Saturday, 11 July 2020
[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
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
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
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
|Netgear Nighthawk S8000 GS808ES (~US$95).|
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
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
|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".|
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
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
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
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...
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
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
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
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:
I 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
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
[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
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 laptopI'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
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.