Saturday, 23 April 2016

SET-UP: Low Power Linux Audio Player (ODROID-C2 & Volumio 2)

As you know from a few weeks back, I got myself one of these little single-board computers (SBC) - the Hardkernel ODROID-C2 - and posted a PREVIEW on it. As described in that article, I had flashed a copy of Volumio 2 "Release Candidate" (0.861RC1) to my SDHC card and have been streaming music to my TEAC UD-501 DAC in the music room for the last while.

Originally, I was going to publish both the contents in this post as well as measurements but it quickly became obvious that this was going to be too unwieldy (plus the day job got very busy)! As such, let me talk about the basics of the setup here today along with a few changes you might want to try if you're streaming from one of these Linux-based network machines. Then later, we'll get to the measurements...

Note that although I'll obviously be specifically addressing the ODROID-C2 I have here, the software is portable and at present, the good folks at Volumio have software images for many low-power computers including: Raspberry Pi, Beaglebone Black, Cubox, ODROID-C1+, etc... Just check their site to see if your machine is supported with a ready-to-use OS/app image. I've been informed that RuneAudio will also have ODROID-C2 support ahead (maybe as early as this weekend), so keep an eye on that one as well!

Sunday, 17 April 2016

RETRO-MEASURE: 1994 Sony MDP-750 LaserDisc / CD Player [and further thoughts on the importance of objectivity]

Okay everyone... For this week, let's go old skool! Feast your eyes on this baby:

Notice the microphone input to the right - karaoke, of course...
That, friends, is the Sony MDP-750, a "vintage" LaserDisc (LD) player manufactured in February 1994 "Made in Japan" according to the label on the back. My dad bought this unit when I was still in university.

In 1994, S. Africa held interracial elections and Mandela won. The IRA declared a cease-fire in Northern Ireland. Kurt Cobain committed suicide. ER and Friends debuts on TV. Doom became a hit videogame launching many future FPS's. W3C (World Wide Web Consortium) was founded. Netscape was founded. Yahoo was launched. The Pentium was found to have some flaws in math calculations! Of course, who can forget? O.J. Simpson gets arrested for murder charges after driving around L.A. in his white Bronco. My, how time flies!

Although my family had owned a couple other CD players before this device, all the previous optical media machines have since died. This machine is built like a tank (weighing in at >21lbs) and still plays LaserDiscs like a champ! I opened it up to check on the gears and cleaned up some dust accumulated over the years.

Saturday, 9 April 2016

PREVIEW: ODROID-C2 Single-Board Computer... [And an obligatory MQA addendum.]

Over the last year, every once awhile someone will come and ask me when I was going to try out a Raspberry Pi as a streaming replacement for my Squeezebox systems... Certainly I've been looking around and while I was relaxing in Puerto Vallarta a few weeks back, I decided to leisurely check online the varieties of these low-cost single-board computers (SBCs). Here's a pretty good list of recent SBCs on the market to get a feel of what's out there in early 2016.

Without a doubt, the Raspberry Pi computers are the current reigning champions in popularity. They announced 5 million units sold back in early 2015. The recently released Raspberry Pi 3 looks excellent. Plenty of support, reasonably fast quad-core Broadcom BCM2837 64-bit ARMv8 1.2GHz, decent but not impressive 1GB RAM, OK 10/100Mbps ethernet, and convenient wireless 802.11n WiFi with Bluetooth 4.1. The list price should only be about US$35 for one of these but due to worldwide shortage, there's a bit of a markup currently (very common supply-demand issue of course).

But looking around, another little computer caught my attention - the US$40 ODROID-C2 from Hardkernel, a South Korean company. This was just released in March 2016. I was able to get it here in Canada from Diigiit Robotics but I see that they're now out of stock and like the Pi 3, prices have become elevated. Here's the block diagram for the C2:
All technical details including schematics can be found here.
As you can see, it's a reasonably powerful little unit which easily can outrace the Pi 3 computationally (some benchmarks here compared to Pi 3). Quad-core Amlogic S905 CPU with 64-bit Cortex-A53's running at 2GHz, 2GB of DDR3 RAM, Gigabit ethernet, and a video subsystem capable of HDMI 2.0 4K/60fps output and hardware decoding for H.265 (750MHz Mali-450 "pentacore" GPU). Unlike the Pi 3, this unit does not have built-in wireless communications. Micro-SD card (supports UHS-1 speed) can be used or faster e.MMC 5.0 (400MB/s interface) module for flash storage. There's also an IR receiver built-in for remote control of features like volume adjustment.

So I figured... Why not? Let's get one of these little guys with the goal being to run a simple Volumio streamer out of it (I think we'll be seeing RuneAudio on this device soon also). Here's what I got:
The ODROID-C2 with clear plastic case. Note how small this computer is - about the form factor of my Costco card :-). Around the same size for the Raspberry Pi...

Tuesday, 29 March 2016

HOWTO: Logitech Media Server + BrutefirDRC Plugin in Linux Virtual Machine (VM)

Looking back, early-January was a busy time for me! A number of work responsibilities and then I also had to deal with a computer issue - perhaps THE most annoying computer issue - hard drive failure on my server machine...

Of course important data was backed up so I didn't lose anything (I keep copies of important files in both my workstation computer in the upstairs office as well as the basement server). However, replacing hard drives remains an unfortunate and tiring affair of the modern day do-it-yourself tech user and computer audiophile. It turned out than a 2010 Western Digital 2TB WD20EARS "Caviar Green" was the cause of some file access slowdowns I was experiencing. I've since replaced the drive with a new 6TB Western Digital Red 6TB WD60EFRX. I believe these "Red" drives meant for NAS usage have reasonably good reputations for reliability.

Now the "good" thing about this otherwise unfortunate episode is that as I was tinkering with the server computer, I got to thinking more about the whole "keeping it simple" idea (I wrote about this idea late last year - of course that article was more about the whole concept of simplifying hi-res audio albums). But what about "keeping it simple" on the hardware side?

Over the past few years, I've done more with my computer in the listening room (as per my HTPC build articles - here and here). This has certainly allowed me to explore stuff like starting on the path down digital room correction (here and here), easily access my multichannel library through JRiver and HDMI to the receiver, and use my TEAC UD501 DAC for high-resolution and native DSD playback through USB. That's all of course on top of the video home theater tasks. But in fiddling with all this stuff, I found myself "missing" the simplicity of what I had done for years - just kicking back in the evenings in front of my sound system and streaming beautiful music off my good ol' Logitech Transporter machine which has been my main "go to" player for close to the last decade.

Wednesday, 23 March 2016

Greetings From Puerto Vallarta, Mexico...

Greetings from this place:
The Malecon at Puerto Vallarta...

Now, obviously, there's unlikely much in the way of audio equipment or audio discussion to engage in from here. However I wanted to show some pictures of what I have noticed in terms of hardware available at all the local electronics stores (dropped into a handful while shopping with the family, wandering the city)... A bit of a cultural experience for audio lovers I suppose.

Sunday, 13 March 2016

HOWTO: Vinyl LP Cleaning with the 3M Bondo Locking Suction Cup Dent Pullers.

Time to clean some old Beatles - RIP George Martin...
Alright guys, I figured I'll post on something a bit less "heavy" and more fun for this week :-). (That's assuming one could consider LP cleaning as potentially fun rather than neurotic or obsessive...)

Although for the most part I listen to digital, I do still enjoy rummaging through the used vinyl at the local record shops. Great way to "get physical" with the music and great to sometimes pick up some minty LP's from the old days with sentimental value or some "classics" especially when the album cover artwork is in great shape.

As I posted a couple years back, I've got a little collection of "tools" for the LP set-up. For the most part, I still use the Spin Clean as my primary wet cleaning device. It's not too expensive, does the job well most of the time, and is quick and easy.

I had been curious about the various "record cleaning machines" as well and have tried an Okki Nokki here at home as well as had some records cleaned at the local record store using their VPI HW-16.5 (I think), and another one with a Music Hall WCS-2. I actually decided not to keep the Okki Nokki because I realized I just didn't "need" it for casual LP collecting... I found the vacuum too loud (in general I find this "audiophilically dysphoric"), didn't really want to deal with the liquid reservoir nor to devote tabletop space to something I wouldn't use enough of. Admittedly, I haven't tried the ultrasonic RCM devices so maybe those can work even better although they are significantly more expensive commercially, take up a bit of space, and one would still have to deal with the water bath.

Saturday, 5 March 2016

MUSINGS: Cable Claims, Testimony ("Buyer's Guide") & Sponsored Content...

Cute CD BTW for the Simpsons lovers out there...
I must admit that I rarely pay attention to the folks at Hi-Fi+. Other than occasionally skim over an issue at the magazine stand, I find it generally lacking in details and looks too much like one big glossy advertisement.

Shortly after writing the previous article on Chromecast Audio including jitter discussions, I noticed on Dr. AIX's recent post that he linked to a 2015 "Hi-Fi+ Guide To Cables" PDF and decided to wander over for a peek (I know... Bad move, right?). I'm not going to enumerate all the disturbing comments and beliefs advocated but I would like to point the reader at the modestly interesting interviews with the various founders and representatives of the cable companies. Particularly, there was one question asked of each manufacturer - whether they would comment on the best type of digital connection to use: USB, I2S, Ethernet, or coaxial S/PDIF (why not include TosLink S/PDIF?).

Saturday, 27 February 2016

MEASUREMENTS: Google Chromecast Audio - Part II: Digital Output

Chromecast Audio with optical TosLink adaptor & cable.
Alright, here's the follow-up to the Part I evaluation of the Chromecast Audio. Time now to have a look at the digital output using the mini-TosLink adaptor and standard TosLink digital optical out. Please refer to the previous post since I will be using the same settings and also the Plex Media Server system to run the tests today.

The first thing that needs to be addressed is whether the Chromecast Audio is capable of "bitperfect" output. Now, I do not have an easy way to capture the digital output, but one thing I can do is to make sure that a DTS signal encoded as 16/44 FLAC can be streamed from Plex to my digital receiver without audible issues... Indeed, in this regard the Chromecast succeeded.

Sunday, 21 February 2016

MEASUREMENTS: Google Chromecast Audio - Part I: Analogue Output

So you've no doubt seen this device at the local electronics store like Best Buy. It's part of the second generation line of Chromecast devices, the Chromecast Audio released late 2015 (the other one being the HDMI video-enabled Chromecast itself). At a list price of US$35 (CAD$45), this is clearly the least expensive ways to stream audio off one's phone or other compatible network enabled server. Remember, this light, plastic puck-like device doesn't have much in the way of "intelligence" built-in which is why it needs to be connected to an actual streaming device that will basically "push" the audio data to it, either from a local server or link it with a cloud-based music source. Effectively, this is a basic "audio renderer".

Sunday, 14 February 2016

MEASUREMENTS / IMPRESSIONS: Meridian Explorer2 Analogue Output - 24/192 PCM vs. Decoded MQA.

Image from here.
Well folks, the new Meridian firmware has been released, allowing for MQA decoding. And thanks to a friend who has an Explorer2 with the recent update, he was able to record the analogue output of the DAC playing a standard 24/192 PCM track and the same song as a decoded MQA (24/44)! This is the obvious next step in evaluating MQA after my previous post listening to and evaluating the undecoded MQA file.

The song selected for testing/listening was from 2L (of course) - the track "Bl├ągutten" from the Hoff Ensemble's album Quiet Winter Nights (2011, MQA downloadable here). The recording ADC device is the excellent professional quality RME Fireface 802.

Of course re-digitizing degrades the signal very slightly but the Fireface is an excellent ADC so whatever slight change is likely very minimal though arguably it'll add some "blurring" to the signal if we accept Meridian's claims.