Period pain (a second stab)

Does the earth revolve around the sun or the sun around the earth? It is only in the last five hundred years that we’ve known with any certainty the answer to this question. Prior to the 17th Century, most people thought the earth was the centre of our solar system. It would take the work of one Nicolaus Copernicus to convince us otherwise. His 1543 work posited that it was, in fact, the sun sitting at the centre of the solar system. But it would take a hundred years for Copernicus’ heliocentric model to become accepted wisdom. Expert thinking changed and the layman’s thinking, over time, adapted accordingly.

How many senses do humans have? The expert thinking on this subject, often attributed to Aristotle, says five: touch, smell, taste, hearing and sight. However, as early as the 1960s, scientists began to question this finding to later conclude that there may be over twenty human senses. Expert thinking has changed and our thinking is changing with it.

The idea that anything but lamp cord should be used to connect a pair of loudspeakers to an amplifier was once laughable. But no longer. Since the late 1970s, expert thinking has slowly been eroding resistance to the idea that a loudspeaker cable’s materials and construction can influence sound quality. Expert thinking has changed and our thinking is changing with it, albeit slowly and with some pain.

Direct experience pops Paracetamol from the blister pack. For most of us, it’s far easier to audition the result of an expert’s work – e.g. his/her loudspeaker cables – than to understand the thinking behind it. It takes an hour or two to A/B loudspeaker cables but years to become an expert in the field.

Getting picky with semantics for a moment: no cable – or ANY piece of hi-fi gear – can add to sound quality. Everything subtracts from its input signal. Some loudspeakers subtract more than others. Some amplifiers subtract more than others. Some DACs subtract more than others. Some cables subtract more than others.

Does this hold true for digital cables?

For many of us, digital audio is ‘just ones and zeroes’. Audiophile USB cables? Poppycock! But where did these same people pick up the idea that digital audio either worked or it didn’t and that various in-between states of USB audio quality were nonsense? I point an accusatory finger at the early days of the compact disc. It’s a marketing man’s job to sharpen their message’s persuasive power. Could it be that those employed by Sony and Philips back then went overboard with the simplifications? After all, to overthrow existing formats – vinyl and cassette tapes – Sony and Philips would need the most potent of messages. “Perfect sound forever” ought to do it.

No longer do many of us believe in that maxim so why should we hold onto the associated notion that bits are just bits? One reason might be the rise of CD’s popularity moving (seemingly) in lockstep with home computer ownership whose (academic) textbooks back then made no mention of jitter as its relates to digital audio or the isochronous transfer protocol used for time-sensitive USB data. Electrical noise? Exsqueeze me?

For this listener, his colleagues and a large number of audiophiles at large, personal listening experience has laid to waste the ‘bits are bits’ thinking. We assert that USB cables can influence the sound of a hi-fi system, much to the chagrin of those who insist our findings are an impossibility. Before you reach for the gun marked “snake oil”, read this.

What do those who design and manufacture digital audio hardware – the experts – say?

A few weeks ago, I posed the following question to a handful of audio engineers, some of them veterans in the field: Can changing a USB cable alter the sound of a hi-fi system?

Here are their responses:

Matthias Lück (Brinkmann Audio):

Yes.

Gordon Rankin (Wavelength Audio):

Yes.

Garth Powell (AudioQuest)

Yes.

Jürgen Reis (MBL)

Yes.

A Nonny Mouse (XXX) <— wanted to remain anonymous

Yes.

Paul McGowan (PS Audio)

Yes.

Anonymous (XXX)

Yes.

Nuno Vitorino (Innuos)

Yes.

Bent Holter (Hegel)

Yes.

Jason Stoddard (Schiit)

No (but maybe).

Jason Stoddard went on to say: “I think that encouraging USB nervosa amongst most people is (a) ridiculous, and (b) fundamentally anti-growth for high-end. As soon as normal humans hear about this nuttiness, they’ll go right back to their Airpods. And that’s the big loss.”

I don’t doubt that Stoddard’s right. To whom USB cable differences matter is not a trivial concern. It’s why I advocate for beginners to ignore USB cables and come back to them later should they see the need. Not every product is aimed at every listener, especially when they’re just starting out.

In January of this year, Schiit announced Unison — a better sounding (according to them) USB receiver chip for their D/A converters. In the Unison press release, Mike Moffat is quoted as saying: “As a result, Unison USB is now our preferred input over SPDIF. It’s not ‘just as good,’ or ‘close.’ It’s really better than SPDIF. And yes, that’s me saying this, not an alien pod person.” Evidently, even for experts as grounded in their thinking as Moffat and Stoddard, digital audio is still a long way from being ‘just a matter of ones and zeroes’.

For a popular science take on the ‘why’, we click on the work of another expert, AMR/iFi’s Thorsten Loesch, whose ‘USB Audio Gremlins Exposed’ serves as an excellent USB audio primer. The first bubble burst by Loesch is the idea that a USB audio connection corrects for errors — it does not:

“Isochronous transfer mode uses error-checking but includes no re-transmission in case of Cyclic Redundancy Check (CRC) errors. Electrical noise on USB signals causes CRC errors and thus data loss, as does poor signal integrity. In mild cases, this leads to audio signal distortions. In the worst cases, clicks and dropouts. It means that a USB audio device can work correctly only if USB signal quality is excellent and no CRC errors occur.”

And if we as non-experts don’t understand the thinking behind the variability of USB audio quality – or if we deny an expert opinion’s validity – then is it not our responsibility to substitute our lack of theoretical understanding with a little seat time? After all, it takes a handful of hours to perform a listening test but thousands of hours to qualify as an expert.

Could the ongoing contentiousness of USB cables (and hardware like it) be symptomatic of digital audio’s own change pain period?

Before you answer that, how about asking yourself: “Am I an expert?” For me, the answer is a firm ‘no’. And that’s precisely why I seek technical information from those whose audio industry engineering experience runs not only years but, in many cases, decades. And if I trust in those experts to explain what’s going on with my own listening experiences – that USB audio might be fallible and that electrical noise can have a negative influence on a DAC’s analogue output stage – I also trust them when they say that not all audible differences can be measured: