|Cute CD BTW for the Simpsons lovers out there...
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?).
A number of manufacturers appear to have no comment (eg. Black Rhodium, Audience), non-committal (eg. Kimber), or answered the question tangentially (eg. Synergistic, Chord). A few had pretty good responses and appeared aware of the technical benefits of I2S (eg. AudioQuest, Vertere). But I found it interesting how Nordost recommends S/PDIF "for best results" based on impedance reasons. And MIT likewise recommended S/PDIF because they somehow have "so much control" over signal integrity! Really? These people do realize that S/PDIF is more than likely the most jittery of all the options provided and the coaxial variant also doesn't provide galvanic isolation, right? I thought jitter was a "bad" thing. Perfect impedance match itself isn't going to affect jitter in a meaningful way no matter how much "control" they think they have in terms of construction of the cable.
Even more curious, consider the response from Crystal Cables / Siltech which I found to be the most disappointing. Supposedly USB and ethernet have wire configurations causing "major jitter and picks up noise". Really? And ethernet "fails as their standard connection is poorly implemented mechanically in regard to impedance and jitter". Really!? So sad... And I was starting to like ethernet after demonstrating signal integrity over >7,300km with essentially no measurable jitter :-).
Would any of these companies please demonstrate an example of how their cable improves quality and presumably reduce the effect of jitter on actual DAC analogue output compared to a decent run of generic cable? Maybe MIT and Nordost can give it a go with their coaxial S/PDIF cables which they have mastery in? Crystal Cables and Siltech make USB cables; how about showing the benefits of their USB compared to the "major jitter" from generic cables?
I wonder if the cable manufacturers have been scared off ethernet due to all the bad press around the "snake-oil" nature of their claims especially last year. Good. I hope they stay far, far away and over time perhaps we'll have the good fortune to see other cable types fall out of favour from silver-tongued hype.
Although much of the comments up to now have to do with the recent Hi-Fi+ "buyer's guide", let's think about this in the broad context and consider the other magazines like Stereophile, The Absolute Sound, What Hi-Fi?, etc... When was the last time writers actually did any controlled evaluation, or questioned the value of expensive cabling even though it's not hard to find consumers and websites like this blog questioning the relevance of the whole "audiophile cable" venture?
I was listening to a radio program a couple weeks back about the evolution of media in general from traditional print-based models to how things have shifted these days with Web-based delivery. One general observation made has been that "investigative journalism" has suffered over the years. So often these days (and not just in audiophilia), articles have become brief announcements or soundbites containing nothing more than product news aimed at garnering "traffic", and often the faster the story is posted, the more clicks it receives as the first to announce. Even with more substantial "review" articles, notice just how much text is devoted these days to comments from manufacturers that look like nothing more than cut-and-paste jobs with much of the content little more than what could be garnered by looking at a manufacturer's website! Ralphpnj on the Squeezebox forum recently pointed to an article describing the rise of "sponsored content" in news media. Indeed, let's just be candid and acknowledge that so much of what we read in the audio world is simply "sponsored content" (obviously that was the nature of the free "guide to cables" above).
Consider for a moment when was the last time you saw a magazine article go in depth into exploring a commonly used word like "jitter". If I just started exploring high-end audio in the last 6 months, reading magazines, joining the typical audio forums, do you think a "newbie" would understand this concept or would he end up confused, perhaps even a little anxious with doubts as to the adequacy of jitter control in his own system? Googling "Stereophile jitter" (giving Stereophile the benefit of being perhaps the most rational of the bunch), he would run into articles from 2004-2009 rather than contemporary discussions. I would hope to think that this state of affair is not something that is acceptable for serious hobbyists nor should ignorance be an acceptable status quo for the press.
About a year ago, I wrote the post "Audiophiles 'Us vs. Them' (Objectivists vs. Subjectivists)". In it, I expressed that from the perspective of how I feel about all this, I'm actually not angry. And I find it hilarious that anyone would even think envy is a significant factor among the "more objective" audiophiles. If anything, I suppose there is disappointment mixed in with disgust. Disappointment with the lack of substance when reading purely subjective reviews and thinking that there's more we could know about a device from the accuracy perspective if only we could be treated with some objectivity to demonstrate just how much effort went into the engineering. And disgust when comments are made by some like these manufacturers above who speak with conviction but not truth. I fully accept that we all have idiosyncratic preferences. Sure, some might prefer vinyl over digital, or tubes vs. solid state, or jazz vs. classical vs. rock vs. pop vs. electronica... But concepts like accuracy and jitter do have objective correlates which must be respected; otherwise the endeavour for something like an electronic hardware review would be incomplete. Without grounding and some form of reality testing, one might as well enter the Twilight Zone or fantasy world where truth and opinion end up undifferentiated. With the audiophile media space lacking in consumer advocates and educators the unfortunate outcome of "sponsored content" is that magazines these days seem to accept on faith claims made by these sponsoring sources no matter how incredible!
I have heard apologists say that "this is only a hobby". And aren't hobbies meant to be "pleasurable"? Of course. But since when are half-truths and at times all-out lies acceptable and ethical conduct, not to mention that many of these instances seem to be part of typical business practice?
Let me end off with a practical challenge to audiophile magazines to perhaps help readers appreciate the effect of jitter. In the article on digital audio by Julian Dunn linked previously in my Chromecast Audio Part II post, consider the following summary from page 34:
It is one thing to be able to identify and measure sampling jitter. But how can we tell if there is too much?
A recent paper by Eric Benjamin and Benjamin Gannon describes practical research that found the lowest jitter level at which the jitter made a noticeable difference was about 10 ns rms. This was with a high level test sine tone at 17 kHz. With music, none of the subjects found jitter below 20 ns rms to be audible.
This author has developed a model for jitter audibility based on worst case audio single tone signals including the effects of masking. This concluded:(Bold added to highlight important details!)
“Masking theory suggests that the maximum amount of jitter that will not produce an audible effect is dependent on the jitter spectrum. At low frequencies this level is greater than 100 ns, with a sharp cut-off above 100 Hz to a lower limit of approximately 1 ns (peak) at 500 Hz, falling above this frequency at 6 dB per octave to approximately 10 ps (peak) at 24 kHz, for systems where the audio signal is 120 dB above the threshold of hearing.”
In the view of the more recent research, this may be considered to be overcautious. However, the consideration that sampling jitter below 100 Hz will probably be less audible by a factor of more than 40 dB when compared with jitter above 500 Hz is useful when determining the likely relative significance of low- and high-frequency sampling jitter.
Perhaps one of the audiophile magazines could take on the task of unpacking the above information and presenting it to the general public. Maybe do some research on what has been done since 2003, perhaps provide some illustrations... Maybe show some J-Test results to explain what the audible thresholds might look like in equipment reviews. I suspect a well done article like that would really become a "primer" of sorts for audiophiles; likely quoted, recommended, and searched for years to come. Imagine how many clicks and how much traffic an article of substance could garner over the years. The impact would be very significant in demystifying what should have never been that much of a mystery to begin with (remember we're looking at the impact of jitter in audio frequencies over wires, not gigahertz wireless telecommunications!). It might even help some of these cable manufacturers understand and test a thing or two before they speak. Of course that's assuming that education and reality testing are within the mandate of magazines these days and that there is editorial freedom to explore beyond the limits of sponsored content or desires of said sponsors.
The other day, I was with my 10 year old son at the local bookstore to see if there was anything he wanted to pick up. Among the usual comics and youth novels, he picked up a book on "cryptozoology"; essentially the "monsters" of this world (even though of course some could be just undiscovered creatures rather than scary). You know, Bigfoot, Wendigo, the chupacabra. As I was thumbing through the book with my son, I could not help but smile and realize that there was more "objective evidence" in the form of fuzzy pictures, footprint casts, shaky videos, strange animal tracks ostensibly for Bigfoot, Yeti, and the Loch Ness Monster that I have ever seen as evidence for the benefits of expensive cabling on sound quality. Testimony of course is just as prominent if not more in the audiophile world. Go figure... :-)
Have a great week ahead. Enjoy the music everyone!