MEASUREMENTS: Computer USB port noise, USB hubs and the 8kHz PHY Microframe Packet Noise

Block diagram of the USB 'PHYsical' chipset. UTMI stands for USB 2.0 Transceiver Macrocell Interface, a standard bus interface for the USB chipsets out there...

One could see the "glass half full" when we run into imperfections in the audio system. For example, it was serendipitous that the Emotiva XSP-1 pre-amp had such a noise-sensitive unbalanced "HT Bypass" input that I was able to detect noise and measure it previously. If it were not for this issue, I probably would never have thought about using the Corning USB 3 optical cable or consider how to isolate the noise originating from the computer USB connection to the DAC simply because in my system using balanced interconnects throughout, I had never had a problem (subjectively audible or objectively verifiable).

Greetings from Toronto...

I've been busy over the last week in Toronto - work plus a little sightseeing and visiting with family and friends. With my hotel nearby, I managed to scoot over to Bay Bloor Radio at the intersection of Bay and Charles streets downtown to have a listen.

Vancouver Audio Show 2015: Pictorial & Comments...

Remember folks! Get me your "Digital Filters Test" results :-). Thanks to everyone who has already responded with the survey submission so far... Great work. Final results could be very interesting; keep the submissions coming.

Over the years I have traveled to other parts of the world and have enjoyed visiting "tech malls" as I just love technology, science, and advancement. There are huge complexes of geek-toys in Beijing (check out Zhongguancun), or of course Tokyo's Akihabara. You will find the occasional audiophile hangout at these places but admittedly rare... Not surprising I guess given how small a market for what really are luxury niche "audiophile" products (at least the "high-end" specialty shops). A few years ago I showed some pictures of Singapore's Adelphi Mall and I must say that this place still stands out as something special for the audiophile (not to mention places like SunTec and Sim Lim Square not far away in Singapore).

Now as you know, I'm primarily an objectivist when it comes to hardware so I guess it might surprise some that I also will check out the audiophile haunts over the years (like here and here) without getting too disgusted by the usual myths and pseudoscience promulgated. For me, it is a hobby that's fun and merges my love of music (the "spirituality" of the experience and where the subjective enjoyment resides), and the desire to understand how the world and technology truly works (where the objective side lives). The two IMO must exist in harmony, each finding balance in fulfilling the emotional side of being, yet not lost in the realities of this world and what just is.

MEASUREMENTS: Corning USB 3 Optical Cable, Ground Loops, and Noise.

Folks, remember, the "Linear Phase vs. Minimum Phase Digital Filter Test" is still running as I post this! Please give it a try and report back in the survey. I want data and hopefully an opportunity to report back on what the readership perceives (or not perceive).

I. Introduction

Indeed, "noise" can be an issue with audio systems. There's little worse that can happen to an audiophile after spending hundreds or even thousands of dollars on new equipment, plugging everything in as per "best practice", getting ready to play your first piece of music, and finding that for some reason, noise has seeped through to disturb the expectation of pristine, clean background silence from which music can blossom...

Before proceeding further, remember that noise can sometimes be subtle, and very importantly, ambient noise must be low in your sound room. It's quite possible that slight hum and low-level noise may not be significant from a normal listening distance if the ambient noise level is high (something we urban dwellers especially do have to consider!).

INTERNET BLIND TEST: Linear vs. Minimum Phase Upsampling Filters

I. Introduction

Ladies and gentlemen, audiophiles of all ages; you have probably seen pictures like the ones above many times in the magazines, posted online, etc. You know that many DACs these days feature the ability to adjust the way the antialiasing reconstruction filters are "tuned". I remember reading about and becoming fascinated by the different filters back in 2006 with Keith Howard's article on Stereophile. But it wasn't until around 2009 that I noticed Meridian started using minimum phase settings in their equipment like the 808.2 Signature Reference CD player. (I don't know if many other consumer audio devices used a form of the minimum phase filter before 2009; perhaps not as well advertised as Meridian?)

PERSPECTIVE: Poll - Upgraded USB and Sound?

I enjoy visiting the Steve Hoffman Forums for perspective. I think it's probably one of the most balanced places to hang out at. Of course, as in any audio forum, there will be a number of heated arguments here and there, but overall, it's great to see a place where heterogeneous music lovers of various experience levels and beliefs can congregate, share tips, and get advice... It's certainly one of the more vibrant audio communities out there!

Recently there was an interesting poll on whether USB cable upgrades can improve a system's sound quality. Titled "The Great USB cable debate poll" (full disclosure, I took part and posted a comment as well), it ran from February 22 to March 8th before it was closed. In total, it received 415 votes, gathered 36 pages of responses and the outcome was:

About 1/4 felt that upgraded USB cables make a difference, and 3/4 did not. Surprised?

ANALYSIS: DSD-to-PCM 2015 - foobar SACD Plug-In, AuI ConverteR, noise & impulse response...

Noise characteristics of PCM vs. DSD - image found here.

In my post last week looking at the various DSD-to-PCM converters, Solderdude Frans made a good suggestion... Let's have a look at the newer SACD plugin which has superseded the DSDIFF plug-in as the converter of choice these days for foobar. Also, it was suggested by Yuri Korzunov, the author of AuI ConverteR 48x44 to have a look at his converter package as well.

ANALYSIS: DSD-to-PCM Conversion 2015 - Windows & Mac OS X

Impulse Response: One of the talking points from back in the day as a selling point for DSD... Yup! DSD can better reproduce a 0.000003 second "click". Source: Merging Technologies

I. Preamble

It is amazing how quickly another year has passed. About this time last year, I posted the first comparison of DSD Encoders and Decoders "shoot-out" of sorts comparing Weiss Saracon 01.61-27, KORG AudioGate 2.3.3 and JRiver 19.0.117 in terms of quality - both encoding and decoding fidelity using the RightMark Audio Analyzer software. The idea was to determine which of the three created DSD files from an original 24/96 PCM test signal and then decoded it back to 24/96 in a way where there was as little change in terms of distortion, flat frequency response, and lowest amount of added noise.

Perhaps not surprisingly, the expensive Weiss Saracon software sets the standard as the most consistent DSD encoder that resulted in the best output once decoded. The differences in decoding capability appeared to be very minor (questionable audibility between the 3) but objectively, both Saracon and JRiver 19 were on par and the free AudioGate 2 somewhat "noisier" in terms of the PCM output (I speculated this was due to stronger dithering algorithm).

Well, another year has passed in terms of software upgrades to DSD decoding and I was interested to compare the decoding capabilities as of late. We have brand new versions of JRiver and AudioGate now, plus I didn't get to test foobar with the DSDIFF plugin last year. Plus we now have DSD decoding on the Mac OS X available with XLD and commercially with DSD Master.

MUSINGS: Gone 4K / UHD - A "Look" At Ultra-High-Definition...

This week, I thought I'd take a break from just the audio stuff and discuss a new "toy" I got 5 weeks ago. That's right, as the title suggests, a 4K / UHD screen; it's a computer monitor to be exact:

A view from behind the commander's chair :-). BenQ BL3201PH on the table.

Remember that there's a separate "body" defining 4K movies at the local movieplex - the Digital Cinema Initiative (DCI). They have "true" 4000 pixel horizontal resolution like the 4096x1716 (2.39:1 aspect), or the very close 3996x2160 (1.85:1) resolutions. Whereas for the smaller screens like computer monitors and TV's, we have the UHD "Ultra High Definition" standard defined as 3840x2160 (16:9 / 1.78:1). So although it's not exactly "4K" horizontally, it's close and I guess "4K" is a better advertising catch-phrase than "2160P". Needless to say 3840x2160 is 2x the linear resolution of 1080P or 4x the actual number of pixels.

MUSINGS: Audiophiles "Us vs. Them" (Objectivists vs. Subjectivists) Attitudes and Envy!?

Since I'm stuck at LAX on my way home from a wonderful Spring Break with the wife and kids down in Texas as well as a Caribbean cruise, I thought I'd polish my response to Hal Espen's comment in the last post... BTW, I enjoyed visiting Bjorn's in San Antonio just to see the audio and home theater gear they had on display. Some really nice stuff and it looks like they're upgrading their main demo room to Atmos soon. I appreciated the knowledgeable staff and friendly attitude; taking time to demo the gear even though they knew I didn't even live in the USA.

So Hal, nice comment:

Pure confirmation bias from beginning to end. None of this really exists. : )
You can't have it both ways. Either your blog is about providing the little bursts of brain chemicals that us vs. them skeptics receive when scientism is seen to be crushing audiophilia, or you're going to go wafting into the subjective realm of the subtle and imaginative "classy" pleasures of reproducing music electronically, as you do with evident misgivings here.

Which side are you on, boys? Which side are you on>

Gets right to the heart of some of the heated debates and arguments I suppose... I guess I "swing both ways" in some regards. :-)

2015-02-27: HiFi Centre Grand Reopening...

About a year ago, I reported on the B&W Nautilus demo at the HiFi Centre here in Vancouver. That was at their old location... As of late February, they're now in the new place near Vancouver Chinatown and to celebrate, they had a nice (re)opening event (February 27, 2015). It caught some publicity from the Stereophile web site as well.

I decided to go check it out after work on the Friday and see the new space. For fun, here are a few cell phone snapshots of some of the gear on display. Note that it was well attended and I purposely tried not to take shots with people in them to protect the innocent :-).

Upon entering the main building, we see a Nautilus "shell" display; HiFi Centre has always had a good partnership with B&W:

MUSINGS: Audio Quality, The Various Formats, and Diminishing Returns - In Pictures!

Let me be the first to say that graphs and charts where audio formats are plotted out in terms of unidimensional sound quality ratings are ridiculously oversimplified and can be very misleading! However, they can be fun to look at and could be used as bite-sized "memes" for discussion when meeting up with audio friends or for illustration when people ask about audio quality.

Since they're out there already, let us spend some time this week to look at these visual analogies as a way to "think" about what the authors of these works want us to consider/believe. I'm going to screen capture without permission a couple of these images to explore. As usual, I do this out of a desire to discuss, critique, and hopefully educate which I consider "fair use" of copyrighted material; as a reminder to readers, other than a tiny bit of ad revenue on this blog (hey, why not?), I do not expect any other gain from writing a post like this.

First, here's PONO's "Underwater Listening" diagram released around the time of the 2014 SXSW (March 2014):

PONO: Underwater Listening

Others have already commented on this of course (here also). I don't know what ad "genius" came out with this diagram, but it is cute, I suppose. I remember being taken aback by this picture initially as it's so far out of "left field" (creative?) that I felt disoriented when I first saw this thing...

How audio formats would evoke a desire to compare underwater depths remains a mystery to me. Obviously, there's a desire to impress upon the recipient two main messages - a direct correlation between sampling rate (from CD up) with quality, and to make sure the MP3 format gets deprecated as much as possible (1000 ft?!). On both those counts, this image gets it so wrong, it's almost comedic. Clearly, one cannot directly correlate samplerate and bitrate with audio quality because the relationship isn't some kind of linear correlation. Why would CD quality be "200 ft", and 96kHz "20 ft"? Surely nobody in their right mind would say that 96kHz is 10 times perceptually "better". Sure, there is a correlation such that a low bitrate file like 64kbps MP3 will sound quite compromised with poor resolution, but without any qualification around this important bitrate parameter, how can anyone honestly say that all MP3s sound bad? I might as well say that Neil Young's a poor-sounding recording artist because the Le Noise (2010) and A Letter Home (2014) albums are low fidelity.