HOWTO / MUSINGS: Playing with Digital Filtering - Impulse Responses and Frequency Effects resembling Chord, Old-Skool Meridian, MQA, NOS...

Remember folks... With anti-imaging filtering applied to digital playback, there are no gross "stairsteps" in the oversampled/upsampled analogue output. Regardless of what you might see from misleading audio ads trying to pigeon-hole "digital". The exception being non-oversampling DACs that specifically choose to go down the stair-step path.

As you may know, I've been using a Raspberry Pi streamer with LMS over the last year for most of my listening. As described in that Pi "HOWTO" article, I've been using the piCorePlayer software to stream.

One of the nice features of piCorePlayer is that it allows easy control of upsampling by using SoX; in the "Advanced" settings is the ability to pass along instructions to control the digital filtering used. Combined with a good DAC that accepts high sample rate PCM, we can try listening for ourselves and gain an appreciation of the differences that digital filtering make. The cool part of this is that it allows us to "emulate" the kinds of filters used in the audiophile world.

In this post, let's play with some of the parameters and show the kinds of impulse responses and "digital filter composite" graphs we can achieve...

MEASUREMENTS: Oppo Sonica DAC and Bluetooth 4.1 (Low-Complexity SubBand Coding) Audio...

Merry Christmas everyone! Hope things are going well out there.

As you know, earlier this year, I had a look at the Oppo Sonica DAC including measurements with the "fixed" firmware. Over the last few months, I've actually sold the device to a "more needy" audiophile buddy. Remember, the DAC measured and sounded fantastic, but truth be told, it is to the point where I personally am not able to differentiate the sound quality from my already excellent TEAC UD-501 bought in 2013 and I didn't absolutely "need" any of the new features it provided. Furthermore, as you know from my discussions of digital room correction, sound quality IMO is more a function of other factors than just the DAC accuracy.

Before I parted with the Sonica DAC, I did make a few other measurements out of curiosity. One of the measurements was to have a listen and look at the Bluetooth 4.1 audio playback from my Samsung Note 5 phone to the Sonica.

MUSINGS: Thoughts on fake 4K, post-truth and film "format folly" (70mm film & Christopher Nolan).

Since returning from my Asia trip. I see that new toys for Christmas have now been released including the new Xbox One X (which I mentioned a few months back).

Although it seems like there may be issues that need to be fixed, one nice feature of the Xbox One S and X machines is the ability to play the new Blu-Ray UHD disks which have been available since March 2016. Though there are a number of disks out there now, I suspect the growth has not been spectacular... Not unexpected really since the jump from 2K (1080P) to 4K (2160P) resolution does require the right conditions as laid out previously to be truly appreciated, plus, like music, movies have gone "virtual" with streaming being the primary mechanism of consumption.

For this post, I thought I'd put together a few discussion items about video IMO worth thinking about as we are very much in the era of the 4K videophile!

HOWTO: Integrating WavPack 5-compressed DSD into Logitech Media Server (LMS).

piCorePlayer streaming WavPack-compressed DSD128 (1-bit, 5.6MHz) to TEAC UD-501 from recent nightly version of Logitech Media Server 7.9.1.

As I mentioned last time, it's great to see that DSD compression and metadata tagging are available in the form of WavPack 5. Starting from the post by michaelvv on the Squeezebox Forum, I decided to spend more time on getting WavPack-DSD working in LMS and managed to get it working quite stably installed on a Ubuntu Linux (currently 16.04 LTS) virtual machine in the Windows Server 2016 computer that serves as my repository of data, movies, and music. For a description of the initial software install, have a look at my HOWTO: LMS + BrutefirDRC Plugin post from last year. The hardware these days is my Intel i5-6500 server machine described here.

MUSINGS: On DSD, tagging, compression and conversion... Time for WavPack 5.

Many moons ago (back in 2013), I discussed DSD audio. While over the years I've talked about DSD from a a number of different angles (eg. JRiver realtime conversion listening, PCM <--> DSD conversion, conversion 2015, equipment DSD playback measurements like PonoPlayer / TEAC UD-501 / Oppo BDP-105 / Oppo Sonica DAC), concerns from that very first discussion about DSD still irks me these days!

The main issue is simply this: the lack of ability for gear and software to support both tagging and data compression when dealing with DSD. This IMO truly has been a ridiculous state of affairs for so many years! Despite years of cheerleading in the industry and even smaller sales outfits like NativeDSD Music already putting files out there for consumers, the relative inelegance of it all is rather silly.

As usual, I find it rather baffling that the typical mainstream audiophile press remains silent on deficiencies like this. To me, it is issues like these, while perhaps not "sexy" nor provides the press something to market to consumers, that when addressed can actually move the hobby forward. Unlike yet another megabuck product that provides a few minutes of eye-candy at best and affects the few, "infrastructural" changes can affect the many. Yet another example of the myopia of the audiophile press and an inability to muster any leadership in changing the industry and hobby in meaningful ways.

HOWTO: AMD Ryzen 7 1700 overclocking to 1800X speed while maintaining power savings...

Greetings from Asia.

Okay with all the recent chatter on MQA, let's take a little break from audio for a bit and talk about something much less controversial :-). In fact, this is downright basic for all the computer overclockers out there...

Remember a few months ago, I upgraded to the AMD Ryzen 7 1700 CPU. As discussed in my previous article, I upgraded to a computer with this processor for workstation purposes, not gaming or anything like that. I've certainly been impressed by the speed already but as one who enjoys tinkering with the machines, I thought it would be fun to try overclocking without sacrificing power efficiency...

MQA: FINAL "Final" comments... Simply put, why I don't like MQA.

Looks like an interesting art exhibit :-).

I know... I said the previous post was "final". But I just had to kick the horse one more time. :-) Seriously, if you're sick of MQA chatter already, don't bother reading this - you've been warned!

This past week, I added my views to this thread on Computer Audiophile (from about page 198 in an epic thread with >5000 comments!). I know that forums can get pretty heated and ugly, but it is good fun sometimes so long as you don't let it get personal - it never has to, we're talking audiophile stuff after all - first-world problems, nothing life or death. Since forum threads and comments tend to get lost easily, I thought it would be reasonable to just enumerate some main talking points in the hopes of furthering clear debate (if still necessary)...

MQA: "Final" thoughts... On Politics & Paradigms.

Cartoon looks about right and reflective of MQA... From article here.

In the last few weeks as I was preparing the series of posts discussing the MQA blind test, I noticed The Absolute Sound (TAS) ramping up the hype again in September with two articles in defense of the value of MQA. Let's use those articles to close off discussions about MQA among other ideas at least for a bit here at The Musings...

Sure, I'll be around to add my two bits and answer questions where I can, but to be honest, I'm a little tired of MQA by this stage and how much of a big deal it isn't, IMO.

MQA Core vs. Hi-Res Blind Test Part IV: Subjective Results & The Wrap Up...

After having gone through the "core" results and subgroup analysis from the MQA Core vs. Hi-Res PCM Blind Test, let's review and post some subjective comments gathered in the survey. This provides an opportunity for us to see how people described what they heard and since we know what the preferences were, put them in the context of whether the descriptions referred to a bias towards the MQA decode or standard PCM...

MQA Core vs. Hi-Res Blind Test Part III: Subgroup Analysis

This is Part III of the summary and results of the MQA Core decode vs. standard PCM Hi-Res blind test following from the "core" results last week.

At this point, we know that if we look at the "big picture", evidence suggests that there are minimal audible differences. So if we dig into the data set a bit further, let's see if we can ask questions based on the subgroups identified. I'm sure many of you have been curious about some of these questions for awhile but until having access to a large enough database such as this, it's difficult to obtain answers.

Let's then ask a few questions and interrogate the database for hints...

MQA Core vs. Hi-Res Blind Test Part II: Core Results

As you know, Part I - Procedure is now published. Within it, I laid out in detail the test, how it was constructed, and how data was collected. Today, we'll embark on the exploration of the data itself. While I will try to conclude with some general points by the end of this post, I will not have had time to analyze everything quite yet. I'm currently anticipating at least another couple of posts to fully flesh out the data set including posting some of the subjective comments made by listeners. I feel this is the only way to properly thank those who took their time and provide as much information as possible to answer any lingering questions.

Let's start... Today, let's focus on the "core" or "headline" results I think most of us are interested in. Who are the people who tested and submitted results? What overall were their preferences? What was the result for each specific track? How confident were the respondents about their choice? And how significant were these findings ultimately?

MQA Core vs. Hi-Res Blind Test Part I: Procedure

Introduction:

As you are probably aware, through the last 2 months on this blog, I've been collecting data to determine the audibility of decoded MQA versus the same piece of music originating from the "master" high resolution source. Please refer to the Test Invite article from mid July 2017.

Over the last couple of years, I have been curious about the MQA technique and followed the evolution of the "technology" as it has been touted as being the next step in digital music playback. Throughout the last 2 years, I have tried to develop an understanding of what it's doing beyond simply the superficial talk around being "revolutionary", "fundamentally changing the way we all enjoy music", nebulous claimed links to "neuroscience", or talk of bringing the "studio sound" to the consumer. If you look back, I have written articles looking at:

- Initial musings... 

- The undecoded MQA file. 

- Decoded vs. undecoded Explorer2 output. 

- Dicussions of MQA's partially lossy nature. 

- Comparison of TIDAL / MQA Decoding with "studio master" tracks. 

- Mytek Brooklyn hardware MQA decoding. 

- Discussion of digital filters and relevance to MQA. 

- Comparison between Meridian Explorer2 vs. Mytek Brooklyn ("Authentication?"). 

- Dragonfly Black MQA "Rendering" and filter. 

- Mytek Brooklyn MQA filters. 

- The "full monty" of MQA filters from the Dragonfly Black MQA-enabled DAC.

MUSINGS: Evidence of digital player jitter with asynchronous USB DACs? Melco N1ZS20/2 review in HFN&RR...

The UK magazine Hi-Fi News & Record Review is interesting. Like Stereophile here in N. America, it includes objective measurements. Over the years, I've seen times when they have criticized questionable "hi-res" downloads showing nothing more than upsampled music. But they also seem to like "showing" rather meaningless measurements such as a few years ago with their USB cable roundup.

Recently, I believe in the May 2017 issue, they reviewed the very expensive "cost-no-object" digital server - the Melco N1ZS20/2. This device is the "mk2" of their top-of-the-line music server/player with the capability for data output through ethernet or USB connection to one's DAC.

MUSINGS: How much amplifier power do you really "need"? Why not test for yourself?

Much has been discussed about amplifier power over the years; here for a short primer, here for a contemporary take with advice from Crown, and here for an oldskool audiophile take on the matter when dinosaurs and tube amps ruled the land (notice the positive sentiment towards even low power transistor amps compared to the low-wattage tube jobs in this article!).

We often hear the question: "How much power do I need?" A very reasonable query of course when we're thinking of buying a new amplifier.

The answer to that question of course really depends on your needs. The bottom line is that it really is about your context and preferences, the quantity and quality of the amplifier you need can vary based on all kinds of factors. When it comes to quantity, it will of course depend on the efficiency of the speakers you listen to along with size of your room, distance to the listening position, placement of the speakers, and absorptive/reflective surfaces in the space.

MUSINGS: Increasing the Dynamic Range of compressed audio with DSP... (And is this why vinyl DR is higher!?)

Sadly, the good doctor's diagnosis applies to too many of the recordings we listen to these days.

I mentioned last week a recommendation for July Talk's Touch album at the end of that post. There are a number of catchy and enjoyable tracks on there... However, if we put this album through the foobar DR Meter, unfortunately, we see an album with really nasty dynamic range compression - DR4. Yuck.

Hmmm... Is there any way to change that?

MUSINGS: The 3 Main Home Computers 2017 (Workstation, Server, Gaming) & Thoughts on Gaming Consoles (like the upcoming Xbox One X)...

In the heat of summer, it is nice to get some time off to fix up around the house and do something that I typically take no pleasure in - rebuilding computers and reinstalling the OS & software! It requires a level of "Zen and the Art of Computer Maintenance" that I can only muster up every few years :-).

If you're like me, at home, you might have a little cadre of computers for work and personal purposes. As painful as it is, every few years, I'll update the OS, maybe tweak the hardware here and there (everything from cleaning up cables, vacuuming out dust, updating motherboard firmware and drivers, and the occasional refreshing of the heatsink compound). Updating a less "mission critical" machine like a HTPC or game machine (such as previously discussed) is not a big deal because in my view, that won't affect the others. However when I update the powerful main Workstation, I try to reuse the parts for some of my "lesser" machines; can't let perfectly good high speed CPU, RAM, and motherboard go to waste.

MEASUREMENTS: SMSL A6 as DAC (Part II)

SMSL A6 Integrated Amp - playing through USB 24/352.8kHz signal. Notice the matte/satin finish of the aluminum case. Probably need to wipe it down once awhile if dusty.

As I mentioned last week with the initial review of the SMSL A6 integrated amp, this is a versatile device. It features an AK4452 DAC first released in 2015 which though not "top of the line", does perform very well with a potential 115dB SNR and is part of the "Velvet Sound Architecture" range of "Premium" DACs. For those keeping track, currently, the flagship DAC from AKM is the AK4497, capable of 5-channels and rated at 128dB SNR; they call this series the "Verita" which competes with the best of the ESS DACs like the ES9038Pro previously discussed in the Oppo Sonica DAC measurements and review. By the way, another claim to fame of the AK4497 is that it has a "volume bypass" mode which allows the DSD data to bypass the internal delta-sigma modulator; a more direct processing path... As usual with new features in otherwise mature technologies, whether this is audibly better is probably up for debate.

Today, what I wanted to test out with the SMSL A6 are the RCA and headphone outputs from this device. As usual, along the way we'll have a peek at jitter results, the antialiasing filter being used, and check out the various inputs - USB compared to the S/PDIF variants of TosLink and coaxial.

REVIEW: SMSL A6 integrated amplifier - Part I: Overview and Subjective Listening (and briefly about USB cables)

SMSL A6 at home in my living room system with Tannoy Mercury Mx2 speakers. Doug MacLeod's Break The Chain (2017, Reference Recordings 24/176.4 downsampled to 88.2kHz, DR16) playing over Logitech Media Server.

For many years, my father's audio system consisted of various CD players, a Sony turntable and vintage pre-amplifiers. This then fed a tube pre-amp which then sent the signal to either a tube-based Onyx SP3 Melody amplifier or vintage solid state Pioneer amplifier to feed his Klipsch Forte speakers which have been cleaned and refurbished with new crossover parts over the years.

In the last 5 years, I've supplemented his system with various DACs for the CD player, and most recently got him a streaming connection with my Logitech Media Server based out of my home server using a Logitech/Squeezebox Touch.

This set-up sounds very good. The classic Klipsch speakers really do throw up a fantastic soundstage, have quite a smooth sonic signature (though a little mellow for my taste), is extremely sensitive, thus easily powered by low-wattage amps.

He has gradually transitioned to almost exclusively digital streaming, finding the convenience indispensable compared to spinning disks (whether of the polycarbonate or vinyl variety). As much as the tube and large integrated amps sound great, over time some of those components have needed maintenance and I figured it would be nice for him to try out something much simpler than manually turning on/off multiple devices every time he wants to hear good sounding audio. Thus, the purchase of the SMSL A6 integrated DAC/amp.

MEASUREMENTS: The AudioQuest Dragonfly Black MQA filter set...

Good movie from the 90's!

Just a quick note while we're doing the MQA blind test!

A few weeks ago I posted on the Dragonfly Black and the MQA filter impulse responses. I noted that based on Måns Rullgård's work, although there are potentially 32 filters available when "Rendering" with upsampling to 192+kHz, I only showed 0-8 in that previous post.

Well, using the same kind of impulse response diagram previously (captured using my Focusrite Forte 24/192 ADC), here's the AudioQuest Dragonfly Black "full monty" of impulses...

INTERNET BLIND TEST: MQA Core Decoding vs. Standard Hi-Res Audio

Introduction:

Well my friends, the time has come... Yes, it's another Internet Blind Test!

As a "more objective" hobbyist blog, within these pages I try to demonstrate facts, figures, and opinions as best I can with the hopes that it educates the typical "audiophile" out there who loves music and wants to at the same time understand the hardware and technologies used in the world of high-fidelity. I do this for fun with the hopes that in time, as a group we can be "more rational", each of us better able to adjudicate what makes sense, what works, and what ultimately has either very little worth or should even be considered worthless "voodoo".

Over the last few years, as you've no doubt noticed, a number of my posts have been looking at MQA and the claims made. I'm not going to rehash much of that here (feel free to start on this page and check out the links at the bottom accumulated over time). As we've come closer to understanding details like the filters used and how the "Rendering" works, there is one very important piece that remains rather nebulous.

This last piece has to do with claims of time domain "de-blurring". The idea that some kind of DSP has been used to affect the sound quality, ultimately "improving the analogue-to-analogue performance" from the studio to one's own DAC output (ostensibly using various techniques including measuring and aligning impulse responses of the devices used in production and playback). How this works is of course proprietary and hidden in the encoding system which we as end-users have no access to.

MEASUREMENTS: MQA Filters on Mytek Brooklyn & Thoughts on USB Doohickeys

Hey folks... It's summer and I'm in and out of town doing a bit of R&R mixed with the day job.

I sent my friend with the Mytek Brooklyn and Fireface ADC a package of the MQA "Render" tagged files for testing. As you can see above, that's what the MQA filters look like with the Mytek Brooklyn serving as "Renderer" for the impulse responses. If you look at the top row, we see that the Brooklyn's standard digital filter at 24/96 is the same as what MQA uses for playing back 96kHz "original" unfolded PCM. This is different from the Dragonfly Black DAC presented a couple weeks back where the standard filter at 24/96 is a much sharper one and would shift to the weaker MQA filter only when it detects the MQA Render tagged data.

MEASUREMENTS: AudioQuest Dragonfly Black 1.5 - PART 2 (On "MQA Rendering")

AudioQuest Dragonfly Black - "rendering" MQA playback. Dragonfly logo turns purplish...

For those keeping track, the story of MQA has slowly evolved over the last few years. Initially, it was supposed to be just a technology incorporated into DACs that would take an encoded file (typically 24/44 or 24/48) and almost "magically" transform this data into the "original" high resolution (equivalent to 24/192+) sound while maintaining standard PCM playback compatibility. This was the case with the first products like the Meridian Explorer 2. Over the years, it appears that concessions have been made. Software decoding rather suddenly was introduced in early 2017 with TIDAL's support for MQA; branded as "MQA Core". At around the same time, DACs were classified as either "MQA Decoders" for components that can handle these 24/44 or 24/48 files start to finish (Meridian, Mytek DACs), and "MQA Renderers" which require the computer software perform initial "unfolding" to high-res samplerates (88 or 96kHz) followed by some kind of final processing to the sound performed by the DAC presumably to allow the sound to be more "accurate" to the studio production, or "authentic" (whatever that means).

With the recent firmware upgrade to version 1.06, the Dragonfly Black DAC now belongs to this latter category of "Renderer". As far as I am aware, it is the first of these kinds of devices to be released without "Decoding" capability.

MEASUREMENTS: Audioquest Dragonfly Black 1.5 - PART 1 (General)

Four USB mini-DAC's (back to front): Light Harmonic Geek Out V2, Audioquest Dragonfly Black, SMSL iDEA, AudioEngine D3.

As I showed a couple weeks ago, I have in my possession one of the Audioquest Dragonfly Black DACs for testing. I'm actually borrowing it from a friend so it's not going to be in my possession for long... Long enough for me to listen and run some objective testing to see what the "deal" is.

I think it's useful to show these test results on the Dragonfly because AudioQuest clearly has a healthy advertising budget and promotes it quite heavily on audiophile sites with ads in magazines as well; as such it's a bit of a "standard" even though a number of other alternatives exist. For example, a few weeks back, I showed the measurements for the SMSL iDEA which I thought performed objectively amazingly well for such a small device although I had some issues with seamless connectivity to Linux / Android. As you can see in the image above, I have tested a few others of these kinds of  DACs already including the AudioEngine D3 measured in 2014, Light Harmonic Geek Out V2 in 2015, and also the previous revision Dragonfly v1.2 in 2014 which I don't have on hand any more (it was given as a gift to a friend).

MEASUREMENTS: Oppo Sonica DAC (ESS Sabre ES9038Pro based device)

My Raspberry Pi 3 "Touch" on top of the Oppo Sonica DAC - notice the DAC can handle up to PCM 768kHz (and DSD512 / 22.4MHz).

A few weeks ago, I published the preview of the new Oppo Sonica DAC and noted some issues I ran into with unusual jitter and digital filter measurements. Thankfully, Oppo was able to correct the issues within a week with the beta firmware and I see that the official firmware incorporating the improvements is now out - Sonica-33-0511 on the support website (May 15, 2017 date).

With it becoming official, I figure it was time for me to run and post results of objective tests on the device. This should give us a taste of both the capabilities of this Oppo Sonica DAC as well as look at what the "latest and greatest" ESS Technology ES9038Pro 8-channel DAC chipset is capable of... Although I have not seen it specified anywhere, my assumption is that the stereo configuration in this device ties 4 of the DAC channels for each of the stereo pair.

MUSINGS / MEASUREMENTS: Thoughts on Vinyl LP Fidelity... (And thoughts on Sgt. Pepper's 50th Anniversary Remix.)

Alright... Let's not get worked up about the cartoon :-).

I know, the debate between vinyl and CD (digital) remains one of the greatest "wars" of the audio world; not that it should be a big deal IMO... As usual in most audiophile conflicts, there are many words spilled about the topic, but it is rare to see "data" or actual direct comparisons. For example, look at Wikipedia's entry for "Comparison of analog and digital recording" and we see no actual illustration to demonstrate differences.

Years ago, I wrote a little about this here (and I think it's only fair that I have a digital-preferring Batman cartoon). As you know, over the years there are all kinds of vinyl evangelists going around touting the superiority of LPs over CDs and digital overall (and vice versa although I'm not sure the digital camp is as evangelistic). Here's a nice example of all the awesomeness that is vinyl based on someone's opinion.

As I've said before, I agree that there are some great qualities about having an LP collection. So long as you have the space for the non-biodegradable collection, the beauty of the artwork is wonderful. It's comforting and collectable memorabilia. And likewise the sound can be alluring in the same romantic way. For some, the ritualization of the playback process can bring with it that sense of security and physical engagement as well.

MEASUREMENTS: SMSL iDEA USB DAC / Headphone Amp (ESS Sabre ES9018Q2C + XMOS XU208)

In 2015, ESS revealed its latest generation of DACs at the CES show. One of the interesting new products revealed was the SABRE9018Q2C, a tiny 5mm x 5mm SoC claiming very high audio quality out of an integrated DAC/headphone amp operating with low power along with the ability to decode a wide range of sample rates.

I was contacted by ZugZugOrc on Computer Audiophile to have a look at a recently released USB DAC he wanted to buy for some measurements based on the above chipset. So we made an arrangement where he sent the package to me to have a look at and subsequently after I'm done, I would send it off to him to use :-). Thanks Zug for the opportunity!

Here's the device - the SMSL iDEA (can be found on Amazon for ~US$86 currently), a mini USB powered "stick" based on the ES9018Q2C "audiophile-quality" mobile DAC capable of accepting up to 32/768 and DSD512!

SMSL stands for  "ShuangMuSanLin" Electronics Company based in Shenzhen, China. I was sent the black one, but the device is also available in red.

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.

MEASUREMENTS: Roon 1.2 (with Intel NUC 6i5SYH)

NOTE: I know that just a couple weeks ago, version 1.3 of Roon has been released and I'll perhaps look into that a bit later once some of the initial bugs are stamped out and the system matures a little. Clearly 1.3 has a few new interesting features but the basic bit-perfect playback function I trust would be the same which is what I'm aiming at exploring in this article.

Over the last few years, I have already gradually made my way across the different audio ecosystems that most audiophiles find themselves interested in. Starting with the venerable Squeezebox / Logitech Music Server system (eg. Touch, Transporter), to standard Windows PC and Mac OS X playback, to questionable software (like JPLAY and the JPLAY update), to even just as questionable OS tweaks (eg. Fidelizer), to more recently looking at DLNA streaming using low power devices like the Raspberry Pi 3 and ODROID-C2.

For today and the next few weeks (let's see how this goes), let's spend some time on Roon, another computer audio system much lauded in the audiophile press and see if we can make a few measurements and comment on some observations and thoughts...

MUSINGS: Discussion on the MQA filter (and filters in general)... [Update: Including a look at the classic "Apodizing" filter.]

Here's an interesting comment from the post last week...

CBee 7 February 2017 at 04:47

Excellent article but I have one query. On Sound on Sound they say "MQA claim that the total impulse-response duration is reduced to about 50µs (from around 500µs for a standard 24/192 system), and that the leading-edge uncertainty of transients comes down to just 4µs (from roughly 250µs in a 24/192 system)." In that case wouldn't you need an ADC with higher resolution than the RME Fireface 802 in order to see any real differences between the Reference and Hardware MQA decode?

As I said... Dammit CBee! Now you've made me post another blog entry on MQA :-).