I like little girls and became a potatirian as of today

Measurements and Opinions: Differences in Transport Jitter.

Measurements and Opinion: Balanced vs Unbalanced in consumer audio applications

Sometimes I wonder why we are stuck in the RCA/single ended era. I feel all amps should have transformer coupled inputs or something if we still want to have single ended output at the transducer. Its just better! No need to deal with the lack of noise rejection in wiring. Whoever said," Oh single ended is okay in short run high end applications." was either stupid or stupid.

Here we have a shielded RCA cable that I got from the local AV store, I purposely ran the cable across a DAC with R-core transformers and loopback for the results. This may be induced but the situation is true for many an audiophool running unbalanced lines with equipment racks, the induced EMI can be a nightmare. Perhaps there is a case for audiophool ultra-shielded RCA after all? The cable's length is 2m.

 Blue is for induced noise with a DAC's transformer, Red is for the same wire adjusted to induct the least noise.

 For the same loopback though with a balanced line running pass the transformer, we can see the benefits for balanced drive which is, no spurious tones.

XLR wire run pass a R-core transformer in a DAC's case, as you see, no induced noise as all of it is rejected

ODAC Measurements

These measurements were made with an EMU0404, The tests are indicative of the ODAC's performance on a good day. The ODAC as suspected test really well, these are single channel test with the right channel of the ODAC testing worse than the left(0.003% vs 0.00068%) As expected the performance is resonable however due to the nature of Sabre based devices, we get noise floor with plenty of spuriae.

Fig 1.

Low level resolution of a 1khz tone @-90.31dbFS, as expected, not free of spuriae. 

Fig 2.

Fig 3 shows the Dunn Jitter Test of the ODAC on a good day/time where the ODAC sounds clean and reasonably transparent. In the worst case scenario, this jitter sidebands. rises to -115dbFS with a lot more sidebands. While arguably inaudible, to me the changes were so significant you practically have to be deaf not to hear it. A usb reset by plugging in and out does the trick but a device like the Wyrd helps the clock maintain good lock on the data stream.

Fig 3.

Adding a usb decrapfier or linear power supply helps with increasing the ODAC's performance as shown in Fig 3a.

Last of all, a test showing the reconstruction filter of the ODAC. This test is made by playing a full scale 19.1khz tone and white noise in 44.1khz sample rate to test the ODAC's reconstruction/anti-aliasing filter. This is then captured by the EMU0404's ADC at 192khz to observe the ultrasonic behavior of the device under test. An aliasing product at 25khz will be observed due to the mathematical implications of using a 19.1khz tone which nears the 22.05khz border of the bandwidth of the sampling frequency at 44.1khz. 

44.1khz-19.1khz=25khz

The odac seems to use quite a strong linear phase filter going by the sharp rolloff of 44.1khz white noise. Suppression of the aliasing product at 25khz is very strong at ~ -118dbFS However, the ultrasonic harmonics of the 19.1khz go on outside the audio band and at pretty significant levels.

Fig 4.

 Subjectively, I thought the ODAC is an okay DAC at most given its current price point. There are more consistent sounding DACs from the same price point to be had like the UD120 from Stoner Acoustics. The Geek products would be a better choice for a Sabre sound these days given what trusted ears say about them. A problem I think is that the Sabre tonality gets to me over a long period of time and while I like the clean transients, I found it too tonally lean and fatiguing over time which is probably cause by the measured spuraie. The EMU0404 I have tops out as the better sounding interface.

Schiit Wyrd, does it work?

This is meant to complement the Wyrd thread on Changstar. http://www.changstar.com/index.php/topic,1652.0.html. In my test with the Objective DAC and a few Tenor 7022 usb chip based DACs, I can acertain with measurements and subjective hearing that the Wyrd does work.

With the ODAC on a good day(there are bad days with the ODAC) the Wyrd brings to the table a better sense of speed and delineated transients meaning that a note's decay is shorter and the attack comes in quicker subjectively. 

In measurements, the biggest differences can be seen in jitter test. With an Audio GD with a Tenor 7022 isochronous Adaptive interface, the harmonics of the signal changes a lot with the Wyrd in the chain. I credit this mostly due to the change in jitter performance by adding the Wyrd into the test chain. Some sidebands disappear however there are some new spuraia, but overall the change is positive.

Somebody has asked me whether the Wyrd would work with Asychronous devices, the answer is a firm yes. Reduction in spurious artifacts.

Computer Listening

A bunch of people were a meet recently and some have sat down and were(hopefully) impressed by the nice music coming out of my computer's X-fi HD DAC and Objective 2 amp. Computer audio has been in the explored if I would say, extensively in the past decade or so. In the past years, many websites are dedicated to music streaming and downloads like Spotify, HDtracks and E Onkyo Music. For those looking for a quick guide on listening to music in a more optimum way, hopefully, this is the guide for you.

Throughout my short journey in the audio landscape, I have discovered a few great music software which does great at what is a deceiving simple task, playing music right. In selecting a player, I look for a couple of things, bit perfect output and effects plugin support. Having bit perfect output ensures that Windows or Mac OS does not do anything that may add distortion in the signal and allows us to be able to add our own desired effects from the plugins. Plugins will be explained below. To me, my player will preferably support Virtual Studio Technology(VST) plugins as there are many available and if you are a pro audio guy, that one set of plugins can be used for many DAWs as well.

To introduce to new users, iTunes, although a rather basic player, has support of bit perfect output on Macs via Audio Midi and on Windows, via Quicktime, one can achieve bit perfect output on your PC. One of the greatest audio player is the opensource foobar, which I personally use for track comparison purposes, it is easy to use and there are plenty of plugins(or "components") to enhance your experience. For my own listening pleasure, I make use of Jriver Media Centre, a paid player along with a set of VST plugins to enhance my experience. Take note that in Windows 7 onwards, WASAPI is my preferred method of getting a bit perfect output. Mac users have alternatives as well, listed here.Now on to the plugins I use. 

Plugins and audio:

Plugins or DSP(digital signal processors) like foobar and VST ones are to me, essential to the computer listening experience, and I always, always recommend getting player that can support . VST's and plugins can add a ton of features to a already great player and really enhancing your audio experience. Some people I know dislike using such equalisers due to reasons like the music would be less "pure" and it would ruin the artist intentions, However, to me at least, this is not so and in my opinion, DSP plugins can get you CLOSER to what the artist/recording engineer hears or wants you to hear, provided you use it correctly. I will be introducing 2 essential types of plugins for basic listening, whether on speakers or headphones.

For speakers and headphones, equalisers are the bread and butter of the audio experience to me. Many say they are a "dirty" way due to the way they distort signal but I beg to differ, to me, they are a way to compensate for your audio gear's weakness and sometimes, emphasize their strengths. To equalise, one should aim for their system to be as neutral sounding as possible and equalise to neutral before adding the desired response you want, there are many ways to go about this but the simplest would be to equalise till all tones sound the same volume. I will be introducing a couple of plugins for both VST and foobar.

The next type would be crossfeed, crossfeed to me is not essential but a real big bonus to have in headphone listening and in many times, can help improve perceived soundstage and imaging of even a headphone that has already great imaging. Crossfeed mixes the right and left channels slightly to give a centre channel that gives the illusion of having speakers. Images of the sound in or behind the head are put in front which makes the music sound more natural on heaphones. 

For 

VST plugins

Basically anything from RS-MET, the site has great great plugins whether you are a basic or professional user. One particular VST anyone, including myself, is the EasyQ plugin, simple and effective, it gets equalisation correct.

Another VST specially tailored for headphone listening which I now feel is unrivalled by almost any plugin in terms of features and effectiveness is the Tonebooster Isone plugin, which while not free, is totally worth your money(bought mine too). The Isone features Head Related Transfer Function(HRTF) which you may see in products like Dolby Headphones(in Astro mixamps) or EAX to emulate the speaker sound and I seriously swear by it. 

Foobar plugins

For Foobar users, my preferred method of getting a bitperfect output is by using WASAPI.

Xnor's 30 band graphic equaliser is a very good 30 band equaliser for those who do not know how to deal with parametric equalisers. Features a eq with no pre-echo due to its minimum phase filters and to me, does the job great.

Xnor's Xfeed is a essential foobar componenet for headphone listening, does not really compare to Isone, but heck, its free and awesome as well.

SoX resampler is a great resampler to have whether you have high res files or not, some audio devices only perform correctly or their best at higher sampling rates than 44.1khz, it is also a very fast and most importantly, most transparent resampler out there.

A little note for those on foobar, VST wrappers or vst to foobar plugins are available for those that miss VSTs just search around ;)

 Of course with all this, it won't hurt to have a good soundcard to pair with the headphone+amp/speakers, it does not have to expensive of course. Just some picks (never heard but they had some good reviews)

UD100 DAC A small nano DAC with a good chip, needs a amp though.

The venerable ODAC Base on his Objective 2 amp which I own, I will say that this is a serious DAC, not expensive but great, can be built into the O2 underneath the board or replacing its batteries.

ESI Juli@ A great PCI card featuring 2 sets of audio clocks for low jitter

Essence STX Solid PCI card as well, great lab measurements, I actually heard this one, sounds awesome.

Xonar DG A decent soundcard for those on a budget.

May Life Rant

So, with the new semester in my final year of education, life has gotten very busy lately. Not to mention the numerous number of family birthdays I seem to celebrate over the last few weeks. While I seem to be coping fine with the demands of Aeronautical Engineering, there are indeed a couple of really, really crappy subjects I can barely cope with. One is Aerospace Materials, which on top of being as boring as History class, seems to be heck hard to understand and with very little(or crappy) learning material, it is gonna be very bad news for me. Another would be the Flight Dynamics subject, which is essentially about vibrations and other physics which translates to me as you guess, pure Greek.

Now on to musics, for this season I seem to have very few albums that I really want, save for Kotoko's new single and Kalafina's "To the beginning" (getting it much later though). For me those are probably the most catchy tunes for the season.

"to the beginning" CD cover, Kalafina looking as cool as usual.

Kotoko's "Unfinished" Accel World's ending song

As for anime I enjoyed most lately, I find myself looking forward to each episode of Jormungand lately, is it because such anime are so uncommon? The last one of the type I remembered enjoying was probably Black Lagoon. Jormungand itself really appeals to me with its guns, animation and cast without using any moe factor. If you hadn't watch it yet for whatever reason, I totally recommend this. 

Also, not too long ago, I managed to get more impressions on different headphones from different places,

Stereo ION-Orchard:

First time been there and I found the look of the store a much more welcoming one then the one over at Plaza Singapura. Good customer service makes this experience really wonderful. My friend and I initially wanted to try out the new Sennheiser Amperiors but for some reason the samples have been sent back to Sennheiser, theories anyone?

Denons D2000- wonderful, neutral, they get close to the tonality of my Eq to flat R2000T monitors at home. Bonus is that they are ridiculously easy to drive. Soundstage was incredible as expected to the semi-closed design of these wonderful headphones. They don't have that edgy treble like the Beyer DT880 250ohm but thats just my initial thoughts.

HD600- Wow, a truly neutral headphone indeed, very detailed. Not worth the MSRP when you see the MSRP of the likes of Beyerdynamic's DT880 and AKG's Q/K70X. Its nice to note that my Objective 2 with its low cost had perfectly no problems driving these though.

Sony store:

Went there to take a look at some of Sony's nice goods like cams and other stuff, I do wish they sell more of their AV products in store though. Here the staff left me alone(or everyone else for the matter), which gives me plenty of space for window shopping.

Sony XBA-4

Damn was I in for a disappointment, midrange performance was downright weird, it felt um, cartoony/grainy? It was fairly disappointing for a 4 driver BA, want a 4 driver BA done right? Westone has great examples.

Sony XBA-3 

Ah, here is where the party is at, still a little of that mids problem but it was done a lot better here, I suspect phasing? The IEM overall was detailed but I'm really unsure whether it can best my TF10s(still waiting for my upgrade cable from FiiO). Has nice treble and good sound imaging but again the mids suffer a bit.

Sony XBA-1

Skipped the XBA-2 impressions because I did not have much time with the XBA-2 but i thought the XBA-1s were pretty worth the asking price, fairly detailed with good sound image. As expected of a single Balanced Armature driver, bass performance is pretty much non-existent on these.

Looks like a pretty great headphone concept, from a initial impressions by someone online, they at least managed to make it sound better then Beats. Stylish and totally classy cool, I want.

I will round this off with pictures of last month's loot.

I'm a whole season late but Zettou Amano Habakiri is really a extremely addictive song. As a huge fan of Love Live! I really enjoyed this single like the rest, Mermaid Fiesta vol.2 was a joy to listen. The art book by Fujima-sensei was worth every bit of money I spent on, been trying to resist for quite a while before I bought it but the HNNNG factor was too great. Finally, I found a partner for Haruka on my pencil case....