Friday, 27 November 2015

MEASUREMENTS: Digital Room Correction with AudioVero's Acourate...

A few months ago, I posted on the use of the free DRC software for audio room correction. I was already very impressed with what the technology is able to accomplish and wanted to explore this even further. In this spirit, I invested in a copy of (((Acourate))) from AudioVero. As I had mentioned previously, there are a number of other software/hardware packages to accomplish a similar task. While I'm sure other packages would do a fine job, as a JRiver user, I wanted to create WAV-based FIR filters like I did previously with DRC which I could import into the convolution DSP and Acourate allows me to do just that without needing to run any other plug-in.

Acourate isn't inexpensive and does cost 286€. However, realize that we are entering rather "specialized" territory and although I suspect many audiophiles know about FIR-based room correction, it's not exactly mainstream (for example, how often do showrooms at audiophile shows utilize room correction DSP?)... Personally, given the amount of potential improvement, we could easily spend 286€ (~$310USD currently) on stuff like fancy cables and other tweaks achieving likely no actual improvement in sound quality.

Saturday, 14 November 2015

MEASUREMENTS: Apple Mac OS X ("Yosemite") Software Audio Upsampling

Well... You knew this was coming, right? After looking at Linux, then Windows, what about all the hub bub with Mac OS X? Depending on which forum one visits, there's often talk about Mac's being "better" as audiophile sources than PCs.

As readers here know by now, I think sound quality these days with a decent modern digital interface is primarily a function of the quality of one's DAC. So long as the digital source device is decent (not a high bar to cross by any means!) with bitperfect results and absent of any timeout errors, or extreme noise pollution, it's just fine. And one can verify the quality with objective measurements of course.

The question being asked today is, compared to the software upsampling in Windows and Linux, how well does the Mac OS X software upsampling measure up?

Sunday, 1 November 2015

MEASUREMENTS: Windows 10 "Audio Stack" / DirectSound Upsampling

I know, I know... Windows audio mixer sucks... (From the perspective of perfectionist audiophiles.)

But having just done some measurements with Linux and PulseAudio with some of the upsampling algorithms, I wondered just how well the default Windows 10 audio mixer performed as an upsampler...

Friday, 16 October 2015

MEASUREMENTS: A Look at Linux Audio (ALSA, PulseAudio)

What is that you ask? Well, it is the slowest computer in my house :-). It's a "vintage" HP Mini 110 from circa 2009. I decided recently to stick Linux on there just to see how well it ran... Here's the System Information:

As you see, I've got Ubuntu 14.04 LTS (updates current as of Sept 2015) loaded up on the old machine which has been sitting around unused for a few years. It's one of the early Intel Atom N270 CPU's (32-bit, single-core hyperthreading, 1.6GHz), 2GB DDR2 RAM. Slow 16GB SSD as the main drive. Whole OS loaded up on the tiny storage, no problem. Linux runs fine on the machine but it's obviously not fast, but works for light web surfing, E-mail, word processing... Now, how about for audio?

Thursday, 1 October 2015

MUSINGS: Meditations on the limitations of hearing & listening.

For today's MUSINGS, let us take a few moments to think about our sense of hearing. Though the auditory system is not as complex as the visual architecture, the extensive interconnections and association areas they intersect with of course provides us with an altogether unique experience integrating emotions and memories. The "drug of choice" for us audiophiles is in the auditory domain. The music we hear adds to the quality of life, and in so doing, satisfies at least to some extent a sense of meaning to our existence. Much of this is a mystery which perhaps in time with the development of neuroscience, secrets may be unlocked... But even if these remain impenetrable mysteries, there is of course no denying the value and truth to human subjectivity. That joy and meaning is wholly ours alone, it is our right as sentient beings to own and cherish.

As humans, we also recognize that we are limited in every conceivable dimension and sensory modality. We cannot smell as well as dogs, we cannot see as well as cats, we cannot hear as acutely as bats, our proprioceptive abilities pale in comparison to even more primitive primates swinging in the trees... Over the years, I have posted on the importance of being aware of these limitations so as to be insightful about our abilities especially when making claims about what is heard or not heard. For example, I think it's useful to try something like the Philips Golden Ear Challenge as a way to evaluate our own hearing acuity. Having an appreciation of dynamic limits also helps us appreciate the importance of sound levels and silence in the listening environment. Knowing the limits as a human being helps us to understand the importance (or unimportance!) of developments like high-resolution audio and what we should expect.

Saturday, 26 September 2015

MEASUREMENTS: Light Harmonic Geek Out V2

I know some folks have been awaiting the results for the Light Harmonic Geek Out V2. As you know, I have already provided a bit of a preview a few weeks back so no need to say much more I think. Generally my feelings about this device have not changes over the weeks... The 3D printed plastic smell has completely dissipated by now. It does sound great and I must say, going into the measurements, the impression was that this is some of the best sound I have heard from these little USB devices! Remember, this is a $235US unit I got as an "early bird" off the Indegogo promotion.

Let's see if the measurements are consistent with some of my early subjective impressions.

Wednesday, 23 September 2015

MEASUREMENTS: PonoPlayer and DSD Playback

Hey guys, just a quickie posting here for mid-week...

I was looking over the measurements over the last few months and realized I neglected to post results of the PonoPlayer doing DSD64 and DSD128 playback! So, instead of the data just sitting on my hard drive, I thought I might as well throw it out here for reference.

I don't believe I have seen anyone measure results of DSD playback with the PonoPlayer. I suspect a reason for this is that DSD was an "add-on" firmware upgrade released after the major magazines got a hold of these units for review. But then again, how often do you see measurements of DSD output quality?! I'm guessing that DSD playback was a "checklist" feature that some people wanted or it looked good for the company to support. Of course DSD is an acceptable input data format for the ESS SABRE9018K2M DAC chip (as it is with essentially all high quality DACs these days). DSD has been enabled as of firmware 1.0.5 back in February. For my tests, I'm using 1.0.6 from the May 2015 update.

Friday, 18 September 2015

MEASUREMENTS: ASUS Xonar Essence One MKI with DSD upgrade kit. (Part I: EEPROM)

Ahhhh... The ASUS Essence One! Even though looking back, compared to others I have listened to or measured, this DAC had its various imperfections, it has been my constant companion on the computer workstation. Through it, I have listened to hundreds of hours of music, edited my share of audio, evaluated pairs of headphones, and run various "experiments". Like an old friend, you get to learn (and at times even appreciate) the quirks. To this day, it remains my "workhorse" DAC. Why, you might ask?

Because it has 2 nice big volume knobs. One for speaker output, the other for the headphones... Simple as that :-).

If you look back at my measurements and review of this DAC back in 2013, you'll see that I generally liked it. With my perspective today, though I believe much can be improved (everything from channel/volume control balance [apparently fixed with later Essence One MKII edition which also incorporates the DSD feature], J-Test could look better, noise floor cleaner, etc...), it was the hyped up "symmetric upsampling" that was perhaps the most bizarre let-down. Imagine a digital filter that acted as a brick wall at 15kHz! Certainly made the DAC sound "mellow", but in a bad, inaccurate way...

Despite rumours of a fix to the firmware, nothing happened after I reported this anomaly. Until late 2014 by the looks of it. And I wasn't aware of this until this past month...

Saturday, 12 September 2015

MEASUREMENTS: Sound Room Update, Digital Room Correction (DRC) and JRiver DSP Studio...

Many years ago, back in 1992 to be precise - the year Windows 3.1 was introduced, when the typical PC was running below 33MHz, and Mortal Kombat 1 was hot in the arcades - I vaguely remember reading this article from Stereophile and filed it in my memory banks as something from science fiction for another day (I heard my first MP3 compressed song soon after and thought it was amazing given the data compression!). In it, Peter W. Mitchell reportedly "heard the future" and was clearly impressed by the technical wizardry of what a "Digital Signal Processor" could accomplish. The power of the digital room correction was described as "mind-boggling". If you haven't thought much about digital room correction, I would highly recommend reading that article in its entirety and consider whether the arguments make sense to you. I don't recall reading anything further about AudioSoft or whether Snell eventually created this cartridge-based "black box" audio correction system, but as we fast forward to 2015, we are living the legacy of what was described.

These days, DSP techniques are commonplace. As digital has long supplanted analogue as the preferred method of encoding our audio and video media with high fidelity, it has all become data that we can examine and modify as we desire depending on the situation. Compress to MP3 for times we don't need highest fidelity? No problem... Resize from 1080P to 720P for the cell phone screen/storage? By all means!

Explicit uses for improving audio quality include audiophile offerings like DEQX and Lyngdorf (including McIntosh MEN-220), some products like the Devialet amps include their "Speaker Active Matching" correction filters, and the home theater crowd have been using Audyssey and the like for years.

It is interesting these days then that DSP room correction is primarily the domain of home theater and AV receivers, rather than high-end audio. In fact, reading certain "high end" audio forums suggest a stigma against DSP techniques to improve the sound of an audio system. Among audiophiles, it's not unusual to see suggestions around listening to tubes, turntables, and vinyl LPs as providing some kind of elevated audiophile experience, but I've ironically experienced the cynicism when you bring up the idea that digital room correction is important if not essential as a very desirable way of improving the high-fidelity experience.

Saturday, 5 September 2015

MEASUREMENTS: Samsung Galaxy Note 5 Phone

As you probably know, for me, convenience and practicality are the most important elements of mobile audio. As much as I enjoy the audiophile hobby and achieving high fidelity sound, I think it's important and realistic in acknowledging that consumption of music on-the-go these days is tied in to the ubiquitous "smartphone" many of us carry around. They have become indispensable tools in so many ways that for music lovers and audiophiles to not take them seriously IMO would be denial. I think it's fascinating that audiophile magazines rarely ever mention these devices despite the fact that millions of us use them every day and gain so much enjoyment in the process!

The last phone I got was the Nexus 5 which I measured back in early 2014. As you can see, it doesn't measure too well using the standard test bench but adequate for busy environments. Not inspiring 16/44 performance and it does accept 24-bit audio but can't really perform beyond close to 16-bit dynamic range. It's also limited to standard resolution 44kHz only.

Last year, my wife got the iPhone 6 which I also examined. Up to 24/48, it performed well subjectively and with objective measures. Clearly a step above my Nexus 5 in terms of achieving >16-bit dynamic range. In terms of output impedance, Ken Rockwell measured the iPhone 6+ as 3.18-ohms and the Nexus 5 is probably around an unimpressive 10-15-ohms.

Well, after close to 2 years, here then is my phone upgrade:
Shown in Otter Box case.

Friday, 28 August 2015

MEASUREMENTS: It's Balanced PonoPlayer Time...

As promised in my previous post on the PonoPlayer, I was going to be getting some 1/8" TRS-to-XLR balanced cables to try out with the PonoPlayer. Mainly I just wanted to see for myself the optimal level of functioning for this device... Already the unbalanced output is capable of respectably low noise and very reasonable distortion numbers especially with high samplerate material for a portable device. I therefore expect the balanced output to be better. As you see in the image above, those cables arrived; inexpensive ones off eBay at about $12USD for the two from China.

Saturday, 22 August 2015

PREVIEW: A Look at the Light Harmonic Geek Out V2...

Well... I guess the good thing about not being a "professional" audio reviewer is that while on holiday, playing with my toys isn't really considered "work" :-).

Here's what the postman brought earlier this week:

From a bang-for-the-buck perspective, I suspect you can really get a lot of quality from the small "USB stick" type DACs. The reason being that manufacturing costs can be quite low with these devices. There's no need for fancy LCD screens, no need for a large enclosure (made of milled aeronautical aluminum of course!), no fancy connectors other than the USB port and some headphone jacks. The challenge of course is in making sure that noise levels are low in the analogue output given the proximity to the computer and dependence on the power rail off the USB port.

Previously I had already tested the AudioEngine D3 and AudioQuest Dragonfly 1.2 DACs... This time, enter the Light Harmonic (LH Labs) Geek Out V2...

Saturday, 15 August 2015

MEASUREMENTS: Audiophile Sound and Operating Systems. (Windows 8.1, Windows 10, Fidelizer & JPLAY again!)

If you look back at my writings and tests over the last few years, you will see a number of instances where I did measurements using different operating systems, computer hardware, different bitperfect software (for Windows, for Mac, "audiophile" JPLAY), and looked at things like computer CPU loads and jitter. Already, in the post on the AudioEngine D3 review, I demonstrated that even with disparate computer hardware and operating systems like Windows 8.1, Windows Server 2012 R2, Mac OS X "Mountain Lion", and "Mavericks", I was not able to show measurable differences in noise level, dynamic range, distortion or jitter with this DAC which operates up to 24/96.

The results are not surprising really, as a computer audiophile in 2015, it's quite likely that one would be using a high-quality USB DAC which is asynchronous, thus avoiding issues like the potential for significant jitter due to timing problems in the interface (more below). Yet, I get questions still about uncertainty as to whether different OSes make a difference and then there are programs out there like Fidelizer (check out this review, or this one) and even the well popularized Audiophile Optimizer (through reviews like this one) claiming improvements; strangely none of those reviews bothered to tell us exactly what DAC was used!

Friday, 7 August 2015

MEASUREMENTS: PonoPlayer - another man's observations & opinions...

A couple months back, I mentioned that I got myself one of these PonoPlayers. I got it lightly used locally and saved myself quite a few dollars (remember, I'm in Canada so would not be able to buy it directly unless specially shipped across the border). As you can see, I got one of the standard black models. Although the yellow one looks iconic and was what Neil Young went on Letterman with way back in 2012, black is more my style... And it looks pretty cool.

Since its availability back in January 2015, I believe most have no doubt already read a number of reviews on this device... I don't think it's so much the device itself, but the promotion of the whole Pono ecosystem by Neil Young that has ruffled so many feathers in the world of consumer electronics based on his bold claims about the audibility and necessity of "High-Resolution Audio"; claims of an audio "revolution". On one side are the technology sites who view the claims as nothing more than "snake oil", while on the other side - among the "audiophile press" - we see repeated praises of Pono "raising the bar" in its promotion of better sound quality.

Saturday, 1 August 2015

MEASUREMENTS: Room acoustic absorption panels... (GIK Acoustics Freestand)

"... of course you realize it won't sound exactly the same in your listening room, sir ..."

In the last few months, I've been doing more with REW measurements and examining the acoustics in my room, culminating in implementing digital room correction with my computer audio playback. It is because of this that I made the posts recently looking at speaker cables and the effect of speaker grill(e)s. Along the way, I also measured the effects of a couple of simple acoustic panels I have in the room to objectively examine the outcome.