Saturday, 8 June 2013

MEASUREMENTS: Part I: Bit-Perfect Audiophile Music Players (Windows).

Close to a month back, after publishing my TEAC UD-501 results, someone E-mailed me about the use of JPLAY with this DAC.

Although I had not tried the program yet, it begs the question, how's it possible that JPLAY could sound any different? JPLAY is described as a bit-perfect player openly discussed in the FAQ but if you look at items 5 & 6, they seem to imply that "timing is everything" and somehow, an optimized software player can make a difference. Note that already there have been tests questioning these claims (here's a nice one from Mitch over on the Computer Audiophile between JPLAY vs. JRiver). The fact is, there is so much going on the in the hardware level such as OS and USB buffering, DAC buffering, driver-interface interactions that are just beyond the "reach" of the player software that it really makes no sense IMO for any software developer to make such claims!

Since my hardware was already set-up with the Mac, I did the software measurements with that platform first (results here). This week, I turned my attention over to the Windows platform. Here then are the candidates for the test:

1. foobar2000 - Free, highly configurable, fully functional, a myriad of plug-ins including support for all major file formats, this is my daily workhorse for playback on my Windows machines. I generally use the ASIO plugin for most of my DAC's to ensure bit-perfect data transfer. The dynamic range (DR) plug-in comes in very useful to check for severity of dynamic range compression among different "pressings". ABX comparator is great for controlled evaluation of sound quality. In terms of sound "quality", foobar intends to "just work". It makes no pretensions about sounding "better" than anything else - just bit-perfect - nothing more, nothing less. For this test, I ran version 1.2.6 with ASIO plugin version 2.1.2. All settings set to default. Tested with the ASIO driver and WASAPI (event style). Furthermore, I installed the SACD Decoder plug-in for DSD playback - works great (remember to run the ASIOProxy plugin, configure the ASIO settings, and go to Tools --> SACD to make sure it's not transcoding to PCM).

2. JRiver Media Center for Windows - I previously looked at this player for Mac. This is of course the "original" version since the PC release came first and only recently ported over to OS X. I've used this program to easily play DSD64 and DSD128 to the TEAC DAC with DoP including DST decoding and have since registered the full version. I'll be testing version 18.0.177 here. Tested with ASIO, Kernel Streaming, and DSD playback.


3. iTunes x64 for Windows - Why not :-). Using version 11.0.3.42. It bears repeating - the lack of native FLAC makes iTunes essentially useless for me since I refuse to use ALAC (which doesn't compress as well by default) and there's no way I'm going to leave lossless files uncompressed as WAV or AIFF - ridiculous waste of HD space. Just like with the OS X tests, I've converted the test audio to play as AIFF files, volume at 100%, all plug-ins turned off. To handicap iTunes even further, I'm going to play these AIFF files for measurement off a comparatively slow Patriot Rage XT USB stick rather than copying them over to the SSD. To potentially make it even worse, I tested with DirectSound - manual setting of 16/44kHz and 24/96kHz (royal pain folks - you have to adjust the default Windows settings, iTunes settings, and make sure to restart iTunes each time).


4. TEAC HR Audio Player for Windows V1.0 - this is the TEAC freebie for use with their DAC's. Will also play DSD using either the TEAC's native ASIO driver or DoP. This program does not support DST compression for DSD unfortunately. Like with the OS X version, memory playback turned OFF.


5. JPLAY v5.1 trial - self-described as the "hi-end audio player for Windows" - implicit in this is the idea that somehow this program is capable of better sound quality. As I quoted earlier, the web site suggests that "timing is everything", which implies that today's multi-gigahertz multi-core computers somehow have issues dealing with relatively slow data processing involved in even 24/192 bitrates. Various audiophile sites have obliged with reviews claiming that this program makes digital audio "almost neck and neck with vinyl" (sure, vinyl sounds great with a good system, but is that the definitive standard?!). We shall see just whether any difference can be detected using this program in each of its River, Beach, Xtream, and ULTRAstream "engines". I used foobar2000 as the front end since JPLAY can be used with any program that's compatible with ASIO. I'll even try with full optimizations like hibernate mode, high priority, and low buffer sizes! Thankfully, the trial version only interrupts playback every 2 minutes which should be enough for the test "runs".



Because JPLAY brings with it so many options, I am actually going to split this topic into 2 sections - this first part is getting too unwieldy... Watch for Part II in this series focused on JPLAY.


Setup:

(Similar to previous DMAC Test and OS X Player Test.)

ASUS Taichi (*running audio player*) --> shielded USB  (Belkin Gold) --> TEAC UD-501 DAC --> shielded 6' RCA --> E-MU 0404USB --> shielded USB --> Win8 Acer laptop

The ASUS Taichi DH51 is the same machine I used in the laptop tests. CPU is the Intel i5-3317U (1.7-2.6GHz dual core, 3M cache). "Only" 4GB DDR3 RAM (good enough for audio memory play IMO). Of course, the machine will not be multitasking with other programs running during playback apart from the usual OS tasks. OS is Windows 8 x64 with all recommended updates as of June 1, 2013. Tests were done with the laptop unplugged running off batteries.

Win8 laptop is the Acer Aspire 5552 which has been my measurement "work horse". Again, nothing fancy, just 2.2GHz AMD Phenom X4 processor to grab data from the E-MU 0404USB and process the data through DiffMaker, RightMark, or jitter FFT analysis.


I. RightMark 6.2.5 (PCM 16/44, 24/96, and DSD64)

Like with the Mac tests, all the test audio was encoded with FLAC except for the iTunes test presented as uncompressed AIFF.

PCM 16/44 Summary:
As you see, the leftmost item is from the Mac test with Decibel, the rest of the recordings done with the Windows 8 platform...  Look at how close the results are despite measurements taken about 3 weeks apart. JRiver "KS" refers to Kernel Streaming.

Frequency Response:

Noise:

THD:

Stereo crosstalk:

PCM 24/96 Summary:
Again, the leftmost item is done with Decibel on the Mac. The rest are all from the Windows 8 machine.

Frequency Response:

Noise:

THD:

Stereo Crosstalk:

DSD64 via either ASIO native or DoP for the programs that support DSD:
This is done using the 24/96 test signal encoded into DSD64 using KORG AudioGate, then played back to the TEAC UD-501 DAC using DSD Over PCM (DoP) protocol or natively with ASIO and measured with RightMark. As usual, we see the effect of noise shaping in DSD up in the ultrasonic range.

Yet again, leftmost column is from the Mac using JRiver (OS X) playing DSD via DoP (on the Mac, DoP was the only supported way to play DSD). The foobar SACD/DSD plug-in worked very well for me, as did JRiver (Windows) and of course TEAC's own player software.

Frequency Response:

Noise:

THD:

Stereo Crosstalk:
DSD output looks good across the board.

Part II: Dunn J-Test Jitter (16-bits shown for brevity)

foobar ASIO:

foobar WASAPI:

JRiver ASIO:

JRiver Kernel Streaming:

iTunes (with uncompressed AIFF rather than FLAC):

TEAC HR Audio Player:

I don't see any differences in these spectra. Certainly no major sidebands creeping up. Although not shown, the 24-bit spectra look unremarkable also.

Part III: DMAC Protocol

As the reference, all comparisons were made to a recording with foobar ASIO.


Very high quality correlated null depth in all the players in the mid-80+dB range in this "machine listening" test. MP3 320kbps was used in the last column as a comparator - measuring in the mid-60dB level as usual.


Part IV: Conclusion

Ultimately I cannot say much beyond what was expressed in the OS X conclusions. With these Windows programs, the players are all capable of indistinguishable high quality audio output to my TEAC UD-501 whether 16/44 and 24/96 PCM or DSD using DoP or native ASIO. Furthermore, in the Windows world with the various driver models, I detected no significant difference between ASIO, WASAPI, or Kernel Streaming whether through FFT-based RightMark analysis, "microscopic" examination with the Dunn J-Test, or "macroscopic" listening test over >30 seconds with the DMAC.

Although DirectSound does not claim to be "bit-perfect" since it takes the integer audio --> converts to 32-bit float --> dithered back to 16/24-bit and sent to the DAC through Windows Mixer at a specific sample rate (set in your Control Panel for the sound device), it looks like it is able to do this with a single audio stream of the same sample rate without significant deterioration in the output in the 24-bit domain (remember the DMAC Test is 24-bit audio) - not exactly rocket science so this is to be expected. I believe many folks feel the quality of the Windows Mixer has improved over the years. Dithering down to the 16-bit domain would likely be very detectable in the measurements and would have messed up the 16-bit J-Test as well - this is why I always keep my Windows default output as 24-bits (note that the TEAC driver does not have a 16-bit setting for DirectSound so I can't demonstrate what 16-bit dithering looks like). Of course if you have multiple streams going through the mixer, things could deteriorate - but this is not generally relevant for home music playback. Also, if you run a DTS or AC3 file through DirectSound, it would not be surprising to hear errors in the bitstream.

Over the years I have used foobar, JRiver, and even iTunes for hours of listening...  Other than the tests here, I have never tried to perform any controlled testing. However, I have not found occasion to complain that the audio output sound "bad" comparatively. Personally, I like using ASIO since there's just less risk of messing up the settings.

The simple message remains - stay bit-perfect and stop worrying. So far the most important factors I have seen with digital gear has been getting a good DAC with good drivers and make sure there are no settings lingering around that could be messing up the sound. Not only is there no objective difference between Windows audio players so far, but this is also shown to be cross platform with the Mac. No need for flame wars between Win and Mac; they're the same.

As usual, I invite anyone to comment if they think these results and/or conclusions are erroneous based on controlled testing results.

Lets get "extreme" next time and consider JPLAY - could there be a measurable difference?

My music selection tonight: Hilary Hahn & Oslo Philharmonic's Mendelssohn & Shostakovich Violin Concertos SACD (2002 - sadly it looks like the 2.0 layer came from PCM 44kHz source!).

Remember to enjoy the music folks...

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