QED, Bitches!!

Agnostics are often assumed to be wishy-washy—that they dither and um when asked about greater things. But actually, an agnostic has a firm belief: they do not have enough information to conclusively be either a believer or an  unbeliever.

I’ve found it instructive to approach audio (and most things) agnostically; believers tend to spend a lot of money, and unbelievers miss out on some amazing moments. I like being agnostic. It makes the field of view rational and fathomable, but leaves the peripheral vision mysterious and unknowable.

And so, when I hear about the amazing things a product or technology can do for an audio experience, I need to ask ,“How?” All I want to know is that the claim is possible in our physical universe. After confirming possibility (versus probability) I am happy to tend toward belief. Yes, I’ve been told I trust too much. Let’s take the example of digital cables. When I first heard about “audiophile” digital cables, I scoffed like a man choking at a Denny’s. After all, a digital signal is either there or not there, right? Can one digital signal be better than another?

However, the problem with asking “how?” is that it’s the same question asked by the people so wedded to their beliefs, that not even blowtorch and crowbar will do them part. As a result, even if you’re careful to not make it sound like a “But… how??”, many industry people get defensive, which, funnily enough, results in a shaky defense of their product. Audio people, it seems, have had so many experiences being buttonholed by aggressive electrical, computer, and self-professed engineers that they can be as skittish as prey animals when asked for underlying concepts. I have to assure them I that I’m asking because I want to believe, not because I want to claw their world to shreds.

And so, when you patiently tell me that a digital cable doesn’t know it’s digital only, and can pick up noise that may not affect the signal, but is piped straight into your audio circuits, at least I have a “how”. When you explain that digital signals are far more complex than the picture in my head of a line of pulses marching down a wire like little soldiers, and when you remind me that a music stream exists in a time domain, I’m happy to have a “possible”, even if I don’t yet have a “probable”.

I once read an impassioned review of audio Ethernet cable that proved—QED, Bitches!!—that all audiophile digital cable is a raging scam. The test? To send a data signal down a few feet of no-name cheapo cable, and then down a few feet of audiophile cable, and check the received packets. Both cables transmitted their data perfectly, and so, concluded the article, you’re an idiot to buy your cable from anywhere but a big-box home-improvement store.

Even as a then-disbeliever, I knew this wasn’t a fair test. My Ethernet cable goes from my NAS in a cupboard, into the attic past furnace and wiring, out again over the tops of the kitchen cupboards, past several fluorescent lights, across a wall and then down to the system—a run of about 50 feet. Surely a better test would be to run regular Ethernet cable and then an audiophile cable along the same path, and then check for data packets? After all, there’s no receive confirmation with UPnP—if your streamer is not hearing the signal every so often because of a burst of EMF from some device near your cable, it’s going to either drop, or do God only knows what. And that’s just the first test. Surely you should sweep each cable for noise at all reasonable frequencies, and see if the audiophile cable is less noisy? I’m not even going to mention a listening test.

Apart from forgetting to look at cable in the context of an entire household versus just the march of voltages down a wire, many “digital is digital” rants and reviews forget that a music stream has time as part of the signal. Seventy four minutes of audio on a CD has to stream into and out of a DAC in exactly 74 minutes, but can be transferred as data in seconds from a hard disk, minutes from an internet server, or just under 90 years by a man on a mountain with two flags by day, and two torches by night.  (Assuming non-stop bit-by-bit transfer at 2 bits a second). All four offer the same data, but certainly not the same musical experience.

About a year ago, I had a demonstration that a digital circuit can continue to receive and process an audibly distorted digital signal. We had a DAC in the store that had a problem with its USB input. We were playing a Michael Jackson tune, and it started out okay, but slowly became a mess, with drum beats at the wrong places, and Michael’s voice sounding like he’d been knotted up at the end of a PVC pipe. This gradual build up of error was repeatable with different sources, but only on the USB input, S/PDIF was fine. If such gross distortions can get through, what other more subtle artifacts are passing through your pristine “bits are bits digital is digital it’s either 100% or 0” audio stream right now?

I am guilty, like so many, of generalizing this “it’s either on or off” bit-level view of digital to every aspect of digital design. I assumed that the digital side of a DAC, for example, was either going to work perfectly or not work at all, and levels of quality can occur only in the analog section or in the resolution of the music files. This is untrue, as I learned last week when I went back to Copper #1 and started reading my way through Richard Murison’s “Quibbles and Bits” column—something I’d promised myself I’d do when I was slapped by the term “ladder DAC” just after RMAF 2017.

Reading the column and pretending to understand how a Sigma Delta Modulator works (the weak link being me, and not Richard’s clear and cogent text), I realize how much wing, spit, and prayer there is in digital circuit design. If like me, you’ve made an “impossible” upgrade to your system’s audio quality (such as when I deemed my DIY isolation platform too ugly to be on the main audio rack, and idly placed it under my NAS), then the agnostic in you should rest assured that digital may be rooted in binary, but is most certainly not black and white.