MEASUREMENTS: Experiments in audio component grounding - using a bus bar & HumX. And on the last The Cranberries album, on audio quality legacy...

You may remember a number of years ago, I talked about reducing interference I was experiencing with my Emotiva XSP-1 pre-amp. The issue had to do with the audio system picking up interference and noise through the pre-amp's "Home Theater Bypass" unbalanced RCA input when connected to my AV receiver. This "HT Bypass" mode is used as a conduit for the front channels and subwoofer out when the AV receiver is in use, typically when I watch movies with multichannel sound.

While this was a bit of a hassle for me, sometimes out of these hurdles and limitations, one is provided with opportunities to explore things like the 8kHz USB PHY packet noise which seeped into my system from the TEAC UD-501 DAC (not an issues these days with my Oppo UDP-205). Playing with things like the Corning Optical USB 3 extender allowed me to lower the noise level. Furthermore, I was also able to show that different USB hubs affected the severity of that 8kHz noise. Remember that much of this investigation was prompted in those days when devices like the AudioQuest USB Jitterbug and the silly single-port-hub known as the UpTone Audio USB Regen were being hyped up by certain websites and forums. To this day, I have not seen any evidence that this stuff improved things like noise level and jitter with reasonable asynchronous USB DACs.

A Look (and Listen) to some audio gear in Taiwan and Singapore...

Hey everyone, as discussed recently, I had an opportunity to visit Asia over the Spring Break. Since it is "audio show season" with AXPONA in Chicago last week and Munich High End coming up in May, perhaps it's a good time to post up some images and descriptions of what I found in Asia this time.

While it was a family vacation, I found time to do a little bit of "window shopping" myself and check out the audio gear and stores overseas.

COMPARISON: Roon DSP speed - Intel i5-6500 vs. Intel i7-7700K... (and the value of Intel Speed Shift!)

As mentioned, a little while back when I wrote about Roon, I was about to receive a "drop in" Intel i7-7700K CPU for my Server machine which runs Roon Core. I was able to find the i7-7700K used for a decent price and I didn't feel like dismantling the machine and upgrading the Z170 motherboard since the newest CPUs now need a Z3XX series board. Furthermore, for me, one of the least interesting "jobs" one has to manage as a technophile is reinstalling the operating system and software again... I try my best to avoid this mundane task :-(.

Note that if I were to rebuild my Server these days, I'd probably consider something like the very affordable Core i5-9600K with 6 cores. In fact, for most applications, this CPU will beat out the i7-7700K which I suspect would apply when using Roon for DSP as well.

MEASUREMENTS: Roon 1.6 Upsampling Digital Filter Options & A Discussion on "Signal Path" Quality...

As discussed last month, I've started using Roon as my main music player for the sound room recently. Back in the days of Roon 1.2, many users performed upsampling using HQPlayer. While HQPlayer integration is still available (go to Settings --> Setup to access the installation option), since version 1.3, Roon has incorporated its own DSP samplerate conversion which I suspect would be completely adequate for the majority of users.

I was curious about the upsampling digital filter options available in Roon. If you look at the "Sample Rate Conversion" control panel, we see the four main "Sample Rate Conversion Filter" settings:

On the left panel, notice that Roon allows you to select the different DSP options and add various filters to the "chain" (left lower panel). "Headroom Management" is always available if needed which basically means you can set the amount of attenuation you want to use to prevent clipping while doing the DSP processes. Default setting is a very reasonable -3dB.

MUSINGS: Of Jokers and Clowns... (On Soundstage and Perspective)

More info here.

As I sit here watching the early light in the tropics enjoying a cup of Java, I had a look again at John Atkinson's editorial "Clowns to the left of me, jokers to the right...". I believe this April 2019 issue is the last one where he is the Editor-in-Chief of Stereophile. The article examines a recent event which again brings up one of the age-old contentious issues we run into with the audiophile pursuit (perhaps the most contentious issue ever) - the subjective experience of listening/enjoying music and the use of objective and controlled methods to help us understand how well our audio systems function.

"Sunrise Sentosa" - March 2019, Singapore

Over the years, I've written on the unnecessary "war" between "objectivism vs. subjectivism" when I've thought it worth addressing articles written by some members of the press and at times the strange fear of scientific methodology in high-fidelity. We've talked about the basics of what subjectivity and objectivity mean, and further elaborated on it. In summary, "pure subjectivism" and "pure objectivism" are both extreme positions to take. The problem I find is that for decades in the audiophile press, subjectivism has been posited as somehow more important if not the only worthy position to take to the point where the vast majority of hardware reviews available these days including online sources have lost the objective component. In the process, most reviews have also lost the power to elucidate truth among the subtleties of sonic differences. Without objectivity, sound quality cannot be adjudicated based on the ideal principle of high fidelity.

POLL: Do you subscribe to a music streaming service? And a Wilson Sasha DAW, dCS, Audio Research listening session @ The Sound Room, Vancouver.

Alright guys, first off, I'm trying out a quick poll here since I was interested in how many of you are currently streaming music off a subscription site... No doubt we are seeing the shift towards the streaming, subscription model for music delivery and consumption.

It's interesting to see this article recently about the music industry's revenue growth in these last few years on account of streaming. Considering the decades of decline, I'm sure the music industry is interested in promoting any system that nets a profit. We will need to see however whether the rate of adoption in streaming wanes in the years ahead as warned by Forbes recently.

MEASUREMENTS: A look at the audio "ultra high-end" - ultrasonics! (And changes at Stereophile announced.)

In this blog installment, let's look at the "ultra high-end" of sound. Of course, I'm not talking about the audiophile "high-end" marketing term which is meaningless (beyond just another phrase for "expensive"). Rather, let's look at the frequency high-end, especially all the stuff our DACs can produce in the ultrasonic range!

If you've ever wondered, ultrasound devices used in medical imaging typically function at around 2MHz on the low end up to about 15MHz. However, the term "ultrasound" simply refers to wave
compression and rarefaction outside of the hearing range which by convention are those above 20kHz or so.

While the presence of ultrasonic content coming out of our DACs is not a surprise, what might be unclear or debatable is whether there is much of it and whether this then affects the "sound" of one's system. Rather than get bogged down in opinions, let's first have a look at what's in the ultrasonic frequencies coming out of DACs... Starting from facts, we can then perhaps come up with opinions.

MUSINGS: Let's talk about Roon (1.6) and DSP speed... (And an example of a poor quality "hi-res" classical recording.)

I mentioned a few weeks back in a comment that these days I've been using Roon for my music library and playback. A few years ago, I tried out Roon 1.2 and while good, it just wasn't quite compelling yet at that time for my needs. For years I've been using Logitech Media Server (LMS) given that most of my devices had been Squeezebox-based until recently. It certainly serves the purpose well to this day and in fact, I still run it on my server. I'll discuss why later...

I trust that you've already read or seen videos of Roon in operation so there's no need to cover the program's basics. In fact, I think I covered quite a bit of ground already back in early 2017 with the demonstration of Roon 1.2 on an Intel NUC and then subsequently talking about the use of Roon Bridge with the Raspberry Pi 3.

Since that time, with the newer versions, the program has, as expected, gotten better with even more features, more powerful user interface, etc... I appreciate the better support with display of track names and various settings with the older VFD Squeezeboxes. DSP has been added as of version 1.3 with support for room correction, upsampling options for PCM and conversion to DSD for DACs supporting the feature. We might look at measurements of these options in future blog posts. Of course, there's now also the ability to perform the first (and IMO only meaningful) MQA "unfold" in software as of version 1.5; not that I'm a fan of MQA of course.

For today's post, I'll highlight a few of the key benefits, discuss CPU and DSP speed, ending with a few suggestions I would love to see in future versions...

MUSINGS / MEASUREMENTS: On why 24/96 sampling of the Blind Test of 16/44.1 devices is good enough. [On idealized filtering tests and "real life" music playback.]

As promised, I want to address a comment raised about the idea that the 24/96 recording using the RME ADI-2 Pro FS ADC was somehow inadequate for the 16/44.1 samples in the "Do digital audio players sound different?" blind test; that the 24/96 captures are somehow missing significant amounts of the output from the devices.

For reference, I've included the original comment here from Miska:

"It [the samples] just barely catches the first image band between 22.05 - 44.1 kHz and a little bit of next between 44.1 kHz and 48 kHz. One of the devices is clean though. The ADC anti-alias filter fixes rest by improving the reconstruction by removing further image frequencies. Strongest image for most current DACs is around 352.8 kHz.

Of course playback system then defines how much overlay of these come back again at different frequencies from the DAC, since it is now running at different rate family than the original source.

This doesn't really replicate real device playback performance, but at least it captures some apparent differences. So it gives kind of hint or shadow of how the device actually did."

Although the blind test is ongoing, I figure it's still good to talk about this while not revealing the devices used of course.

MEASUREMENTS: A Look At HQPlayer 3.25; Filtering, Dithering and DSD Conversion.

Over the years, no doubt many computer audio users have heard or perhaps tried using HQPlayer Desktop from Signalyst for music playback. While there is a GUI for playback as well as a sophisticated network transport architecture, it's the upsampling and PCM-to-DSD features that are the program's claim to fame. There has been a good amount of talk about the sound quality of the upsampling algorithms and some swear by the sonic differences the program makes.

While admittedly I don't follow HQPlayer chatter closely, I don't recall reading about specific settings and what they do other than opinions about the sound quality. In this way, HQPlayer has been a bit of a mystery and I know some folks have had difficulty getting it running over the years. It has certainly been on my list of items to look into. In fact, back in early 2017 when I wrote about Roon 1.2, I mentioned installing HQPlayer but never got around to actually writing about it.

Well, after all these years, and now with the requisite pieces of hardware at my disposal for a more thorough evaluation (reasonably fast CPU/GPU system, ADC capable of >192kHz, DAC capable of DSD512), it's time to have a peek "under the hood" at what it does...

MUSINGS: Computer audio mythos? A comment on The Linear Solution's DS-1 Network Streamer.

Interesting... But in physical reality impossible of course! Perhaps like many audiophile opinions? [Info on art here...]

"Your desires and true beliefs have a way of playing blind man's bluff. You must corner the inner facts." 

--- David Seabury (1885-1960)

A few weeks ago, I read this "Quick Take" review of The Linear Solution DS-1 Network Streamer device published on Computer Audiophile (now Audiophile Style) by austinpop. Wow... I was impressed by how many computer audiophile "beliefs" were strung together all in one article! A good place to start and think about the "evolution" of computer audiophilia in 2019 perhaps.

MUSINGS: Why bother with 24-bit DACs? (With thoughts on dithering, digital volume control, normalization, streaming and LUFS.)

I've heard over the years some people wondering whether there really is a point to 24-bit DACs. After all, there is little if any evidence that "hi-res" 24-bit music actually sounds any better - in fact, you might recall that way back in 2014, here on the blog we ran a blind test and the results did not show significant audible benefit among respondents. More recently last year, even with Dr. AIX's "HD-Audio Challenge", very few people were able to experience benefits to "hi-res" audio (no surprise of course!).