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.

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.

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...

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...

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.

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.

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.

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...

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...

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.

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.

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?