Monday, 17 April 2017

RETRO-MEASURE: 2002 Lynx L22 PCI audio card in a ~2008 Intel Q6600 Computer. (On "computers are noisy!" for audio)

As many of you probably know, Mitch "Mitchco" Barnett is a regular contributor to the Computer Audiophile website with his articles. He's also the author of the book Accurate Sound Reproduction Using DSP (now available in paperback). A great guy who has logged many hours back in the day in the audio production world!

The cool thing is that Mitch doesn't live far from where I am and last year, we met up at the Vancouver Audio Show 2016 (which by the way appears to be running again this year June 24-25, 2017). We chatted a bit before the show about various topics both in life and audio. From those discussions, one of the questions we wondered about was this whole notion about electrically "noisy" computers and just how "bad" the inside of a typical PC is for high-fidelity computer audio. After all, these days we see all kinds of products claiming the importance of "noise isolation" from USB cards to power supply upgrades.

At the Audio Show, Mitch kindly lent me an old computer audio card he had at home in storage which he was no longer using (in part because he's up to date with his computers and no longer runs a machine with PCI slots :-). Here it is:


Behold, the Lynx L22 24/192-capable PCI "digital audio interface" designed circa 2002. Back in the day, this package had an MSRP of US$749. It filters the power supply, is said to have very clean ground planes, and utilizes high quality components (here's a review from 2003). At a time when probably many of us were rockin' with Creative Soundblaster Live! type sound cards, this is something meant for home studios and maybe some DVD audio production... At 15 years now since the design of this device, we had to wonder - how does this sound card measure and sound sitting in a "noisy" old computer enclosure with components dating back to the era of conventional PCI (not PCIe) slots?

Saturday, 15 April 2017

COMPARISON: MQA "Authentication" & Sound Quality? (Mytek Brooklyn & Meridian Explorer2)


You've probably heard or read the catch phrases from MQA over the years. "Revolutionary", "TAKE ME THERE"... "To the original performance..." Or how about using phrases like "end-to-end technology"?

As I have said over the last few months, I don't like talking about MQA based on my general impression of what they're trying to do and the way they try to convey supposed "value" to the audiophile world through their advertisements and sponsored articles in the audiophile press. Nonetheless, sometimes it's just necessary to comment and more importantly to put some of the rhetoric to the test. There appears to be a remarkable schism between those who advocate and praise MQA and those who have concerns. I'm pretty sure there are many wishing that MQA would just go away instead of complicating music playback with yet another questionable variant.

Last week, when I wrote about the idea of MQA CD, I brought up the Pono experience as another example of failure in the recent history of the industry. For Pono, the failure was perhaps rather obvious for those of us who have been listening to 24-bit and >44.1kHz music for awhile, especially those of us who have ever bothered to try an A/B-test. It does not take a genius to realise that audible differences are really quite subtle (if even there in most cases of mainstream music) and that differences do not translate to "benefit". Without clear audible benefits, there really was no way that the promise of the Pono music store could ever excite the music-buying public... Certainly not in the way Neil Young portrayed it (sure, the hardware PonoPlayer is unique but with its own quirks of course).

Saturday, 8 April 2017

MEASUREMENTS: Oppo BDP-105 RCA, XLR, HDMI, and other stuff for the record (like MQA CDs?!)...

Recently, I was looking at my directory of audio measurement data and realized that I forgot to put up the measurements I had collected on the Oppo BDP-105 Blu-Ray player that I borrowed from a friend in late 2016. I believe the BDP-105 has been discontinued in anticipation of the next generation flagship. The last version of the 105 was the BDP-105D which added DarbeeVision DSP video processing. This would likely not affect the audio side which is what I explore in this article and I'll obviously leave it to the videophiles as to whether this processing is beneficial or not.

As you probably are aware, this device caused quite the stir in the audio and home theater communities back in 2013 when it was first released. For a reasonable price as a universal disk player, it was capable not only of the usual CD/DVD/(3D) Blu-Ray playback but also SACD, DVD-A, and even HDCD decoding. All with flexible digital input choices - USB, TosLink, coaxial, and HDMI. For analogue output, it has single-ended RCA (stereo and multichannel) and balanced XLR analogue (stereo only) connectors. Already in 2013, Oppo had gained a reputation as a good brand with their previous models, but I think this device really put them fully on the map for audiophiles and videophiles alike looking for a reasonably priced (~US$1200 at the time) device that neither sacrificed features nor quality.

For audiophiles, the high-resolution audio output is handled by the pair of ESS Sabre32 Reference ES9018 DAC chips inside. According to the BDP-105 Wiki for those curious: "In the BDP-105's stereo board design, the 4 pairs of DACs in the ESS9018 DAC are allocated as: 1 pair for the RCA outputs, 1 pair for the XLR outputs, and 2 pairs stacked for the headphone amplifier." The other ESS chip is used for the multichannel RCA output.


Years ago, I published some results for this player (along with a DSD followup) and showed that it is indeed a very competent high-resolution device. That was back in 2013 when I was just starting this blog. Over time, I have incorporated a few more measurement and I thought it would be fun to revisit the device. This time, with my newer ADC, have a look at the digital filter in greater detail, explore the difference between the use of RCA and balanced XLR cables, and see if digital input with the USB-B interface differs from HDMI, and the S/PDIF variants... I suspect many of us have heard the BDP-105 over the years, so this might provide a nice opportunity for objective-subjective cross-correlation.

Saturday, 1 April 2017

MUSINGS: Do we "need" those >20kHz ultrasonic frequencies for high-fidelity audio?



Recently I received this excellent question and link about ultrasonic frequencies from the Computer Audiophile site:
Hi, Archimago. Visit your blog frequently and find your posts enlightening and entertaining at times without the usual smoke and mirrors.
What caught my eye in the musings on MQA utilizing the Mytek Brooklyn DAC was the selection of a musical reference which had ultrasonic, specifically musical, content. After reading the paper by James Boyk <https://www.cco.caltech.edu/~boyk/spectra/spectra.htm>, ; I have been interested in the subject of ultrasonics and their (potential) effect on the listening experience fully recognizing that these frequencies are well above the capability of human hearing. Included would be identification of recordings that have musical ultrasonic content.

Given that formats such as PCM (24/96 or higher) and DSD (2x or higher)
[Ed: remember that even DSD64 1x can go >20kHz] have the potential to capture musical content above 20kHz, I am intrigued by the possibilities. As with all HiRes formats, I understand that not only all components of the recording chain but also the reproduction chain must have frequency response greater than 20kHz to accomplish this. I do see where speakers are being offered which are spec'd to 40kHz and as high as 100kHz. There are also numerous add-on "supertweeters" being offered which have this capability as well.

IF the topic were of interest to you and worthy of your time and consideration, I for one would be most interested in your musings on the subject.


My apologies for using this Musing as a portal for my inquiry but did not know how else to contact you with the proposal.

FWIW, given the potential of the existing HiRes formats to capture the musical experience if fully realized, I too am less than interested in MQA as the latest flavor-of-the-day.

Frank Zawacki
Connecticut Audio Society

Thank you Frank for the link, interesting discussion and question. I try to do what I can to collect information and synthesize posts to provide hopefully reasonable thoughts on these matters; mixed with some measurements and personal subjective impressions as appropriate.

Saturday, 25 March 2017

HOWTO: Building and Installing the Raspberry Pi 3 "Touch" Audio Streamer.

Raspberry Pi 3 + 7" Touchscreen (left) and Squeezebox Touch (right): for the Pi device, I still had the plastic screen protector on in the picture, hence the bottom left tab...
I showed you guys this picture last time of the Raspberry Pi 3-based Streamer device with official 7" touchscreen and HiFiBerry DAC+ Pro. As you can see from the image, it's very much capable of being a "clone" of the Squeezebox Touch. Furthermore, it's highly affordable with even more hi-res audio potential such as the capability to stream bitrates beyond 96kHz (remember, the stock Touch goes up to 96kHz, enhanced to 192kHz with Triode's EDO plugin).

In this post, let's have a closer look at the device and some instructions / suggestions to build one.

Tuesday, 14 March 2017

MUSINGS: Computer Audio Part II: The Basics & Suggestions



For many readers, I'm sure what I'm about to write here is relatively "old hat" by now... However, in the spirit of "Computer Audio Demystified" last week, let's talk about this powerful way of storing, categorizing, and playing our music by exploring some aspects of the foundation of computer audio in a way I hope newcomers will find reasonably accessible. I do make some assumptions in the writing that the reader has some basic knowledge of computer usage and networking. Let's consider the "architecture" of what someone might want to build, and a few reasonable options if we were to start from scratch with full disclosure of the price to build such systems.

I can imagine that some folks might need to overcome their phobia around computers. If you're motivated, just put in some time, a little patience and don't be afraid to "play" with it. More likely than not, once one has tasted the convenience and have found one's "groove", going back to only spinning physical media will likely feel archaic after a short while :-).

First, permit me to remind everyone about the two most important determinants of sound quality in a high fidelity audio system:
1. Put thought and money into good speakers, good pre-amp/amp(s), good DAC and a good sounding room.
2. Make sure the system is acoustically quiet; ideally silent.
Point 1 is obvious. The primary factors in sound quality (ie. "fidelity" achievable) are the room, speakers, and amps in that order - these are the prime candidates for sound distortion, not your computer or DAC (and certainly not stuff like cables). And Point 2 is an obvious corollary for any equipment we put in the room since we don't want the system itself to act detrimentally - this includes noisy computers, buzzy amp transformers, ground loops through the pre-amp, etc. Remember that the purpose of computer audio is simply about storing the audio library data reliably, making available a conveniently handy user interface, and the bits are being delivered in an accurate fashion to the DAC; whether internal to the computer audio device or say an external USB DAC. There is no mystery in how to come up with a solution to achieve these goals.

Saturday, 4 March 2017

MUSINGS: Computer Audio Part I: Demystifying "Computer Audio Demystified"


It's nice to see that some of the seminars at the Rocky Mountain Audio Fest (RMAF) 2016 have been posted on YouTube. It gives all of us who may have wanted to visit a chance to review the "latest and greatest" tips and updates...

Although the RMAF is hosted by the Colorado Audio Society, remember that much of the material comes from Industry; with of course the potential for vested interests influencing the content. I think many visitors to this blog would be interested in computer audio, so let's spend some time looking at the information disseminated... For your consideration, let us explore the one presented by Steve Silberman of AudioQuest - "Computer Audio Demystified" (RMAF 2016):



Feel free to watch the full 1.5 hours. For today's segment, we'll look at a bit of reality testing vs. myth vs. mysticism. You'll notice that the comments section for this video on YouTube has been turned off. Interesting. How else to discuss the contents then than in a blog post like this, right? :-)

Saturday, 25 February 2017

MEASUREMENTS: A look & listen to Roon Bridge - Raspberry Pi 3 Streaming (HiFiBerry DAC+ Pro & USB DAC)



Last time, I talked about Roon and discussed my experience with it using the NUC as the primary installation and playback. No doubt, you are aware that many people will use inexpensive devices like the Raspberry Pi 3 to handle playback distributed around one's home... And no doubt you've also come across much hyping about more expensive, low power devices when for around $100 and a little know-how, you can get it done quickly, easily and sounding great.

First, I just wanted to practically lay out a simple way to install Roon Bridge on the Pi 3 that worked for me and using which I will run a few tests to demonstrate the sonic output. Remember that the network protocol from the Roon "Core" (my Windows computer) to the Roon "Bridge" (Pi 3) is what's called RAAT (Roon Advanced Audio Transport). It's a protocol with a number of benefits as highlighted in the link.

Saturday, 18 February 2017

MEASUREMENTS: Roon 1.2 (with Intel NUC 6i5SYH)



NOTE: I know that just a couple weeks ago, version 1.3 of Roon has been released and I'll perhaps look into that a bit later once some of the initial bugs are stamped out and the system matures a little. Clearly 1.3 has a few new interesting features but the basic bit-perfect playback function I trust would be the same which is what I'm aiming at exploring in this article.

Over the last few years, I have already gradually made my way across the different audio ecosystems that most audiophiles find themselves interested in. Starting with the venerable Squeezebox / Logitech Music Server system (eg. Touch, Transporter), to standard Windows PC and Mac OS X playback, to questionable software (like JPLAY and the JPLAY update), to even just as questionable OS tweaks (eg. Fidelizer), to more recently looking at DLNA streaming using low power devices like the Raspberry Pi 3 and ODROID-C2.

For today and the next few weeks (let's see how this goes), let's spend some time on Roon, another computer audio system much lauded in the audiophile press and see if we can make a few measurements and comment on some observations and thoughts...

Saturday, 11 February 2017

MUSINGS: Discussion on the MQA filter (and filters in general)... [Update: Including a look at the classic "Apodizing" filter.]



Here's an interesting comment from the post last week...

Excellent article but I have one query. On Sound on Sound they say "MQA claim that the total impulse-response duration is reduced to about 50µs (from around 500µs for a standard 24/192 system), and that the leading-edge uncertainty of transients comes down to just 4µs (from roughly 250µs in a 24/192 system)." In that case wouldn't you need an ADC with higher resolution than the RME Fireface 802 in order to see any real differences between the Reference and Hardware MQA decode?
As I said... Dammit CBee! Now you've made me post another blog entry on MQA :-).

Saturday, 4 February 2017

COMPARISON: Hardware-Decoded MQA (using Mytek Brooklyn DAC)

As promised in my last blog post about software MQA decoding, I have been wanting to have a peek and listen to hardware decoding. Due to the proprietary nature of the MQA firmware as well as the fact that we don't have access to MQA encoder software, there is only so much we can do to explore the effect on an audio signal. Ideally, encoding a test signal and then decoding would be the best way to explore the effects and limits of how this all works...

I don't have an MQA-capable DAC myself (and honestly owning one is not high on my list of priorities), but a friend does happen to have the Mytek Brooklyn which is fully MQA-native and has the ability to decode all the way to 24/384. Furthermore, he has the use of a professional ADC of fantastic quality - the RME Fireface to make some recordings of the output from the DAC.

Image from Mytek. Obviously very capable DAC!
With the combination of the excellent DAC and ADC, we should be able to examine the output and make some comparisons. The main questions being:

1. Can we show that hardware-decoded MQA is closer to an original signal beyond the 88/96kHz decoding already done in software?

2. Can we compare the hardware decoder with the output from the software decoder? How much difference is there between the two?

Saturday, 28 January 2017

QUICKIE POST: Yes, cables matter... (for HDMI 2.0/4K/60fps/HDR...)


Well, of course cables matter! Without them there would be no sound or image! The key of course is to be wise enough to have a concept of what is needed, and how much difference the cables/wires can make.

Just a reminder, if you have not seen it yet, here is my summary of tests and thoughts on audio cables over the years if you're wondering about that.

As for today, given that time is limited this week, I just wanted to put up a "quickie" post mainly about some 4K HDMI cables I tried over the last couple months in setting up my 4K TV (a Vizio P75-C1).