Saturday, 21 November 2020

On "Measurements, Listening, and What Matters in Audio" by Robert E. Greene, with unfortunate Robert Harley "counterpoint".

It has been a busy week, so alas, I didn't get a chance to finish some recent measurements in time for the weekend. Will aim for next week!

The other day, I read Robert E. Greene's editorial on The Absolute Sound's webpage titled "Measurements, Listening, and What Matters in Audio". Nice, I didn't think I would ever read such coherent introspection in those (virtual) pages. Probably also one of the first times I have seen the mainstream audio press willing to consider the "beginning of audio wisdom" (hat tip to Proverbs). Of course, seeking wisdom plus achieving a more rational basis in this hobby are overarching themes in many of the articles on this blog. So too, Greene's reference to concentrating on the "fundamentals", the foundation of acoustics whether it be in the production chain (ie. "microphones") or the reproduction/perception system (ie. especially "speakers and their room interactions") are not unfamiliar to readers here - we covered some of this earlier this year. Absolutely agree, Dr. Greene, including the part about "I think that almost everything in audio can be explained by measurements" is a fair and in these days, a very safe statement to make.

Wishing you good health.

Now as for Robert Harley's "counterpoint". Oh my... Surely Harley's ramblings cannot be the last words on this topic because clearly there are issues!

Saturday, 14 November 2020

MEASUREMENTS: S.M.S.L. SA300 - Infineon MERUS-based Class D desktop amplifier. (Screwed up New York Times - Wirecutter/Butterworth measurements/review?! And Klipsch on TIM.)

"BAS" on screen indicates I'm using the bass-boost EQ here.

Today, let's have a look at the little SMSL SA300 desktop amplifier I'm showing above sitting beside the Topping DX3 Pro V2 DAC (previously measured and reviewed here).

As mentioned previously, I found myself in the position of needing to update my computer workstation desktop speaker system. I figured, instead of staying with powered/active speakers, since I do have a few bookshelf speakers around the home, why not try some passives on the desktop as well?

While active speakers are great in that the built-in amplifiers and transducers can be well-matched and optimized, the ability to "mix-n-match" passive speakers while opening up the potential to upgrade amplifiers I think is fun for the hobbyist. As such, I found myself drawn to getting a small low-power Class D amplifier like this.

Since the amplifier will likely be left on 24/7, I wanted something that's highly efficient but provides adequate power. This SMSL device internally is powered by the Infineon Technologies MERUS MA12070 Class D amplifier which uses their "multi-level" modulation such that the switching output can have half-voltage levels which adds an extra level of control and power savings. The device is rated to provide up to 2x30W continuous into 8Ω or 2x80W into 4Ω but realize this is with 10% THD+N. What will be more interesting to me is how much power is available into something like 4Ω with ≤0.1% THD+N, and the noise this switching device produces. Let's see if this amp lives up to hopes of "high-fidelity" playback...

Saturday, 31 October 2020

qSpins: AudioEngine A2 & Edifier S2000 Mk III 2-Way Bookshelf Speakers

Hi everyone, thought I'd just publish a couple of "qSpins" today as I might be away for a little bit to attend to other duties in the next couple weeks.

In the last while, I've been looking at getting another pair of speakers on my computer workstation desktop. Here's basically what my desktop speaker system has looked like for years:

Saturday, 24 October 2020

MUSINGS/HOW-TO: Raspberry Pi 4 "Touch" Audio Streamer, and CRAAP settings! ;-) The decline of public feedback, virtual showrooms, value-added content and Darko Audio?

Left - Raspberry Pi 4B, Right - Raspberry Pi 3B. Heatsinks installed on both boards.

Back in August, I wrote an update on building and running the of Raspberry Pi "Touch" audio streamer with RoPieee software. The article was still written with the Raspberry Pi 3B(+) in mind.

Well, on Prime Day recently, I was able to get a Raspberry Pi 4, 4GB "Starter Kit" for a price I could not resist. It's nice to have all the parts including the appropriately sized heatsinks, ready-to-use microSD card, and 5V/3A USB-C power supply. For now, I have no need for the Pi 4 case and the micro-HDMI cables can go in my box of miscellaneous cables.

For audio streaming purposes, a basic 2GB Pi 4 kit (<US$55) would be even cheaper and works just as well. Given the minimal difference in cost, no point going with a 1GB model although that would still be fine - remember the Pi 3 was limited to 1GB. There is also an 8GB Pi 4 but that's a huge amount of memory for just an audio streaming "appliance"!

Saturday, 17 October 2020

Musings/Measurements: quasi-Spinorama "qSpin" & the KEF LS50 bookshelf loudspeaker...


Auditioning the KEF LS50 Black Edition, powered by SMSL SA300 Class D amp on computer workstation.

With autumn here, sunlight hours reduced and looking towards the rainy months ahead, I thought it would be good to start expanding measurements and be a bit more "serious" with evaluating loudspeakers.

As you know, speaker measurements have been done since the start of the audiophile hobby and there are all kinds of ways to get the job done to varying levels of precision and reliability. Stereophile has been doing this for years with John Atkinson's use of the MLSSA (DRA Labs) system as he summarized in this review which formed his 1997 AES paper. More recently, it's great to see Audio Science Review's use of the Klippel Near Field Scanner (NFS) for many speaker measurements already!

For many of us interested in speaker performance, probably introduced to the ideas with Floyd Toole's book Sound Reproduction - Loudspeakers and Rooms (first edition 2008, now in 3rd edition 2017), there has been a rise in loudspeaker measurements using the "Spinorama" technique. This measurement method plus its standard representation of data has since becoming codified in the ANSI/CTA-2034-A "Standard Method of Measurement for In-Home Loudspeakers" (you can get a copy of the current CTA-2034-A R-2020 here), first published in 2015.

Saturday, 10 October 2020

Further Explorations into "Intersample Overs" - Resampling/Downsampling & De-Clip by Charles King


Greetings everyone. It's great to interact with some of you over the years around contents I've posted in this blog. As you perhaps know, recently, I talked about resampling hi-res audio files in my article on "Post-Hi-Res" with the idea that the vast majority of albums we download as supposedly high-resolution content simply do not warrant the file size or bitrate. As such... I routinely just bring them back to 16/48 or 16/44.1.

Here's an interesting comment by Charles King on this and his explorations of the topic:

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Hi Archimago,

I was a bit taken aback on reading your 25 July post in which you talked about a need to guard against intersample overs when downsampling hires files. I've collected quite a few albums in hires over the years, often to check if I could hear any difference (I can't, and have given up on that) or to see if they provided better mastering (occasionally true, though in some notable cases the mastering is audibly worse). Since I don't want to litter my long-term storage with gigabytes of useless data I end up downsampling these to 16/48 in Adobe Audition (which is rated as having one of the better resamplers) and then compressing to variable-rate AAC (which is transparent to me).

Saturday, 3 October 2020

HOW-TO: CD Pre-Emphasis & Using SoX De-Emphasis. (And the decline of physical media with vinyl revenue > CD now.)


Have you ever ripped or downloaded an old music CD that just sounds way too harsh? Sounding like the EQ is accentuated with too much treble?

Back in the day, a number of CDs were processed with pre-emphasis used and we can see at least a partial list of pre-emphasized albums here. Typically these would be early CDs from the mid-'80s although as per the list there are also a number from the late '80s and even early '90s.

In those early years, DACs were incapable of true 16-bit resolution and noisy analogue brick-wall filters added high-frequency distortions. As a means of improving signal-to-noise, they boosted the high frequency content and corrected the tone on playback (see this Hydrogen Audio FAQ on Pre-emphasis). As you're probably aware, a CD doesn't just contain the 16/44.1 audio data but have encoded within each "frame" 8 bytes of CIRC error correction and another byte of "subcode" data which can be thought of as "control data"; like a precursor to today's much more complete metadata. One of the subcodes is the "pre-emphasis flag". When activated, a CD player will engage its "de-emphasis" circuitry/filter. These days, DAC chips themselves can implement digital de-emphasis as part of basic functionality.

Saturday, 26 September 2020

MEASUREMENTS: RME ADI-2 Pro FS R Black Edition as DAC.

 

Well friends, it's time to publish some measurements of my new RME ADI-2 Pro FS R Black Edition ("FS R BE") unit as DAC. For background, refer to the Preview from August and a couple weeks back, I had published results discussing the ADC function.

As you might be aware, since 2018, I've been using the older RME ADI-2 Pro FS ("Pro FS") for ADC and DAC duties in my measurements. It has performed like a champ and in fact, given that the ADC function is almost identical between the two units, there's certainly no reason to retire the "Pro FS" from measurement duties.

What we know is that as a DAC, the "FS R BE" should perform better than the "Pro FS" due to the fact that the internal AKM chip has been upgraded to the AK4493 from the previous AK4490. On paper, this represents a +5dB improvement in SNR and +1dB improvement in THD+N so we're not looking at Earth-shattering differences in specs numbers. Let's see if we're able to measure these differences on the test bench and identify any other changes to the DAC's performance along the way...

Saturday, 19 September 2020

As We Hear It: Thoughts from an audiophile friend on assembling his sound system.


Every so often, I have the pleasure of having friends and readers add their thoughts to these pages. The other day my buddy whom I visited at the end of 2019 (a.k.a. "linnrd" online) sent me this discussion piece. Back in December when I visited, I invited him to take the opportunity to write about his equipment and how he came to this interesting collection of gear. Well, he delivered...

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A Complex Path to Simple Sound


Audio systems are generally an assemblage of products from different manufacturers. While significant R&D resources go into designing the various pieces that make up a system, it is left to the consumer to deal with the "R&D" of system design from "soup to nuts", as it were. The popular audio press is more oriented to singing the praises of individual components instead of educating and helping the reader actually assemble a decent combination of the aforementioned. Perhaps this a result of whom they view as customer and who as the product. A graveyard visit allows one to see much touted wonders such as Shakti Stones and the green CD marker (Ed: also see Harley's extensive investigation in Stereophile in 2004 amounting to nothing of course), to name just two, with the rotting corpse of MQA lying in wait for a plot (in both senses of the word!). 

Unfortunately, the self-proclaimed experts actively ignore existing knowledge and science and make it extremely difficult to fix this fundamental problem of the spread of misinformation by also subscribing to junk science. In other words, they are really messing up the S:N ratio of information transmission. As Bill Whitlock from Jensen says, reiterated in a recent discussion: "It often feels like an uphill battle to educate in a world of marketing deception and self-appointed experts."

Saturday, 12 September 2020

MEASUREMENTS: RME ADI-2 Pro FS R Black Edition as ADC.


About a month ago, I posted this preview of the RME ADI-2 Pro FS R Black Edition AD/DA converter. It has been a wonderful month of simply listening to this device without a care around performing measurements. For listening, I have it set up as per the image in my sound room with the Raspberry Pi "Touch" running RoPieee previously discussed.

So far, from a subjective perspective, it has been a joy to listen to music with this machine.

Alas, as a "more objective" audiophile, it came time to have a look at the performance for this device to check if I'm missing any significant limitations. Over the years, I've discussed limitations to human hearing as well as the idea that many of our audio electronics these days have surpassed human auditory perception such that while measurements of DACs or amplifiers can show limitations, often these are beyond the resolution thresholds of human hearing/perception. Remember that while not all measurable anomalies need to be chased after when the goal is simply to be able to enjoy music, technical "ideals" are useful for devices one may want to use as a "reference".

So to start, today let's just focus on the ADC side of this RME device. Remember that the RME ADI-2 Pro FS R Black Edition (again, let me just call it the "FS R BE" for short) is an evolutionary step from the ADI-2 Pro FS ("Pro FS") that I started using 2 years ago. Consider this article as building on some of what we already know about the Pro FS as an ADC from 2018 with requisite repeated tests comparing the two machines and using today's software.

Saturday, 29 August 2020

SUMMER MUSINGS: Modern Tech Life; obligatory home computer mechanic - NVMe replacement, WiFi Router. And thoughts about "high end", high priced DACs and value (Recent Darko & Sircom).


I was actually planning to just take a little break this week but given that it's almost September, I'll be away for Labour Day and school's starting for the kids with likely some virtual elements, I thought I'd just pen a not-too-long post not so much about audio but rather the highly computer-dependent world we're living in (with a bit about audiophile stuff to end).

Saturday, 22 August 2020

SUMMER MUSINGS: The Soundroom - speaker layout, vibration control & correction. (And importance for the subjective reviewer!)


I thought before summer's over, it was time to "shoot the breeze" again and talk generally about a very important topic that affects all of us audio enthusiasts with what I hope are some practical suggestions from my own "journey" here at home.

The image above of a room set-up came from an article back in 1960 entitled Room Acoustics for Stereo by Abraham B. Cohen (Electronics World, January 1960 - make sure to also check out Part 2 here from February 1960). This was a time when many homes were still transitioning from the monophonic single-channel era to the bold new world of stereophonic "3D" playback with an opportunity to virtually experience an actual soundstage in the comforts of the living room. Those must have been exciting times, perhaps comparable in my lifetime to the late '90s with the release of AC3/DTS receivers providing discrete multichannel home theater.

As you can see from the pair of articles, already back in 1960, the groundwork had been laid out for what constitutes conditions for good "stereorama" sound. Best practice tips to achieve a sense of realism, the variables related to speaker placement in a room, angles to target for from the sweet-spot, distance between speakers and orientation like toe-in. Room characteristics like absorption characteristics of materials, reverberation time, room layout were discussed as well; all this informed by decades of professional recordings and studio design that came before.

Saturday, 15 August 2020

RETRO-MEASURE: Pioneer SX-880 receiver (1978). And the amplifier "THD Wars" of the '70s?


Back in the 1970's, Pioneer among various Japanese brands like Sansui, Sony, Yamaha, and Technics brought popular, budget-conscious audio gear to the masses. With the prices of solid state components dropping, these amplifiers powered many college parties and brought music into the homes of many audiophiles of that generation.

Check out this ad from back in the day featuring the Pioneer SX-780 (45Wpc):


Nice to see that the idea of "high-fidelity" featured prominently rather than some nebulous idea of "high end" audio. Today, let's measure and discuss the sound of the last in the Pioneer SX-800 series of receivers, the Pioneer SX-880 featuring up to 60Wpc into 8Ω. The SX-880 came out in 1978 with a retail price around US$425. Thanks to a large part to central government mismanagement... err... inflation, this would be about US$1700 2020 dollars which would buy a rather advanced multichannel receiver like the Denon AVR-X4500H these days.

Saturday, 8 August 2020

DIY: Raspberry Pi "Touch" Audio Streamer (2020) and RoPieee - US$160. Spectral tilt, educational articles, and anti-audiophoolery...


It has been awhile since I built my Raspberry Pi "Touch" Streamer discussed back in 2017. We're here now in 2020 and I had the need to put another one together. Since 2017, I've been using Roon more than Logitech Media Server (LMS) in my sound room so I thought I'd focus on installing RoPieee for this article although piCorePlayer remains my preferred software for LMS use (I still have LMS running on a Linux VM on my Server machine for remote playback of music away from home).

Build price for this simple Pi USB streamer is very reasonable. Based on Amazon US$ prices at the time of writing:
Raspberry Pi 3 B+ - $42
AC Adapter 5V/3A with switch (microUSB for Pi 3) - $10
Official Raspberry 7" touchscreen - $64
SmartiPi Touch 2 case - $30
SanDisk 64GB microSD - $13 
RoPieee software - donation-ware download, your choice "standard" or "XL"
Grand total of <US$160 for this USB audio streamer with 7" touchscreen.

Saturday, 1 August 2020

PREVIEW: RME ADI-2 Pro FS R Black Edition AD/DA Converter


Look what showed up at my door (finally!) the other day. This is the latest hardware update to the RME ADI-2 Pro line of converters, the RME ADI-2 Pro FS R "Black Edition" - quite the mouthful! Let's just use "FS R BE" for the rest of this article for short in reference to the name.

Currently, the street price is around US$2,000.

Back in mid January, RME debuted this latest iteration of the ADI-2 Pro at NAMM 2020. Since 2018, I have been in contact with Matthias Carstens (co-founder of RME) off and on about the ADI-2 Pro FS that I have been using for measurements on this blog. Shortly after NAMM, I contacted Matthias about getting an upgrade as I could use two of these ADI-2 Pro devices - one for the soundroom and another for my test bench - when the company starts shipping these.

Saturday, 25 July 2020

SUMMER MUSINGS: Post Hi-Res Audio. Why hi-res is often not for the best. Resampling, dithering and de-clipping.


It has been a good summer around here thus far with time off, working around the house, and of course time to enjoy the warm weather for a bit. Here in Vancouver, the late fall to early springs are typically dark and rainy so I'm happy to catch a few photons when I can :-).

With the pandemic, this will certainly be an unusual summer/year. Unless things change substantially, this will be the first year in 2 decades that I won't be traveling off the continent for vacation or work - heck, I can't even visit the USA at this point without at least 2 weeks of self-quarantine back in Canada. In that spirit of staying put and cleaning up this year, I thought I'd talk about a few related items that have been on my mind pertaining to my music library.

A few months ago, I wrote an article about remembering that for home audio, we must always think about the big picture triad of PRODUCTION - REPRODUCTION - PERCEPTION. So often, we in audiophilia spend disproportionate amounts of time on the hardware aspects of reproduction (what's new? how do these devices measure/perform?), or speak of subjective perceptual experiences. Much of that I think is a reflection of what our magazines, online sources, and forum topics revolve around. Maybe that's what the Industry also wants us to think/talk about. We so often forget that in fact, a huge amount of what we perceive - or can perceive - has already been "baked into the cake" from when favourite recordings left the studio (or perhaps specifically the mastering engineer's workstation).

Saturday, 11 July 2020

OWNER'S COMMENTS: Pass Amp Camp Amp (ACA) 1.1 by Mitch Barnett


[What follows are comments from Mitch Barnett, the owner of the Pass Amp Camp Amp 1.1s that I listened to and measured. I appreciate Mitch's input on the matter, it's a great example of how owners of the ACA might put them to use in one's system, recognizing one's needs.]

Thanks Arch for the great time with your family for a fun night of good food, wine and of course music and movies. Great job on the objective measurements and subjective listening impressions, “It actually sounds good…” with the caveat of not asking too much from the amp. In my mind, this is the dichotomy between objective measurements versus what sounds good to our ears.

MEASUREMENTS: Pass Amp Camp Amp (ACA) 1.1. The crossroads between objectivism and subjectivism, and reconsidering von Recklinghausen.


Back in 2012, Dana Brock, Nelson Brock, and Mark Cronander (aka Variac) organized an "Amp Camp" in Northern California at the Brock's ranch. Nelson Pass, well known among audiophile circles, contributed with one of his designs and I'm sure they all must have supervised the participants as they went about soldering and building those first kits. The result was a simple, solid-state, Class A amplifier to take home. This amp was of course the Amp Camp Amp (or ACA) which we'll be talking about and measuring here.

You can see Pass' article introducing the amplifier with schematics and measurements. What a great idea! There is no substitute for the value of experience and the memories of building something, especially while sharing with a loved one; regardless of the subjective or objective performance of the final product.

The ACA has developed a healthy following over the years - check out the long-lived discussion thread on diyAudio. Nothing official, but I heard over the grapevine that there have been >2000 kits sold, suggesting conservatively >2500 actual stereo amps out there with no accurate way to estimate non-kit PCBs, unofficial "clones", or just completely DIY builds with the published schematics.

Saturday, 27 June 2020

MEASUREMENTS: Topping DX3 PRO V2 (LDAC version) - plus frequency/amplitude stepped sine measurements, a quick look at the 8kHz USB PHY packet noise, and AirPods Pro "Spatial Audio" coming...


So I got another DAC here at home - purchased through usual retail channels of course :-).

The Topping DX3 PRO (~US$220) is a device meant for those who want wired (S/PDIF TosLink, Coaxial, USB) as well as flexible Bluetooth 5.0 wireless input. There are 2 versions of the DX3 PRO out there - the earlier version reviewed/measured at Audio Science Review by Amir and the newer one which I have here with LDAC support (Sony-developed "high resolution" Bluetooth CODEC, also measured by WolfX-700) released in late 2019.

At some point, I figure it would be interesting to compare how the various Bluetooth codecs perform since this device can accept the lowest common denominator SBC, plus AAC, aptX, aptX-LL (Low Latency), aptX-HD, and LDAC audio - about as broad a range as I've seen among Bluetooth DACs (here's a good primer on these acronyms).

For today, let's examine the device's standard DAC performance and run it through my typical procedure with a few new measurement variants to see how it performs.

Saturday, 20 June 2020

MUSINGS/POLL: A lifetime of digital audio storage? Enterprise / Data Center hard drive update.


For this week's post, I thought I'd spend some time talking about music storage, a recent upgrade, and some thoughts while reviewing my own music collection. A potpourri of observations and ideas, ending with a little poll...

A few weeks back, I saw this "extreme" server system described on Audiophile Style. I certainly agree that a machine like this is very much extreme for simply audio playback or as a music media server (presumably it will not even be used for something more demanding like a higher bitrate 4K/HDR movie/video player)!

What got me thinking about my own server system was not whether one needs something like this for "good sound" - of course one does not. I thought it was very cool though that the machine is capable of such a large amount of SSD storage - up to 24TB. Basically, what they're doing is putting up to 3 ASUS Hyper M.2 X16 PCIe (~US$60-70) cards in the machine. The user can then install up to four M.2 SSDs within each card (a single 2TB WD Blue 3D can be had for about US$230 currently, 2TB WD Red for around US$280). So with each ASUS card filled up, we have up to 8TB SSD storage, and 3 of these populated ASUS card results in that 24TB potential.

Saturday, 13 June 2020

BLIND TEST RESULTS Part III: "Is high Harmonic Distortion in music audible?" Subjective Descriptions


As we've seen in Part II last week, based on the preference data, there was a pattern for the respondents to this blind test to choose the samples with lower added distortion as sounding "better". I believe this is encouraging for audiophiles who seek "high fidelity" and "accuracy" in the reproduction of music. It's a demonstration that correlates objective levels of distortion with a subjective preference.

Today, as we end off the write-up for this blind test, let's consider the subjective descriptions of what was heard by the respondents. Words describing experience and feelings can be difficult and imprecise, but by correlating how listeners expressed themselves with knowing how they ranked the samples, perhaps we can appreciate the scope of adjectives used when people listen to content with significant harmonic distortion...

Saturday, 6 June 2020

BLIND TEST RESULTS Part II: "Is high Harmonic Distortion in music audible?" Respondent Results


Having described the study and procedure last week in Part I for this most recent online blind test, let's continue by looking into the results from the 67 unique respondents. For this post, we will focus on the "objective" results based on the data. As I have done in previous tests, in a follow-up post, we'll have a look at the "subjective" descriptions of what respondents perceived.

We'll start as usual with some context into the respondents' demographics, we'll then proceed to examine the sound systems used by the respondents, and from there, look at their blind listening submission results to see if harmonic distortion correlated with preferences around perceived "better" or "worse" sound quality...

Saturday, 30 May 2020

BLIND TEST RESULTS Part I: "Is high Harmonic Distortion in music audible?" Procedures & Settings


As you perhaps know, over the years, there have been a number of blind tests conducted here on the blog - "Does high bitrate MP3 sound different from lossess FLAC?", "Does 24-bit sound different from 16-bit?", "Audible difference between linear vs. minimum phase filter?", "Do digital audio players sound different playing 16/44 music?" - for a sampling over the last while...

The question this time being posed is whether harmonic distortions are audible in music, and if so, perhaps through this test, we might be able to get a sense of the level of audibility. Remember that this is a complex question... It's not just "YES" or "NO" because it can depend on the AMOUNT of distortion in question. Furthermore, we can look at ODD vs. EVEN distortions. There are also questions around HIGH vs. LOW order amounts contributing to audibility.

Tuesday, 19 May 2020

MUSINGS/MEASUREMENTS: Netgear Nighthawk S8000 (and audiophile ethernet switches)

Netgear Nighthawk S8000 GS808ES (~US$95).
Over the years, as "Distributed Computer Audio" setups have became the main music playback mechanism for many of us, audiophile companies have released various products supposedly to enhance each component in the computer system.

Last week, we talked about an expensive audiophile server computer for example. As you know, over the years, USB cables, hub-like "regenerators", "filters" and "reclockers" have been released by companies. "Audiophile" ethernet cables likewise have been on the market for many years now.

I suppose it was just a matter of time that ethernet switches became a target for the small audiophile cottage industry with products like the SOtM sNH-10G (US$800), JCAT M12 Gold Switch (€4165) and less expensive M12 Magic (€2550), UpTone EtherREGEN (US$640), Paul Pang modified switch (€279) based on D-Link DGS-108 (US$30), AQVOX SE Switch (US$950) also based on D-Link DGS-108 I think, Crux Audio Silent Angel Bonn N8 (US$399), Fidelizer Etherstream (US$395) based on Cisco SG110D-08 (<US$50), Melco S100 (£1999), Linear Solution OCXO Audiophile Switch 2.0 (?US$500) that looks like it's based on TP-Link TL-SG108 (~US$20), expensive line of Ansuz PowerSwitches among a few other options.

Saturday, 9 May 2020

MUSINGS: Windows Server 2019 update, RSC performance issues with Aquantia 10GbE AQC107, and expensive audiophile server computers (like the Wolf Audio Alpha 3 SX)...


Hey everyone, as mentioned last time, this past week I've been updating my Server computer (Intel i7-7700K based, 32GB machine) over to Windows Server 2019 Standard. It has been a few years since updating to Server 2016 which was an upgrade from Server 2012 R2 before that and Server 2012 initially installed in 2013! I figure it was about time to back-up all the essential data and totally start fresh. Some of the hard disks are 10 years old (a couple of Western Digital Greens and Red drives) and also on my list to be replaced soon. As you've probably experienced, while Windows has improved significantly, over years of use, it can bog down with inefficiencies from old installs hanging around. While maintaining IT stuff is generally not much fun, like "spring cleaning", it's necessary...

My choice for the Server operating system is due to some work related functions (web serving) I needed for this machine - stability, speed and security are more important than application compatibility. In that regard the Windows Server family has over the years proved to be reliable. For my audio and video server needs, as a platform to run RoonServer and as a fast NAS, the speed is certainly appreciated.

Saturday, 2 May 2020

MUSINGS / MEASUREMENTS: Multiple subwoofers to reduce nulls. The USB/UFO faithful. And thanks for the blind test submissions!


A few weeks back, I ran into this interesting article - "Is the room the most important component?".

In summary, it seems like the article is basically saying that we can rearrange our gear or perhaps treat our rooms in ways that sound good, thus making the room less important than a general consensus might suggest. There seems to be an undertone of trying to downplay the role of the sound room and suggesting that one can spend more money on high quality gear and still benefit. OK, sure, to some extent that's true; but there are obviously limits. After all, if the room is way too small, cubical, highly reflective and impractical to treat, speakers inappropriately shoved deeply against walls, or if there is no space behind the seating position, there's obviously no point spending $$$$ on gear that one can barely appreciate! In my opinion, the quality and size of the room and quality of the gear (especially speakers) should be reasonably balanced.

IMO, without doubt, the room does play a major role in the sound quality; I think it would be silly to suggest otherwise even though I have heard some completely deny this over the years! For example, objectively we can easily show the nodes (nulls) and antinodes (peaks) resulting from reflections and standing waves in our small domestic listening rooms. Subjectively, these effects/limitations are easily audible as well. The way we arrange the speakers will interact with the inherent properties of our listening room in ways much more significant than much of the concerns "hardware audiophiles" often speak of or obsess over (like which CD player/DAC/streamer/server we use, cable differences, or if jitter even is audible :-).

The above should be obvious to readers already. Over the last month, with "social isolation" in place, there was time after work to try out something I've wanted to play with for awhile. Let's see if I can smooth out the low-frequency response in my room by experimenting with the use of an additional small subwoofer...

Saturday, 25 April 2020

MEASUREMENTS: Soditer "Fourth Generation" USB Type-C Headphone Adaptor (Realtek ALC4042).



These days, many recent smartphones no longer include analogue headphone jacks. Implicitly, the idea is to favor wireless Bluetooth headphones instead. As a result, if you want to hook up your wired headphones, one would need to buy a headphone adaptor which may come with your phone (for example, Apple at the beginning included their Lightning to 3.5mm Headphone Adaptor and these days may include some Lightning EarPods).

Recently, I upgraded my phone to the Huawei P30 Pro which does not have headphone output, so I was in the market to get one of these for the phone's USB Type-C digital connector.

Many of these headphone out / DACs are inexpensive, and the adaptor I have here today - the Soditer USB Type-C Headphone Adaptor - ~US$25, is advertised as supporting hi-res playback (even up to 32/384), and is claimed to provide up to 35mW into 32Ω headphones. Let's have a look...

Saturday, 18 April 2020

MEASUREMENTS: Roland Mobile UA-M10 DAC (PCM, 1-bit, 4-channel, Balanced Out)

Roland UA-M10. Note colorful level LED, 2 volume buttons, 2x3.5mm outputs; the one on the right labeled "A", and the one to the left where I have a cable connected "B".
In late 2019 when I visited my friend one afternoon, he showed me an interesting DAC he owns. It's the Roland Mobile UA-M10. This device has been on the market for awhile (since around late 2015), it's also a little more expensive than most small-form-factor, USB-powered DACs out there these days at around US$200-250.

Physically, it's a small, light, aluminum box with two volume buttons up top and a bright LED indicator that dances with the music when playing. The bottom surface has a couple of rubber strips across the length of the box that protects from scratching whatever surface you're putting it on - nice touch. Like many other USB DACs these days, it's completely powered by the micro-USB 5V input. The heart of this box is the AKM AK4414EQ DAC which interestingly is a 4-channel DAC (see datasheet). The device makes use of this by having both a headphone out phono plug on one end plus a line out phono output on the other, each of which could be playing independent content. The driver has the ability to tell the DAC which mode it should operate in.

Saturday, 11 April 2020

MEASUREMENTS: NB Cables "The Vigilante", Raymond Cables, Canare 4S11, Slinkylinks Silver Speaker Cables. (And related thoughts on audiophile "snake oil".)


Continuing on from the investigations into LCR parameters for speaker cables started a few weeks ago, today, let's have a look at a few more cables with the REED Instruments R5001 (remember there are limitations of course but comparisons can still be made across cables). As you can see in the previous article, the cables I measured were zip-cord types compared to my DIY "Colorful Speaker Cable". Today, let's look at commercial speaker cable offerings and check out some numbers for each.

Among the cables in the montage above, notice that I do have a more "exotic" cable, the silver conductor, Slinkylinks Biwire with gold banana plugs (asking price back in the early 2010 for 4m/13' was NZ$1840 = ~US$1100 today). As with last time, let's go through the measurements one by one, ending off with those Slinklinks.

Sunday, 5 April 2020

MUSINGS: COVID-19 mortality, age distribution, underlying health conditions and hope beyond...


As I publish this, it's April 5, 2020. We are in the midst of the coronavirus/SARS-COV-2/COVID-19 pandemic. The world is afraid. Borders are shut. Stores are closed. Concerns with crime increasing as a sign of social stress and perhaps distress.

We're also at a bit of a loss in terms of leadership through this. Again, speaking from a North American perspective, there is no "vision" of what the future might hold or any talk as far as I am aware of plans to relax restrictions. If anything, it's the opposite, an atmosphere of rule by fear with threats of further shutdowns. As I expressed in the second half of March, we are in a state of fear, with "abundance of caution" being as good a catchphrase as any of what's happening here; uniformly expressed among governments and public health experts.

In all this, let's look at some statistics and think about this more, shall we?

Saturday, 4 April 2020

REVIEW: Optimal Audio and Video Reproduction at Home (Vincent Verdult, 2019)


For those reading this blog, I think I've been quite consistent over the years in expressing my views about audio/visual technology. I think my philosophy around the importance of focusing on the objective and being careful with purely subjective evaluation has been clear.

As such, once awhile when I am contacted to consider a new product or asked to provide an opinion, I will of course evaluate through that perspective.

A couple months back, I was contacted by Vincent Verdult to have a look at a book he recently published by Focal Press, succinctly titled Optimal Audio and Video Reproduction at Home, released in 2019. I was sent the 346 page paperback from the publisher, it's also available in hardcover and eBook editions. Let's spend some time with the contents of this book and consider how one might find it helpful especially as an audiophile.

Saturday, 28 March 2020

MUSINGS: On art, artist appreciation, and "core music"... by 24bitbob


I received a wonderful E-mail from reader 24bitbob in Australia just before the clock turned 2020; considering how the world has changed this year, it feels like the message came ages ago!

As I've mentioned over the years, it is wonderful chatting to audiophiles from all around the world. It's great to hear and consider the insights of others. Ultimately appreciate what the audiophile hobby has meant to them (you!) as a source of joy and love of the music...

Mon 12/30/2019 4:56 AM

Hi Arch,

I’ve followed your blog for a while and made a few comments / observations along the way under the pseudonym ‘24bitbob’. Truth be told I’ve enjoyed hi-fi as a hobby since 1970-something, and I’ve learned at various times the trap of getting caught having to upgrade things. If taken too far it leads to frustration more than happiness, so I dabble in the hobby; in and out, in and out.

Monday, 23 March 2020

MUSINGS: COVID-19 - "WE CANNOT LET THE CURE BE WORSE THAN THE PROBLEM..."


Thought I'd put up a post today as a bit of a "comment cleaner" for ongoing discussions. A few days have passed, I'm not seeing much change here in Canada. Yeah, more testing done, more positive cases, but so far so good in terms of emergency departments not being overwhelmed. Preparations looking OK and containment systems not being breached. Strong health policy seems to be working within the hospital system that I can see.

Friday, 20 March 2020

MUSINGS: COVID-19 - "Abundance of Caution" | "Abundance of Fear"


As discussed a few days ago, there is remarkable fear out there with COVID-19. Last night, as I was checking out the news, I clicked on Drudge Report to see what's going on in this world and got that screen above.

Wow. What a time we live in. I suspect if we checked Drudge on September 11, 2001, the top part of the screen with numerous headlines would have all been about the same topic as well!

Wednesday, 18 March 2020

COVID-19: A few thoughts... Finding tranquility in a time of panic.


Greetings,

For the most part, I talk about rather petty stuff like sound equipment and audiophile discussions on this blog. :-) However, nothing has stopped me from posting on other topics of interest over the years! I was supposed to be on Spring Break this week but with all the flight shutdowns, I'm staying put in Vancouver which gives me time to watch the news, check in on work once awhile, and think about the state of the world.

Needless to say, things have changed markedly within weeks due to the SARS-CoV-2 virus and the COVID-19 disease pandemic that it causes. I thought I'd put up a post this week to document a few facts and figures I've come across, many of which not seemingly focused on as much in the media. As usual, I'm interested in the big picture and let's try to see the context of what's going on.

As per audiophile discussions here, let's remain science-driven and not get off track into tinfoil-hat, homeopathic, conspiratorial, la-la-land, OK?

Wednesday, 11 March 2020

MUSINGS: "Which measurements matter?" Importance of considering the complete audio chain. And a listen to room DSP filters...



Very busy these last few days so I thought let's address an interesting discussion question I've seen over the last while about measurements and audibility. Here's a forum comment from tapatrick over on Audiophile Style the other day:

think you have done a good job in your blog post of covering all the relevant areas involved from music production to listening. And maybe the conversation is now concluded. If only everyone would acknowledge and respect each others 'intent' as you put it then there would be a lot less misunderstanding. I am none the wiser which measurements matter but I have to say I'm now clear that measuring and analysing equipment outside of listening leaves me cold. I will leave that to others more qualified but I will keep an eye on developments.. :).

Sunday, 1 March 2020

MUSINGS: Audio & Music - The audiophile Big Picture view... (And "objectivists are no fun".)


It has been a very busy week at work and obviously the world this week has been going through all kinds of turmoil on account of Coronavirus and the very real effects it's having on travel, production, the economy, and of course health care!

Over the last week, I spent some time on Audiophile Style chatting with the folks there in the thread on "Why are objective assessments important...". As you can see, many topics were covered including subjectivity, objectivity, what is a "perfect" reproduction chain, whether objective results correlate with subjective experience, all the way to a discussion of neuroscience, the mind, etc...

Saturday, 22 February 2020

MEASUREMENTS: Archimago's Colorful Speaker Cables, KnuKonceptz, AmazonBasics, and "freebie" speaker cable. (And changes at Audiophile Style.)


As hinted at with the article a couple weeks back of my simple DIY speaker cables, let's spend some time considering the basic speaker cable measurements, how these affect the hi-fi system, and get a sense of the magnitude of effects to be aware of.

If you read the audiophile publications, it's not uncommon to see articles paying lip service to the importance of science in cables and measurements, yet at its core, they're often written to perpetuate fears, uncertainties, and doubts (FUD). IMO, this recent Positive Feedback article is a good example in that it acknowledges resistance, inductance, and capacitance but goes out of its way to describe complexities without actually giving you any contextual information about the values of these quantities. Notice the title. The "snake oilish" nature of something isn't nullified just because acknowledgement of the term is used. And certainly, denial is to be expected from supporters of "snake oil".

Saturday, 15 February 2020

MEASUREMENTS & LISTENING: Topping D30 DAC by Greg Dunn. (And briefly, more USB cable nonsense.)


[Ed: Every once awhile, it's a pleasure to have guest posters adding their voice to this blog! There are many folks out there doing measurements, experiments, and I've certainly been in contact with a number of audiophiles with great stories about the gear they have, music they love, and the audiophile pursuit in general!

A few weeks back, Greg got in touch with me around the Topping D30 DAC that he has. This DAC was brought up in comment discussions back in 2018. The D30 measured quite well on Audio Science Review, but has been blasted as subjectively sounding bad - "like ass" as it were - on the Super Best Audio Friends forum. Elsewhere in that SBAF comment thread, the D30 was described as having "poor soundstage and poor timbre".

With this polarization of opinion, it's great to see Greg stepping up with his own opinion based on objective testing and subjective listening... Take it away, Greg!]

Saturday, 8 February 2020

DIY: Archimago's Colorful Set of Speaker Cables. (And about that Darko/McGowan "EXPERT" interview on USB cables & other claims.)


While it's probably perilous to guess which cables "make the most difference" (just look at the different opinions here), arguably, other than very-low-voltage phono cables that can pick up interference easily, I'm guessing that speaker cables probably can make the most difference in a sound system on account of longer lengths and the fact that speakers are low impedance devices. As a result, the additional resistance, inductance, and capacitance of speaker cables may be relevant to performance.

Furthermore, in extreme cases one could run into systemic instabilities, for example years ago the Polk Cobra cable was called an "amp killer" on account of high capacitance and very low inductance. This Nelson Pass article from back in 1980 listed that cable as having 500pF/ft capacitance and discussed the need for a damping network to avoid high-frequency oscillation with high bandwidth amplifiers. Clearly sometimes the amplifier might "see" the difference a cable introduces even if anomalies are inaudible.

Saturday, 1 February 2020

MEASUREMENTS: Do power cables make a difference with audio amplifiers?


Alright guys, as you probably know, here at the Musings, I'm not in general a "cable believer". This doesn't mean I'm a "cable denier", after all, I need them in order to hear something from the system :-). Over the years I have written about silly cable claims, and here's the summary post looking at all the cable varieties I've measured (I will of course include this article in there as well).

With measurements dating back to 2013, I have neither heard nor seen any evidence to compel me to recant my opinions on this matter. Furthermore, I have not seen any new articles exploring the topic with any kind of depth in the audiophile press. No audio cable company has produced material demonstrating a believable, sonic benefits for their $$$$ products. Despite countless ads in magazines, I see a lack of accountability from the mainstream press to investigate; it's really just about maintaining the status quo and promoting sales of high-margin luxury products as far as I can tell. No magazine wants to purposely publish stuff that results in loss of advertising revenue from a whole segment of products, right?

Up to now, the power cable measurements I've published have been with low-power devices (ie. measuring DAC output quality with different power cables), but what happens with higher current demands, when the device needs >100W from the wall socket? In the last few months, since I've been working on amplifier measurements, I have had the opportunity to try measuring power amplifier output using different power cables.

Saturday, 25 January 2020

INTERNET BLIND TEST: Is high Harmonic Distortion in music audible? (plus Pet Shop Boys' newest, HRA needs HDR)


Another year, another Internet Blind Test, my friends! For me, doing this is important because it keeps us honest. It's worth reading this article in Audioholics published recently for an overview of the complexity of perception. I believe it's essential that audiophiles have an opportunity to participate in exercises of perception which I hope can enlighten ourselves and in aggregate, enlighten each other.

It's good to capture naturalistic data of audiophiles "in the wild" on top of information we may read from the "ivory tower" of Academia and profit-motive driven claims from Industry. Arguably, this is some of the most useful data. We can for example quite easily measure amazing levels of performance these days from our devices, but if we never correlate this to audibility, the data says nothing about relevance to humans, which at the end of the day is the only intent of these devices!

If you remember, last year we did the "Do digital audio players sound different?" test (the results systematically discussed starting here). This time around, in late 2019, Paul K [aka pkane] (who also wrote DeltaWave) contacted me to try out the early builds of his new software called "Distort"; aptly named software that allows us to purposely introduce anomalies into audio data. Among a number of distortions one could introduce is the one we've all heard off - harmonic distortion.

Saturday, 11 January 2020

MEASUREMENTS: Hypex nCore NC252MP Amplifier (+ Subjective opinions around objective testing, and CES2020)


Alright, you knew this was coming from the post last week with assembly details for this amp.

As discussed, this is an easily assembled single-board OEM Class D stereo amplifier rated at 150Wrms into 8Ω, 250W into 4Ω, and 180W into 2Ω. The enclosure comes from Ghent Audio. The amplifier is based on the Hypex nCore "phase shift controlled self-oscillating loop" design.

Let's run this box through my usual MOAR testbench as previously described and see what kind of data we get. In general for these tests, the signal path for measurements looks like this:
RME ADI-2 Pro FS AKM DAC (signal generator) --> XLR --> Douk/Nobsound NS-05P passive attenuator --> XLR --> Hypex NC252MP amplifier --> Test leads --> BNC unbalanced input of Linear Audio Autoranger MK II --> Balanced TRS/XLR --> RME ADI-2 Pro ADC --> USB --> Surface Pro 3 laptop
I'll also have some oscilloscope measurements where the test leads will be directed towards the oscilloscope instead of Autoranger and RME ADI-2 Pro.

Saturday, 4 January 2020

An Inexpensive Hi-Fi Class-D Stereo Amp for the 2020's: Hypex nCore NC252MP (DIY Assembly)


Happy 2020 everyone!

A few months ago, I saw this video on YouTube that got me thinking about just putting together an amplifier to start off the decade of the 2020's. That project in the video involved the use of Bang & Olufsen's ICEPower 200ASC and 200AC modules, good Class D amps which I agree should sound great and certainly a worthy project!

But I wanted something potentially even better. Let's put together an amplifier that should perform with even less distortion, somewhat higher power, and this can be done even easier because you don't even need to string two boards together! "Better" does come with a little higher cost, but not that much more.