Monday, 25 July 2016

A Response RE: MQA, "blocking" of Meridian's responses, and A/B Tests...

Just a quick note (remember... I'm on summer holiday and all!). Someone passed along to me this article from Hi-Fi+. It's an interview with Bob Stuart and Morten Lindberg (2L) apparently conducted in May. I'm bringing this up because the first Q&A is about "detractors" and there's this curious response:
BS: We’ve had some detractors, but frankly where we sit, we’ve been actually rather pleased how few. We’ve come in with an inconvenient truth – digital audio hasn’t been done right – so we thought the community might attack us. And one person put up a long blog about MQA that was just inaccurate, but blocked all our replies. As we say in England, “That’s not cricket!”
Now I don't know if this is definitely in reference to this blog and specifically to posts here and here but over the last few months I have heard this claimed... That somehow Meridian tried to post a response but the message was "blocked" (presumably by me) and that presumably the message would have contained corrections and answers to the issues raised.

Saturday, 16 July 2016

MEASUREMENTS: Focusrite Forte USB Audio Interface (ADC & DAC) + Summer Musings


Product shot from here.
A few weeks back, I mentioned that I grabbed one of these Focusrite Forte USB2 audio interface units for some home recording projects I wanted to do. Beyond using it as a measurement device, my old Creative E-MU 0404USB was being used for some of these recordings and I figured it was time to upgrade to something new since a couple of the analogue pots were getting a little scratchy and I figured an all-digital device like this would allow me to more accurately adjust the volume on the microphone pre-amps (indeed it has worked out very well!).

A size comparison.

Friday, 1 July 2016

MUSINGS: Digital Interpolation Filters and Ringing (plus other Nyquist discussions and "proof" of High-Resolution Audio audibility)


A couple weeks ago, Whackamus posed this interesting comment and question which I thought would be a good topic to discuss and explore in greater detail and with some examples/samples:
"I've been reading your blog for years. Or for almost four years, at any rate. I have to thank you for doing what you do. I've likewise always wanted to ask you a question, too, but I don't know how the bleep to to contact you. In any case, since I've been fretting over it afresh, I thought I'd just post it here. If you ever do decide to get to/address it, that'd be great. If not -- hey, no sweat. :)

In any case, I read the following (tonight) on the Stereophile forums:

"I personally think that MQA has some noble goals, in terms of getting as close to the original master as possible, but I think that is far less important than the elimination of the damaging pre-ringing distortion. This has been the bane of digital playback for 30 years, and over-sampling and various filter techniques have tried to deal with it, with limited success."

I won't say that I've never heard ringing -- because I probably have -- but I will say that I've never explicitly said: "Aha! Eureka! Thar be ringing!" Because -- outside of maybe a blurring during transients? -- I have no idea what it sounds like. But my question is less about MY having heard ringing than about the AUDIBILITY of ringing -- pre, post, or otherwise. In a quality DAC (which I've got to assume most of the folks posting on Stereophile.com have access to), how audible are ringing effects? Or, rather, how COMMON are they? I kind of imagine that the Meitners, Lavrys, Levinsons, Stuarts, etc. of the audio world take great care to minimize (pre-/post-)ringing effects and to eliminate ringing in the audible realm. I likewise imagine that both such things are doable, inasmuch as most of us have been enjoying digital audio for decades now. But the Stereophile poster makes it seem as if ringing is the apodeictic bane of digital audio. What am I missing?"

Monday, 27 June 2016

The Vancouver Audio Show 2016 (June 25): Pictorial & Comments (the MQA Demo, and Show Musings)


As I mentioned a few weeks back, the folks at the Chester Group have put on the Vancouver Audio Show again this year at the Hilton Metrotown (in Burnaby). I must admit, it's not the ideal weekend for an audio show. Summer holidays starting, weather getting better, this is also the opening weekend for the Vancouver International Jazz Festival... I guess the "music lovers" can enjoy the great outdoors while "audiophiles" can hang out indoors checking out the gear :-). Last year, they had it in May which probably makes more sense.

I spent most of Saturday at the show. It was a blast meeting up with Mitch (aka Mitchco on Computer Audiophile, recent eBook on the use of DSP in the listening environment) and wandering the hallways through the various showrooms with my buddy Phil and catching up with my dad who was there as well. As I mentioned before, I think Vancouver has the luxury of a decent selection of "high end audio" stores already but it's certainly nice to be able to come to one place to check out the gear and listen to what's new.

Saturday, 18 June 2016

MEASUREMENTS: Gigabyte GA-Z170X-Gaming 7 (Creative Recon3Di) - Motherboard DAC / Audio Output

A number of months back, I rebuilt my HTPC set-up to run the new Skylake i5 processor. I thought it might be interesting to measure the motherboard audio output of the Gigabyte GA-Z170X-Gaming 7 to have a peek at what a typical modern "gaming" motherboard's audio output performs like. Here's the back panel and a picture of the MoBo:
Rear panel - note the blue TosLink cable, beside it the analogue phono plug for stereo out...
As I described in that article, the Gigabyte motherboard forms the foundation for the the new build. Technologies built into the new "consumer performance" Intel Z170 chipset includes compatibility with the new Skylake processors of course, more PCI-E lanes, up to 10 USB3.0 ports, up to 3 M.2 interfaces for SSD storage, etc. As I mentioned previously, this motherboard also has HDMI 2.0 + HDCP 2.2 capability (firmware upgrade available now and ready to go), plus there's Thunderbolt 3 out from that little USB 3.1-Type C port - very cool.

If you look at the Gigabyte literature on the website, you see that they're also hyping up the audio output somewhat. Upgradable opamp, Creative Sound Core3D quad-core processor (for 3D positional sound), high-end capacitors (Nichicon MUSE MW "Acoustic Series"). After installation, the audio device is identified as the "Sound Blaster Recon3Di" [presumably the 'i' indicates "integrated"].

How good is the analogue output from a modern computer motherboard like this?

Saturday, 11 June 2016

MISCELLANY: Vancouver Audio Show, Focusrite Forte Ahead, HEVC, Surround Audio CODECs...



Hey there guys, life and work is busy so I thought the post this week would be to cover a few miscellaneous thoughts from the last few weeks.

First, as you can see in the picture above, it's coming again this year! I guess the Vancouver Audio Show went well enough last year that we're going to see a repeat performance with the Show this year... Nice. I remember that there was no mention of the Show at the usual audiophile websites so I figure I'd let everyone know it's coming. Thankfully here in Vancouver we do have a few audiophile stores with good showrooms. Plus with the city (as well as much of the West Coast of North America) being a place where rich Asian investors like to park their cash (just look at the housing market!), it's a nice place to show off the goods... Of course, it also doesn't hurt given the relative strength of the US dollar to attract a few Americans up from nearby Seattle.

Saturday, 4 June 2016

MUSINGS / ANALYSIS: Is there any value to 176.4 and 192kHz Hi-Res audio files? A practical evaluation...



Check out this article from 1998 written by the founder of Earthworks, David E. Blackmer (1927-2002).
 
Although I believe some of the contents in the article above are debatable, in the years since 1998, high-resolution, high samplerate audio has of course become common-day reality for audiophiles. As I expressed years ago, I do like the 2xCD samplerates like 88 and 96kHz. But as a result of realizing that 176.4 and 192kHz songs were not being streamed properly with my Logitech Media Server with BrutefirDRC set-up described a few months back, I started asking myself, what is it we would be missing if these albums were downsampled to 88.2 and 96kHz?

Put another way, we could ask "Is there something musical about the highest octave in these 4x samplerate files?" This highest octave for 176.4kHz files would be audio containing 44kHz to 88kHz, and in 192kHz files from 48kHz to 96kHz.

Friday, 20 May 2016

Updated Room MEASUREMENTS & MUSINGS on Importance of Sonic "Accuracy" and the Audiophile.

Chapter I: Another Round of Room Measurements...

Recently, I acquired some more LP's, got a few more IKEA Kallax storage units for said LP's and put up some art as well. Here are front and rear shots of the sound room the other day...


With the physical changes and reviewing my post from last year regarding the use of (((acourate))) along with suggestions made by Dr. Uli Brueggemann and Mitch Barnett (aka Mitchco), I decided that it was time to re-do the room measurements and see if I can incorporate the important suggestions - 48kHz sampling rate for the measurements, sweep range of 10-24kHz, and incorporation of the subsonic filtering at 15Hz. If you're wondering, the dimensions of the room are ~20' x 15' x 8' with a slight frontal tapering as shown; not a huge room by any means and not ideal dimensions but at least it's not squarish/cubish (here's a study on room dimensions and acoustics). It's in the basement of my house, built as a family media room with extra thick walls to reduce sound leakage when the kids are asleep at night (I pretty well can run the sub at reference levels with kids asleep upstairs at night so long as I close the door to the basement). The main speakers - Paradigm Signature S8v3's - are 7.5' apart up front, and the sweet spot is approximately 9' from the speakers arranged like an isosceles triangle. I make sure there is decent amount of space between the couch and the rear LP storage (>3'). [As you can see, I have the ~15-year old rear full-range Paradigm Studio 80v3's back there.]

Saturday, 7 May 2016

MEASUREMENTS: ODROID-C2 with Volumio 2, and USB digital music streaming.

ODROID-C2 & unused "Fujifilm" 5V 1.0A wallwart ready for testing...
For those following along, you're recall back in March, I purchased a Hardkernel ODROID-C2 Linux-based credit-card sized single-board computer; the hardware described in my preview. I loaded up and customized the machine with Volumio 2 (RC1) a couple weeks back. And now as promised, I'll be showing some measurements using this machine with my TEAC UD-501 DAC. (Note that there has been a new Volumio image update since my last post. The current version is "VolumioRC1-fix-2016-05-03-odroidc2.zip" found here. Only fixed some boot issues apparently.)

Before I begin, let's discuss what we're trying to figure out objectively here... It has been claimed by some that the USB interface (which the ODROID will be streaming through to the DAC) can be "bad". Supposedly, it's electrically "noisy" (of course a noisy fan and spinning hard drives are also very bad). And, this is especially "bad" with computer audio because computers are electrically noisy devices and will end up polluting the output from your DAC. Hence, by this reckoning, a general-purpose computer isn't supposedly a good thing to have doing high-fidelity audio duties. Furthermore, it has been surmised by some that power supplies can be problematic. Specifically, an inexpensive switch-mode power supply (like the one in the picture above) can be noisy and again, will have deleterious effects on the sound quality.

It has been said that devices like the recently released Sonore microRendu among more fancy audio streamers like the Auralic Aries line of devices can "sound" better because they reportedly take into account the various sources of noise and supposedly have optimized hardware/software. True or not, the price of such "audiophile" grade devices can be rather substantial especially when it's a device without internal storage and acts as a digital conduit to feed a DAC.

Sunday, 1 May 2016

MEASUREMENTS: Music servers possibly using UDP packets? Issues for music streaming?

Original from Obaida's Blog.
Qmax last week raised an interesting question about UDP (User Datagram Protocol) and DLNA/UPnP servers, one of the basic "Transport Layer" protocols for data transmissions used for Internet communications. We are likely very familiar with TCP (Transmission Control Protocol) in our day-to-day lives. This is the transport protocol that carries data off our NAS drives, transmits the web pages we read, and ensures integrity of our E-mail data...

What we might not be as familiar with is this other UDP protocol of communication. Whereas TCP is "connection-oriented" and "unicast" sending data between a server and a client through handshaking, UDP is a "connectionless" system where data is "streamed" across the network with potentially multiple destination addresses ("multicast") but without a need for bidirectional communications to address re-transmission in the event of errors detected in the stream. UDP is typically used in broadcast streams like Internet radio, streaming video, VOIP telephony, and multiplayer video gaming because the occasional data error is acceptable and doesn't require re-transmission. Or in the situation with video games, it's all happening in real-time and it's actually preferable to drop a packet here and there than waste time re-transmitting and potentially causing a deterioration in the action. Another use for UDP is with DNS service using small packets. It's faster, and uses less data bandwidth across the worldwide network overall.