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.

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?).