"High End" Audiophile Science? On Milind N. Kunchur's hard-to-believe research articles.

It has been a busy week so let's keep this article somewhat shorter. ;-)

Beyond the typical audiophile magazines, websites, and videos, I think it's interesting once awhile to think about some of the research out there in the academic literature related to "audiophile" topics.

As I have said many times, I believe that typical 2-channel hi-fi audio is very much a "mature" science these days so on balance it's probably unlikely that understanding of core technologies should be too contentious. I know, some audiophiles and companies will protest this idea with the belief that human hearing somehow has much more potential and that we cannot measure all domains of auditory acuity as applied to our audio tech. As science-driven hobbyists, since we can perform blind tests and show that people have difficulty differentiating high bitrate MP3 from lossless, even relatively high distortions are difficult to hear, and hi-res audio is generally indistinguishable from 16/44.1 lossless (except for a few minor instances which can be statistically significant but practically not likely relevant for music listening), I think the onus of proof remains on those who make contentious or dramatic claims outside of the standard paradigm.

EARLY LOOK: The E1DA Cosmos Scaler prototype. As usual, Neil Young (in "World Record" album interview) remains neurotic against digital...

 

Today, let's talk about something rather unique.

In the image above, we see the E1DA Cosmos Scaler in use as I was running measurements of some DACs I have around here. As I mentioned last time, this is a prototype product which although has been announced/discussed online, as far as I am aware, is not at the stage of imminent production or public release. As such, be mindful that details I describe here might change if this were to be released as a product.

The Scaler functions as a balanced 2-channel in/out pre-amp that can apply 16 discrete levels (this is not a regular volume knob for routine volume control) of very clean amplification (using OPA1612) from 0dB to +26.7dB along with an "auto-ranger" feature that aims at a target voltage level to feed the ADC. Along with this, the Scaler's stable high 200kΩ balanced (100kΩ unbalanced) input impedance resolves one of the limitations of the Cosmos ADC; the lower input impedance for example 1.66kΩ at a commonly-used 4.5Vrms setting.

Thanks again to Ivan Khlyupin (IVX) for sending me the package to test out.

As with any pre-amp product, the question is how quietly does this device perform when feeding the output into a high-resolution measurement ADC in this case. And related to that, whether the device adds any of its own distortions.

Accurate Sound's Hang Loose Convolver Multichannel on low power Mini PC. The disgraceful AQVOX ethernet switch. And some E1DA upcoming evaluations.

Over the last few weeks, I've been using the inexpensive Beelink Mini S Intel Celeron N5095A PC in my music system. Recently, I posted on using it in Linux as a streamer with HQPlayer upsampling and for multichannel Roon capabilities. As you can see in that post, for audio purposes, even this level of CPU performance on a modern entry-level machine is enough for what would be advanced PCM upsampling (ie. 1M-taps realtime PCM) and even IMO very good PCM-to-DSD256 performance. More evidence to remind us that there's generally no need to get excited about some of the more expensive "audiophile" computers and streaming machines which are often embedded low-power computers at heart.

Recently, my friend Mitch Barnett of AccurateSound.ca wondered if I could look into the performance of his latest version of Hang Loose Convolver (HLC) with this low-power computer using my power limited and quiet fan BIOS settings. HLC is an advanced standalone, VST3 plug-in, or AU (Mac) plug-in that provides the ability for audio lovers to load in various convolution filters, allows for easy level matching, and provides basically immediate switching (0.1ms) between these filters for accurate A/B listening comparisons. Let's take a look at this on the Beelink.

The studio production: The Audiophile Society & Chesky's Mega Dimensional Sound; Revolver Remix. Is there an "absolute sound"?

Above, you see some recently added albums on my Roon server. I thought it might be fun to focus this week on the music instead of hardware and discuss a little more on this so-called "absolute sound" (the concept, not the name of the Harry Pearson-founded magazine) some audiophiles are supposedly going for (touched on this somewhat years ago). 

I don't know if Pearson described his concept of the "absolute sound" with much greater depth beyond the oft-quoted, vague quality of "the sound of actual acoustic instruments playing in a real space" which may or may not be hard to achieve these days depending on one's threshold of what sounds "real". Let me know if you've come across any other articles on this that defines the concept with greater detail. To be honest, I don't think I've met any audiophiles who still believe that there is a single "absolute" subjective sound we should all be striving for, but it's good to be clear about it and maybe lay it to rest.

When it comes to music, I have rather eclectic tastes. As I mentioned last time, I've been checking out some electronica, hence the amane ＋ 曇った空 (Kumottasora) album 彷徨 (Wandering) (DR7, 2017) off BandCamp on the list. You can have a listen to track 2 "~ Discontinuity ~" on YouTube. It's an atmospheric piece of work that's very much at home in the Blade Runner universe I can play in the background without getting distracted; in fact, excellent background music when doing medical charting on the computer - the bane of the medical professional's existence these days. ;-)

To the right, we see a couple versions of David Chesky's The Great European Songbook (DR13, 2022). As you can see, I've labelled the cover image for easy identification; we have both a "Headphone Mix" and "Speaker Mix".

Blog Post #502: Musings on a decade of audiophilia, maturation, objectivism and the road ahead.

Well guys and gals, this marks post 502 since the start of the blog back in 2012, although articles really only started flowing by 2013. As we are approaching the latter months of 2022, it's amazing to think that a decade has flown by!

Over the years we have touched upon a huge number of audiophile topics. Much of the ideas and experiments over the years have and will continue to serve as the foundation for me in the days ahead as a music lover and "hi-fi" audiophile. Before embarking on this blog, I remember the frustration of feeling entrenched in audiophile obsessions over the fears and uncertainties around things like whether I needed expensive cabling, whether the ethernet switch was deteriorating my audio stream, concerns about the "noise" from my computer, and if for some reason jitter was further destroying my sound. I remember recognizing that none of those anxieties were ever fully addressed or clarified by product manufacturers or the mainstream magazines of the day, and there were little resources out there on YouTube or other websites. Descriptions were vague, and as I recall, nobody ever could clearly express to me what jitter sounded like for example, despite prominent claims. Other than suggesting that handing over money was the solution by buying and "listening for yourself", hobbyists could seem to do nothing else - powerless in the face of dramatic claims.

I remember thinking at one point: "How problematic are these issues, really?!". Given the decades of audio hardware evolution, and in the context of all that we know in the 21st Century about the engineering that has gone into these human-designed and assembled electronic devices, is it reasonable that hobbyist audiophiles seemed to blindly stagger in the dark, typically discussing these things with little facts, or figures, easily drawn into opinions and assumptions that can swing to extremes or seem so idiosyncratic depending on the subjective whims of the reviewer who supposedly "hears" things?

Even where there are measurements (like in the pages of Stereophile), it also seemed odd to me that the objective results appear to be subservient to unsubstantiated subjective comments. If the subjective reviewer heard some "harshness" and the DAC showed higher jitter anomalies, it's not hard to use that as the "attribution theory". But if the DAC is expensive from a prominent name, more likely than not the subjective listener likes it, and the impact of sometimes exceedingly poor measurements appear softened and the device still gets an overall recommendation (look at the measurements for this).

For this post, I hope the reader will indulge me with an opportunity to meander into thoughts that have been bouncing in and out of my mind over the years, and consider expectations over the next decade.

Using low-power Beelink Mini S as Linux Roon streamer - HQPlayer (PCM 8x, DSD256), and HDMI multichannel. (A superior DIY M-Scaler?)

No worries! Putting a little low-power computer like this on top of the DAC did not affect noise level from the Sabaj DAC RCA/XLR outputs. Don't do this with more powerful computers obviously...

As expressed previously, my philosophy around computer audio is that given the speed of progress in computing technology, it really makes no sense to be building expensive and very fast computers as audio playback/processing devices. For me, if I have a general computer in an audio room, I would want to keep electrical noise low (ie. low power) while also targeting an ideally fanless solution. Inevitably, in less than 10 years, a powerful computer today would be very much obsolete. Monster machines would more than likely end up at the bottom of your closet with little value or interest left even if one wanted to sell. In fact, unless I'm doing a lot of 3D graphics, gaming, or editing videos, IMO progressively smaller, quieter, lower-power (let's aim for 10W or less with excellent performance!), and less expensive machines are where progress is heading for consumer-level general computing.

This is in part why on this blog, I've expressed much more interested in streamer systems like the Raspberry Pi devices or recently silent or very quiet MiniPCs (like the power-limited Beelink Mini S last week). As time goes on, one can judge objectively if technological progress and software updates like new DSP algorithms represent improvements in sound quality. If there are truly gains to be had, the machine can then be repurposed/replaced without feeling that one has wasted hundreds if not thousands of dollars.

At the end of the article last week, I spoke about how I reduced the fan speed and lowered the Mini S power limit to basically "silent" performance. Today, let's consider further what we can do with a machine like that in the audiophile sound room.

REVIEW: Beelink Mini S (Celeron N5095A 4C/4T CPU, 8GB DDR4 RAM, 256GB SSD) Mini-PC. (And E1DA Cosmos ADC follow-up: RIAA EQ & 768kHz.)

In the image above, we see the Beelink Mini S computer. I was sent this product from one of the distributors (thanks to MinixPC - see here for the current price) for an honest opinion in the context of the fact that over the last while, I had already explored the small MeLE Quieter2Q and Quieter3Q as well as the more powerful AMD-based Beelink SER4 Ryzen 7 machines. 

Now, unlike the MeLE Quieter machines, this one is not fanless, but it is indeed quiet and I suspect the fan noise will be no problem in the vast majority of settings. On balance however, what you get is a machine that is less expensive (you should be able to find one for around US$180 or better) and the active cooling will keep it cooler especially if you do end up placing it in more cramped environments. As usual, make sure there is still air flow of course!

Let's have a closer look at the item and performance...

MEASUREMENTS: "CheapDAC'22" - Cheapest DAC in 2022? US$3.57 S/PDIF DAC from AliExpress. (Does objective analysis correlate with sound quality? Of course! And Lavorgna's DUT comment - "HiFi" is not art.)

"CheapDAC'22" - box, pamphlet, optical cable, USB 5V power cable.

While we've recently been examining high performance, high-fidelity DACs with amazing measurements, once awhile, I think it is good to have a peek at what "low-end" performance looks and sounds like. All the more important I think because audiophile magazines and "high end" online sites often seem to be reviewing increasingly more expensive "bling" these days, typically with just subjective comments. Needless to say, many expensive products do not appear to actually improve fidelity even if externally they might look great.

BigGuy in July pointed out to me one of the cheapest DAC packages ever seen on AliExpress - US$3.57; no tax, free shipping, arrived from China in about 5 weeks! For simplicity and lack of a better name, let's just call this generic device the "CheapDAC'22" (for 2022).

[With inflation lately, I see the price has increased since July as of this writing.]

The DAC is capable of both S/PDIF (Coaxial + TosLink) and Bluetooth input even (appears to be basically SBC codec, nothing fancy). The advertising even mentions 24/192 input.

Well, at this price, how could I resist not giving it a listen/test dear music lovers and audiophiles!? :-)

Aquantia/Marvell AQC107 10GbE Network Cards (eg. ASUS XG-C1001C): Driver and Firmware updates and improving stability. (And more audiophile ethernet snake oil warnings.)

While this blog is primarily about audiophile stuff, over the years I have discussed modern audiophile systems including thoughts on networks. Like it or not, computer audio/video is ubiquitous and probably has become the primary source of access for many of us these days (rather than deal with physical media). Furthermore, a fast, responsive, reliable home network is almost essential as a foundational "utility" for entertainment and work. As discussed back in 2018, I've been running 10 gigabit/s home ethernet (standard copper RJ45 Cat-5e/6) with an update to the ASUS router and QNAP switch infrastructure in 2021.

In 2022, when it comes to very high-speed computer network cards, the Aquantia/Marvell AQtion AQC107 chipset devices remain attractive due to reasonable price, PCIe 3.0 x4 compatibility, and ability to run at 2.5/5 gigabit intermediate speeds (also dropping down to 1Gbps and 100Mbps as needed of course). Over the years, I've seen comments online with frustrations around the popular cards like my ASUS XG-C1001C shown above. The issues are typically described as episodic disconnects usually for about 5 seconds (discussed here, here) and then coming back online. As you can imagine, this will lead to a time-out of network transmissions.

Depending on the application, this might or might not lead to problems. For audio and videophiles, this is a problem when we're streaming video to something like an AppleTV or playing music off Roon in real-time. Other apps may be more tolerant and can just wait a little longer and retry.

HOW-TO: Roon 2.0 with ARC released, running Android ARC on Windows. Roon's "grace period". And how about more audiophile remasters of music from the '80s onward?

The big news this week among the audiophile channels I think is that Roon 2.0 has been released which allows remote access to your Roon Core when on-the-go. Nice, it's about time considering that I've been streaming off Logitech Media Server for ages to my phone and at the office! The app that allows access remotely is something called Roon ARC - available for 64-bit Android in Google Store and for Apple devices.

This is a nice step forward and now I can listen to my music on the smartphone. However, I want to also play the music at my office on the Windows 10 computer. However, when remote desktop streaming was discussed with the company, the official answer has been "Roon ARC is mobile device-only application". Well, that's not a completely acceptable answer, I'm afraid. :-(

For the time being, you could run the Android app in Windows with BlueStacks 5 - 64-bit Android 9 Pie edition. Here's a look...

MUSINGS: Regarding the MoFiGate class action document, the love of analogue master tapes (on recent Bernie Grundman interview), and reminder of digital developments. [Yes, Canadian iPhone 14 still has hardware SIM tray.]

There are "hot topic" debates that stand the test of time, never truly resolved as it were. Typically, these debates are arguments of subjective ideologies (thus never fully resolved even if some elements can be shown to be clearly false) rather than explorations of nuanced facts. The "Analogue vs. Digital - which is best?" debate remains popular among audiophiles since the dawn of CD consumer audio in the early 1980's. As if there is ever only one single answer to such a broad topic with various pros and cons. I suspect most of us these days have grown at least a little tiresome of the topic even if we recognize that this "issue" will inevitably arise along our audiophile journeys interacting with others.

In the last while, there have been items in the news related to analogue audio, and by extension this whole debate, I think worth examining honestly. Let's spend some time to talk about this, consider some facts, and address a few of the unsubstantiated beliefs often perpetuated even among some respected members in the audiophile pursuit.

RETRO: Beyerdynamic DT 990, 600Ω, classic open-back circumaural headphones (circa 1991).

This week, I thought I would do a "retro" measurement of and listen to a headphone from the days of the Cold War. ;-)

Above, you see the 600Ω impedance Beyerdynamic DT 990 (forefather of the current DT 990 Pro, ~US$150), a pair of headphones lent to me by my buddy linnrd that he has had in his archives of audio equipment for quite awhile. As you can see on the box, these were made in W. Germany and purchased back in 1991, a couple of years after the fall of the Berlin Wall; either in Düsseldorf or nearby Essen I was told. The history of these headphones began back in 1981.

For headphones of this vintage (>30 years old), they are in great shape although in the image above, notice that I had replaced what used to be a thin layer of disintegrating black foam inside the earpiece with some bluish 1.5mm felt which I had used in my Dekoni Blue mod last year. So, not exactly a "stock" unit but pretty close.

As We Hear It: An audiophile comments on the Taiko Audio computer. The Mark Jenkins / Antipodes Audio Darko interview. On MoFi's One-Step DSD. And optical HDMI.

German "ear horns" circa 1917.

It's great to look inside my mail bag and post comments or questions here from readers once awhile. I must say that the clarity of thought and insight from readers have been inspiring over the years.

With permission, here's a comment from an audiophile in Europe regarding his direct experience with the Taiko Audio SGM Extreme "audiophile" computer server/streamer.

Since this reader has quite a unique high end system which can be easily traced, this message has been anonymized in a number of ways. Without further ado, a comment from SonicDeepThroat (SonicDT):

Received: July 2022 

Hi Archimago,

I thought I'd drop you a line as I found your blog post about the Taiko SGM Extreme very interesting. I auditioned this machine a few days ago and thought I would share my conclusions with you. (I tried to leave a comment on the relevant blog post, but Google wouldn't let me sign in to do so.)

REVIEW: Sabaj A20d 2022 Version DAC [Part III] - DSD, Headphone Out, AMPT, Subjective Impressions and Summary. (And some more Peru pictures!)

Okay, we're in the final stretch of my measurements/review series on the Sabaj A20d 2022 DAC. This time, let's finish with some measurements around DSD performance, the headphone amp output quality, and let's talk about subjective listening impressions before the final summary on my impressions of the device. (See Part I and Part II for earlier instalments in this review.)

REVIEW: Sabaj A20d 2022 Version DAC [Part II] - Resolution & Distortion. (Windows 11 22H2 available. Greetings from Peru!)

Let's continue our discussion of the Sabaj A20d 2022 today as we dive into the core of  the DAC's PCM resolution characteristics. You might want to review Part I as I had discussed much about the hardware itself, the filter options for the device, and jitter already.

REVIEW: Sabaj A20d 2022 Version DAC (ESS ES9038PRO) [Part I] - Hardware, Filters, and Jitter.

[Disclosure: Most of the products I review have been purchased personally or loaned from friends. On occasion, a manufacturer or seller will contact me about a device which I might have an interest in. This Sabaj DAC is one such device which was sent to me from the company for an honest, independent review. As I have done over the years, my review process focuses mostly on objective performance with some subjective listening opinions. Objective data rather than pure subjectivity I believe will help substantially mitigate bias.]

Over the last few years, we have seen an impressive proliferation of high resolution DACs at very reasonable price points coming from audio companies in China. In the world of consumer electronics, this should surprise nobody given that much of our technological products hail from that part of the world. Everything from Apple phones, to computer motherboards, to high-tech multinationals like AMD and Intel having manufacturing and assembly lines there.

On the test bench, we have the Sabaj A20d 2022 Version (currently ~US$420). Make sure to take note of the "2022 Version" because there is also the original A20d "2021 version" which clearly looks very different, does not feature headphone outputs, but is also based on the flagship ES9038PRO chip.

At the heart of this DAC, the ESS ES9038PRO is aided by the ES9311 "ultra-low noise" linear regulator to provide reference voltage to the DAC. Headphone amplifier is based on the TI TPA6120A2.

As I have been doing in the last year (like with the Topping D90SE, and S.M.S.L. DO100 previously) I think it's good taking my time with multi-part reviews to examine the various facets of these modern devices. Unlike back in the "old days" of digital where CD players only handled 16/44.1 content, modern DACs provide a whole host of samplerates, PCM + DSD, filtering options, potential noise and jitter variation, headphone output and input options typically USB and S/PDIF variants; even with these tests, as an audiophile who prioritizes sound quality, I haven't even seriously examined the Bluetooth audio options available in these devices over the years.

REVIEW: iFi GO Bar - Portable DAC / Headphone Amp (Cirrus Logic DAC, Balanced & Unbalanced).

My friend AudioPhil is really into his headphone gear. Recently he acquired the product above and asked if I might want to play with this for a few days... Sure, this looks interesting!

This is the new iFi GO bar (around US$320), a portable headphone DAC/amp. The USB interface is a USB-C form factor (480Mbps USB2.0 Hi-Speed), and there are outputs for single-ended/unbalanced 3.5mm TRS and balanced 4.4mm pentaconn. Interestingly, the company (iFi, subsidiary of AMR/Abbingdon Music Research) does not specify which DAC chip is used inside. Suspicion is that it's likely the Cirrus Logic CS43198 or CS43131, both are recent chips circa 2017 capable of "pseudo-differential" outputs and low-power consumption <40mW with rated THD+N of -115dB, DR 130dB, maximum PCM 32/384, and DSD256. The specs look good but don't get too excited about these ideal numbers when implemented in a USB dongle.

I don't know what's the point of being so secretive about the DAC chip used (Crutchfield says it's the 43131).

Pacific Audio Fest 2022 (PAF 2022) - Concluding observations and thoughts... (MoFi One-Step DSD controversy, and a few videos!)

Well, the first PAF 2022 is now in the record books (see Day 1 and Day 2 for context). I honestly hope that the organizers, companies showing off their goods, and attendees all had a great time. I regret not getting the RMAF2019 T-shirt so made sure to grab one this time around and will wear it with pride among fellow audiophiles. ;-)

As I was driving home to Vancouver, BC, I was thinking about audio shows in general and also specifically about the PAF... What was seen, the experience of these shows as an audiophile, stuff like that.

Pacific Audio Fest 2022 (PAF 2022) - Day 2

The elevators heading up to the 13th & 14th floors of the PAF, and a view from elevator. Glorious hot 25-30°C weekend. IMO, we who live in the N.W. / Western Canada should never complain of the few days we get every year of the heat! So long as we don't hit closer to 40°C like last year's "heat dome"...

In total, I spent 2 days at Pacific Audio Fest 2022. The pictures and comments here will cover some of what I saw and general impressions for those rooms. See the Day 1 post as well.

Let's get going!

Pacific Audio Fest 2022 (PAF 2022) - Day 1

Hey there everyone, it's Pacific Audio Fest 2022 time here in Seattle! Since it was just a 3-hour drive from home in Vancouver, I figure it would be fun to check out the inaugural PAF this year. The last time I was at an audio show was back in 2019 for what would become the last Rocky Mountain Audio Fest - who knew!

My understanding is that PAF under the direction of Lou Hinkley brings with it experience from Capital Audio Fest held in Washington DC (which will be held this year November 11-13).

I think the audio geeks here in the Pacific Northwest and Western Canada appreciates the availability of an easily-accessible show in this part of the world to check out and listen to some of the latest (and greatest) the industry has on offer.

Summer Musings: On Stereophile's "Quackery, Gullibility, and Open-mindedness". Nature of audio devices. Truths in audio (and medicine).

Well ladies and gents, I guess it's official. Stereophile, at least in part, is not a journalistic venture based on a recent "My Back Pages" article. In the opening 3 paragraphs of "Quackery, Gullibility, and Open-mindedness", Rogier van Bakel basically discards the importance of skepticism as a journalist, and seems to set the stage for audiophiles to accept basically all manners of quackery and snake oil.

For those who have been on this blog over the years, you probably know that I'm a physician working here in Vancouver, Canada. I write these audio musings and technical review articles as part of my audio hobby/journey to go beyond enjoying the music as a consumer, towards further understanding of how the technologies work, with the hope that the results of the explorations may be helpful for other pilgrims along this path as we discuss hardware and improving sonic fidelity.

On quiet evenings when the kids are asleep and my wife is enjoying her TV dramas, examination of electrical devices and their waveforms can provide a much-needed distraction from the marvelous yet frequently incomprehensible complexity of human physical and mental states.

REVIEW: MeLE Quieter3Q (Celeron N5105, 8GB DDR4, 256GB eMMC) MiniPC: Fanless, 4K/HDR streaming. Getting closer! (Thoughts on Apple's M1 Mini as HTPC.)

Yeah, that's an old XBOX 360 Kinect camera back there! Hey, there are cool things you can do with this as a 3D scanner...

Greetings ladies and gents. In the posts for both the MeLE Quieter2Q post as well as just last week with the Beelink SER4 Ryzen 7 4700U computer review (BTW, I added an addendum - HDR10 works on that machine), I noticed questions, comments, and E-mails about utilization of these MiniPCs in the home theater setting; specifically video and HDR features.

Recently, I saw the availability of the MeLE Quieter3Q fanless MiniPC (currently around US$250). With the various feature upgrades, I figure that this is one which might qualify as a reasonable HTPC computer given that it features HDR video capabilities and a bit more CPU processing power. As such, I decided to take it for a spin. I bought the slightly more expensive 256GB eMMC storage model; since I am targeting video playback, it might be nice to have some extra storage for local data.

Much of what I said about the Quieter2Q applies here, so let's focus on performance differences and discuss this machine as a video streamer beyond audio purposes...

REVIEW: Beelink SER4 Ryzen 7 4700U (8C/8T) MiniPC - A small, quiet, fast, general "workhorse" PC... [Addendum: HDR works.]

These days, if we look around most homes, I think we'll see all kinds of computers used for different purposes in the rooms. I've talked about my main Workstation, the Server machine, even my Gaming rig a number of years back (much of that upgraded since). And a few months ago, we talked about the very low power fanless Celeron MeLE Quieter2Q which functions as a very stable stereo/multichannel streamer for Roon.

[BTW, there is an upgraded MeLE Quieter3Q now which is faster by ~30-40% featuring the Celeron N5105 processor for a few more dollars, but still no AVX2 if you're thinking about Windows HQPlayer as discussed here.]

Recently, I've been wanting to upgrade my 2016 Intel NUC 6i5SYH which in the last few years has been the heart of the audio measurements rig. Over time, as my measurement regimen has become more detailed, often using larger FFTs parameters, once awhile, I've started noticing that the old i5 CPU isn't keeping up with the processing needs and this shows up as glitches in the data such as when running multichannel REW "stepped sine" captures. Obviously, this will not do. ;-)

To remedy the situation, I got one of these Beelink SER4 Ryzen 7 4700U-based MiniPCs (8-core, 8-threads, currently less than US$450 for the 16GB RAM/512GB M.2 SSD model). There is also a more expensive SER4 with faster 4800U processor (8-core, 16-threads) if you need that extra speed.

This machine was purchased from standard retail channels; this review was not sponsored in any way.

Hi-Res THD(+N) vs. Output Level Measurements (ESS "HyperStream" vs. AKM vs. TI/Burr-Brown). And a bonus R-2R!

Notice last time as I ended off the post, I showed what I think is an interesting "high resolution" graph of THD(+N) vs. Output Level for the Topping D10 Balanced which uses the ESS ES9038Q2M chip. This was spurred on after some discussions on glitches and anomalies one might see due to the "HyperStream" architecture of the ESS chip.

These days, other than the occasional fully multibit or discrete R-2R DACs, the vast majority of what we're using are multibit/multilevel sigma-delta devices. This includes the brands I have listed in the upper graphic; Asahi Kasei Microdevices (AKM), ESS Technology, and Burr-Brown (which was acquired by Texas Instruments in 2000). We'll also talk about the Philips later. ;-)

Today, let's have a look at "high res" THD(+N) vs. Output graphs (XLR output where possible to keep noise as low as possible) comparing different DACs from these companies...

REVIEW: S.M.S.L. DO100 DAC [Part III - DSD, Subjective, AMPT Recording, and Conclusions]. And a very close look at the Topping D10 Balanced THD(+N) vs. Level graph.

As you can see, the SMSL DO100 displays DSD samplerate in the form of DSD64 (64 x 44.1kHz = 2.8MHz), DSD128 (5.6MHz), DSD256 (11.3MHz) and DSD512 (22.6MHz).

Okay audiophile friends, let's finish off the trilogy of posts on the S.M.S.L. DO100 DAC with some final measurements around DSD performance, let's talk about subjective listening impressions, and as usual, let me provide a direct recording from the XLR output for comparison with others I have done (as discussed here).

We'll then put this all together as final concluding thoughts on this device.

Notes on DAC DSD (1-bit PDM) measurements going forward...

In the early 2000's, we witnessed the battle over hi-res audio in the form of SACD vs. DVD-A. SACD, the brainchild of Sony, utilized a 1-bit Pulse Density Modulation (PDM) method they called DSD (an advertising term) whereas DVD-A had the ability to store up to 24-bit, 192kHz Pulse Code Modulated (PCM) digital audio data (multichannel up to 24/96).

From the beginning, there were concerns about this push towards 1-bit systems into the consumer space along with claims that 1-bit PDM should form some kind of archival foundation for music. There were critics include Lipshitz and Vanderkooy - see their paper "Why Professional 1-Bit Sigma-Delta Conversion is a Bad Idea" from the September 2000 AES. And the next year in May 2001, they followed up with "Why 1-Bit Sigma-Delta Conversion is Unsuitable for High-Quality Applications". Even Bob Stuart chimed in on the unsuitability of DSD for "high-resolution audio" back in 2004. This is no surprise since Meridian was firmly with DVD-A including developing the MLP compression system which subsequently has been licensed by Dolby and renamed TrueHD; it looks like Dolby and Meridian had an arrangement dating back even to 1998.

These concerns around fidelity and the unsuitability of 1-bit PDM as an editable format in audio production are why in the professional world, we see audio recorded and edited in 24/352.8 "DXD" and Sony's own "DSD-Wide" (8-bit/2.8MHz) instead of DSD64/1-bit "DSD-Narrow".

While this was playing out in the academic/professional arena, the advertising industry including the "mainstream audiophile media" championed DSD and published all kinds of flowery words suggesting how it sounded "more natural", or "analogue-like" compared to PCM. While I don't think we can put an exact date on when DVD-Audio officially died as a viable commercial product, I think by 2005 it was quite clear that hi-res physical formats were not going to be mainstream and DVD-A did not have the number of titles available compared to SACD. My sense is that the hybrid-SACD feature with both DSD and CD-compatible layers was a major differentiating factor that has resulted in still a trickle of SACDs released these days.

I'm bring this stuff up now as an extension to the discussions around SoX-DSD and the Philips Test SACD articles last year during my series on the Topping D90SE review because I've been thinking about how best to standardize the DSD test signals I use when testing. Different DACs tend to handle DSD playback differently and I wanted to make sure that my test signal parameters are at least somewhat in line with the music encoded on an SACD or maybe DSD128 download these days.

REVIEW: S.M.S.L. DO100 DAC [Part II - PCM Resolution]. (And on MQA's distasteful environmental claims...)

As we continue to evaluate the S.M.S.L. DO100 DAC, let's spend time today delving into the resolution that this machine provides as a PCM DAC (see Part I last week for filters and jitter performance). Given that PCM is the de facto digital modulation scheme, this post will form the heart of DAC performance evaluations. We'll leave DSD to Part III along with discussions of subjective performance.

With PCM data, this DAC will accept up to 32/768. Let's run some tests as per usual to see how this device compares to others I've looked at on this blog. For most of the tests, I will use my Raspberry Pi 4 "Touch" (USB) or a Logitech Squeezebox Touch (S/PDIF) as digital source. The E1DA Cosmos ADC will be used with or without the Cosmos APU to measure. For some of the REW-based tests, I will perform a simple loopback that looks like this:

Intel NUC → SMSL DO100 DAC → [Cosmos APU] → Cosmos ADC → Intel NUC

As usual, all cables are generic RCA when testing unbalanced, for XLR measurements 6' Monoprice Stage Rights were used.

Unless otherwise noted, the DO100 will be set-up to use "FL6" Linear Steep filter.

Without further ado, let's jump to it...

REVIEW: S.M.S.L. DO100 DAC (dual ESS ES9038Q2M) [Part I - Overview, Filters & Jitter]. (And the likely continued contraction of MQA...)

Over the last number of years, we have seen a proliferation of DACs from Chinese manufacturers offering models of increasingly better resolution - higher fidelity - and greater feature set. These days, I am of the opinion that we have achieved way above and beyond the ability for human hearing to differentiate these machines unless the manufacturers purposely added some kind of "coloration" to the analogue output whether it be frequency response or changes to the noise and distortion levels (the "tube sound" being a prototypical example we may come across).

As you can see in the image above, we have the S.M.S.L. DO100 DAC (~US$250) in today for review. I bought this unit through retail channels and intend to either use it myself or give it away if I have no need for it.

For many devices these days, opening the manual will show us technical information like the frequency response of the filters in this example. I think this is a nice evolution among manufacturers recognizing that showing product performance is important to educated customers with graphs and technical details rather than mere prose which often provides little satisfaction for the consumer's intellect.

Today, let's start a multi-part look at this DAC; no need to hurry because I think the performance at this price point warrants serious consideration and the many ways and features one can gather performance metrics on (I don't promise to test everything of course!). Obviously it's not an expensive device, has a remote controller, has both unbalanced RCA and balanced XLR outputs, Bluetooth 5.0 input, capable of up to 32/768 PCM and DSD512 (1-bit, 22.6MHz) using USB 2.0, along with S/PDIF TosLink and Coaxial inputs for up to 24/192 and DoP DSD64. No money wasted on MQA licensing. Depending on what we find, this might be right for you...

MUSINGS: The hunt for -150dB THD with the Victor's 1kHz Oscillator; A look at Paul K.'s Multitone Loopback Analyzer; And the pinnacle of audio streamer pricing? The Wadax Atlantis Reference Server. (And REW IMD vs. Level Step!)

I like a good challenge ;-). A few weeks ago, in my post on the E1DA Cosmos APU, in the comments, MG discussed achieving THD -155dB on the Victor's Oscillator! In my original post, I showed a picture of -141dB. Subsequently, I then fiddled around with the set-up and achieved around -148dB.

Well, on one of my lazy afternoons, I thought I might as well give this another try. The aim - at least THD of -150dB. So I packed up some parts I needed and moved it into the quietest room (electrically and acoustically) in my house. Bits and pieces laid out on my ottoman where I place drinks on late night listening sessions. ;-)

Clearly this would have to be run off battery power to remove any mains hum. I went with my trusty RME ADI-2 Pro FS ADC, powered by a 12V/8300mAh TalentCell lithium battery pack for convenience in case I needed to fool around with input voltage settings. The E1DA Cosmos APU was powered with a 5V battery pack.

A Look at ADC Noise Limits and Distortion - Or "How much difference does the Cosmos APU make?" And a look at 2-channel Room EQ Wizard measurements!

I received a few questions as a follow-up to last week's post about the E1DA Cosmos APU basically around the question: "When do I need a pre-amp/notch filter like that if I have a high resolution ADC?"

That's a great question! Let's spend some time looking into this...

Now, the first thing to be mindful of is that our DACs and ADCs are not perfectly linear devices, nor have limitless low-noise performance of course. This is why we measure the limits of DACs to gauge the extent of "accuracy". And ADCs likewise have limits as well to their intrinsic noise level and potential for distortion. As we approach the limit of the ADC's performance, it will start introducing its own characteristics into the captured signal which could look like noise anomalies as well as harmonics - like DACs, there is an ADC THD+N.

In this post, let's run some practical "experiments" of sorts using the Cosmos ADC and RME ADI-2 Pro FS to examine these ADC limits when measuring DAC dynamic range and THD+N/SINAD with and without the aid of the Cosmos APU.

EARLY LOOK: E1DA Cosmos APU - high performance, low-noise pre-amp and 1/10kHz notch filter. [Quick peek - S.M.S.L. DO100 DAC.]

Readers on the blog will likely remember that last year, Ivan Khlyupin (aka IVX on a number of forums) of E1DA sent me a pre-production Cosmos ADC for testing and use. As discussed then, this affordable ADC unit turned out to be a remarkably capable device using the ESS Sabre ES9822Pro chip at a very reasonable price. With recent price upheavals, currently on Amazon for a Grade B device with SNR 127+/-1dB(A) in mono mode, it's selling for just less than US$250.

There were already discussions last year that the "Cosmos" line of devices would include the one we'll be talking about today - the Cosmos Analog Processing Unit (APU). As the name implies, this is an analogue device that serves the purpose of (pre)amplification with very low noise, also providing a 1kHz notch for accurate measurements of THD+N/SINAD as we typically see in DAC reviews.

With the APU near production release (possibly next month or so), Ivan again kindly sent me a unit for use here on the blog. Using the combination of Cosmos APU + good ADC (doesn't have to be Cosmos ADC), the user should be able to peer down into the noise limits and measure characteristics like dynamic range, and THD+N/SINAD with great accuracy even beyond the limits of modern state-of-the-art DACs.

DEMO: Software de-clipping of dynamically compressed recordings (Red Hot Chili Peppers' Unlimited Love). On "Why you can't trust audio measurements". And "Those Obscure Objects of Desire" - Utility and Luxury.

Let's get right to the heart of the issue with the diagram above!

There have been discussions among audio sites like Audiophile Style and Darko Audio that this latest album from RHCP - Unlimited Love (2022, average DR7) - is their most "audiophile-friendly". 

Flea, the band's bassist, tweeted on April 1st (hope not meant to be April Fools' joke!):

“For you audiophiles out there, the new RHCP record is mastered directly from the tape we recorded it on, no computers, no lame compression or limiters”

In the image above, I extracted the last minute from track 1 ("Black Summer"), a portion of the music which is quite loud for a peek at the waveform. One look at the original data clearly shows that the music has gone through a compression step at some point in order to create that "flat top" DR5 in the image above. Flea is wrong.

Whether this happened in the recording, mixing, or mastering steps, who knows. The clear use of dynamic compression is present in both the 24/96 version and on the CD. Clearly, music like this does not benefit from the "hi-res" 24/96 version so I would recommend saving your money if you're tempted to purchase a download. As usual, be critical when buying hi-res.

REVIEW / MEASUREMENTS: CCA (Clear Concept Audio) C12 IEM - 1 Dynamic + 5 Balanced Armature Drivers - are more drivers better? (Plus new analogue disc technology, cable-maker Russ Andrews interview.)

Earlier this month, as I was preparing the final write-up for the KZ ZSN Pro review, I was impressed enough by the performance of those very inexpensive IEMs (less than US$25) to go ahead and grab these CCA (Clear Concept Audio) C12 (US$50) earphones to see how an upgrade at twice the price would perform in both listening and measurements. Note that CCA is a related company to KZ so when we look at the open-box image above, we see that the contents are similar. We have this time a braided ear-loop cable (that's still easy to get tangled), also 1.2m in length, a couple of info pamphlets, 3 extra sets of silicone ear pieces, same as the KZ ZSN Pro.

At twice the price of the KZ, the hope here is that these would represent a significant sonic upgrade across a number of domains. On the surface, a major talking point for these headphones is that they consist of a more complex arrangement of drivers which in theory could provide more accurate coverage across the audible frequencies. Drivers in each earphone include a single larger 10mm dual-magnet dynamic/moving coil driver, and 5 small balanced armatures (two of which are reported as Knowles 30095, not sure the others). So that's a total of 6 drivers per ear piece, 12 both sides - hence "C12".

 

MUSINGS: Myths, clichés and Hi-Fi+'s Taiko Audio SGM Extreme computer review. A hypothetical fast, fanless audio computer build. And "channels/bit-depth/samplerate" labeling convention - a suggestion.

"Nowadays people know the price of everything and the value of nothing."

-- Oscar Wilde, The Picture of Dorian Gray, 1890

Once awhile, we in the audio world run into devices that are so ludicrous that it becomes somewhat entertaining reading or watching reviews about them. Like Super Bowl ads, the advertising can be fascinating in themselves regardless of whether you care about or even know how to play American football. The Dutch Taiko Audio SGM Extreme is such a product which I find fascinating - not because the technology is all that mind-blowing (server CPUs, Optane storage, large SSDs, big fanless case) - but in seeing what they're trying to do with the "spin" around the product to try to justify an asking price! (Previously, I've referenced the device in a related discussion as well.)

I thought it was interesting reading this recent Hi-Fi+ review by Alan Sircom and examining the claims. Just because a review might be written in a "subjective" fashion doesn't mean readers can't or should not be critical about the beliefs expressed. To a certain extent, I believe it is the responsibility of "rational audiophiles" to push back against the nonsensical, even mythical, ramblings of certain subjective, supposedly honest, viewpoints. I agree with T.S. Gnu, typically we cannot expect magazine writers to be bluntly honest in today's environment.

For those unaware, The Absolute Sound (North America) and Hi-Fi+ (UK) are glossy, subjective-only, sister publications that IMO read like the unabashed advertising arm of the "high end" industry. Over the years, TAS & Hi-Fi+ have advocated snake-oil of all sorts and TAS even published pseudo-science articles purporting to be empirical research (look up the articles from Charles Zeilig and Jay Clawson around 2011 - I've mentioned this back in the day, and here's an example of what they do/say).

REVIEW / MEASUREMENTS: KZ ZSN Pro - very inexpensive dynamic + balanced armature IEM. (And the importance of the audiophile "low end" and meaningful succession.)

Since I believe much of high-fidelity audio is already "mature" technology, these days a lot of what I find interesting are products that either present new features for the music lover (and audiophile), or devices that are of high value. In a present era of inflation and energy price shocks, "value" I think for most people has become even more important into the foreseeable future. As discussed in the past, the price of luxury items is usually a reflection of non-utilitarian benefits rather than actual sonic fidelity; that is basically the epitome of the "high end" moniker, behind which, much snake oil is allowed to thrive.

In this post, let's have a look and listen at an IEM which I think absolutely represents a member of the "high value" class of products! At less than US$25, the KZ "Knowledge Zenith" ZSN Pro IEM is at a price point that anyone can afford if you're in the market for some wired headphones these days (funny the designation "Pro" for something in this price point!). Considering the wide range of prices for headphones, it's the kind of thing you can throw in your travel bag and not worry if they get damaged.

The question of course is how do these sound!? Let's take a deeper dive into this...

MEASUREMENTS: 1MORE Quad Driver IEM (E1010)

For the post this week, let's have a look at the 1MORE Quad Driver IEM (~US$150 these days). These have been out for awhile; released in mid-2017 I believe. The specs on these are quite interesting given the asking price. Driver configuration seems complex with single dynamic driver and 3 balanced armature units within the relatively small capsule. The dynamic driver is advertised as being some kind of "diamond-like carbon" (DLC) that covers bass and mids with the balanced armature units filling in at the higher frequencies based on the advertising material.

Furthermore, the headphone also has an integrated volume/playback control as well as a microphone when making calls.

The brand also prides itself on this being the world's first "THX Certified Headphone". I'm not sure exactly what that certification means; presumably some combination of testing to ensure low distortion and frequency response thresholds must be in the mix.

DEMO: Tears For Fears - "No Small Thing" - Low-DR CD vs. Higher-DR Steven Wilson 5.1 Downmix to 2.0 (and the obvious importance of audio production quality)

Despite all the examinations of what often amounts to subtle differences in sound when we compare different hardware devices, I think as audiophiles we too often neglect the very significant differences that mixing and mastering makes.

Recently, I received my copy of Tears for Fears' The Tipping Point, the Blu-Ray only available for order online here. As you can see in the image above (screenshot of the menu), the disc includes both lossless DTS-HD Master Audio 5.1 and Dolby TrueHD-Atmos mixes done by Steve Wilson.

I believe you can already stream the Atmos mix over Apple Music "Spatial Audio" but that would be in lossy Dolby EAC3+Atmos. As you can imagine, the multichannel mix sounds quite different from the 2-channel CD/lossless stream!

MEASUREMENTS: Topping HS01 - USB 2.0 Isolator & Ground Loop Eliminator (and a listen to Santana's "Blessings and Miracles")

Hey everyone, as you might be aware, I'm not a fan of USB "doohickeys" in general use. You know, all those USB boxes that are supposed to clean up your signal, or maybe reduce jitter, or "regenerate" this and that. Especially if you're not sure if you actually need it; some of these devices cost hundreds of dollars. On the lower price end, I had a look at the AudioQuest JitterBug FMJ last year which was a rather disappointing product.

Having said this, there are devices that can provide benefits like USB isolation for things like DACs. For example, the USB1 inexpensive ADuM4160 devices like this Nobsound ADuM4160. The problem is that this is only operating up to USB1 12Mbps "full speed". Furthermore, one would be limited to 24/96 performance even if the device is able to fall back and negotiate as USB Audio Class 1.

Enter the Topping HS01 (~US$70), a little black metal USB2.0 box advertised as providing galvanic isolation (to 1kVrms), for data and power lines with USB-B (to computer), and USB-A (to audio device) ends. Furthermore, there's a USB-C plug for devices that need extra power.

[Note: This device is not compatible with USB1.0/1.1. So don't be plugging in keyboards and mice to this. Non-audio devices like USB2 memory sticks and even my smart phone were fine. I have not tried plugging a USB2 hub up to this point so there might be issues there.]

MEASUREMENTS: Etymotic ER-4B - "Classic" In-Ear Monitor (IEM) / "Canalphone".

Nice box with accessories. Can't see it well in this picture but in the middle of the box is a small container of "damper"/"filters" and tool to aid in replacement when clogged.

Today, I want to expand the measurements of headphone-type devices to include examination of in-ear monitors. As usual, before posting measurements on a range of devices, I believe it's important to set the ground work as to how it's being done and to what relative "standard". I believe this is useful because when I use subjective descriptions, I think it's always nice to refer to context on the objective side. I have seen numerous reviews use things like star ratings or sometimes seemingly arbitrary "3.5/5"-type scores, but without more concrete, specific examples, often the reader is left without a sense of actually what is being described nor have a "hat to hang on to" when talking about relative differences with another product the reviewer might also be pointing to.

Similar to the AKG K371 back in April 2021 as a discussion of headphone measurements for circumaural (and supraaural) devices, today, I want to focus on one of the first IEM-type (In-Ear Monitor, also called "canalphone") transducers I bought back in the early 2000's. This is the classic noise-isolating Etymotic (often stylized as Etymōtic) ER-4B microPro Earphone. The very first ER-4 came out in 1991 and I believe the 4B version I have is reflective of the intent of that very first design.

While this specific ER-4B model has been discontinued for awhile now since early 2010s, there are still a number of ER-4 series products out there including the ER-4XR ("eXtended Response" meant for "music lovers" who want a bit more bass) and ER-4SR ("Studio Reference" for flatter frequency response). 

As suggested by the variants, Etymōtic makes these earphones for different target uses over the years. This '4B' model was meant for technically accurate "Binaural" monitoring purposes. Etymotic aimed for a flat response that follows a "diffuse field" target (great discussion here on the different targets BTW).