DAC)

Last time, I talked about Roon and discussed my experience with it using the NUC as the primary installation and playback. No doubt, you are aware that many people will use inexpensive devices like the Raspberry Pi 3 to handle playback distributed around one's home... And no doubt you've also come across much hyping about more expensive, low power devices when for around $100 and a little know-how, you can get it done quickly, easily and sounding great.

First, I just wanted to practically lay out a simple way to install Roon Bridge on the Pi 3 that worked for me and using which I will run a few tests to demonstrate the sonic output. Remember that the network protocol from the Roon "Core" (my Windows computer) to the Roon "Bridge" (Pi 3) is what's called RAAT (Roon Advanced Audio Transport). It's a protocol with a number of benefits as highlighted in the link.