Part III: What Is It That We’re Hearing, Anyway?

As We Were Saying . . .

For the last two months I’ve been trying to offend everybody by suggesting some unkind things about the audibility of high resolution audio, taking the position that hi-rez isn’t a very audible improvement, compared to 16-bit or even analog audio. I’ve tried to also explain why there’s such a fuss about hi-rez (it’s because we CAN hear it, a little, and we’d like to think THAT makes IT important and US cool).

This month I’d like to discuss what it is we probably do hear, when we listen to our favorite hi-rez audio and are SURE we really DO hear a difference. While most of the limits of hi-rez are well beyond the various thresholds that limit and/or mask our perceptions, we do hear stuff, and it is worth discussing what we do in fact hear.

First, it’s gotta be admitted right up front, that some of the hi-rez goodnesses we hear are imaginary. Now that doesn’t mean we don’t really hear them, or that they aren’t important to us. But you’ve gotta understand that we hear things, with that remarkably complex multifaceted hearing system of ours, things that sometimes aren’t there physically. We are really good at extracting meaning out of chaos, and sometimes we extract meaning from signals that really are, well, just chaos. Signals that don’t actually have any meaning in them.

There’s nothing wrong with this. Such cognition is an essential part of survival by making quick sense of the world around us, and so, when we feel like we’re really picking out the 24th bit down there in the noise, as a function of those super-detailed reverb trails and awesomely evanescent images floating there in our mind’s ears, we may very well be just making it up. In any case, we are almost always guessing when we are trying to pick out these really small differences.

But there’s more to this. Along with the imaginary, there’s the real stuff, too. We hear things, remarkably well, and some of my golden-eared brothers and sisters can hear some amazing audio details. I could tell you stories . . .

However, exactly WHAT it is that we’re hearing is a different question. Some of it is relevant to hi-rez audio, some of it isn’t. As reader Dave Riddle pointed out to me a couple of months back, when we glory in the good ol’ analog sound of the 50s and 60s (when, believe it or not, there were some really great recordings made) maybe what distinguishes the sound isn’t the clean, robust analog signal flow at all, but instead the 20-50 transformers hung (at every device’s input and output points) along the signal path. Maybe the sweet fatness of those sounds is all in the transformer windings!

See what I mean? All this time, we’ve assumed it was the analog purity, when actually it might just as well have been the stupid transformers. In our brave new hi-rez world, similar things play. When we compare a 16-bit box to a 24 bit box, we may hear a difference, and that difference may have nothing to do with word-length. It may be that the 24-bit piece’s manufacturer used a “better” grade of capacitors, or maybe they didn’t use capacitors at all, or maybe, even, they used TRANSFORMERS! Meanwhile, we say, “Man, doesn’t 24-bit REALLY clean up the sound? Awesome!!!”

Sometimes, also, it is in fact the hi-rez. I have a colleague who recently told me, “Boy, 24-bit really makes a difference. Mixing is SOOOOO much easier!!” As we were both drinking at the time, this had the makings of a really interesting discussion. But when we got into it, it turned out he was talking about mixing in a DAW. And he wasn’t just knocking together a voice track, a music bed and some FX. He was mixing A TON of tracks, all with heavy processing. And so his observation was quite reasonable – that the extra word-length really seemed to make a difference in terms of transparency when he started combining all those gazillions of tracks. He really noticed it when he got stuck with 16-bit resolution in this kind of production environment.

Now, my colleague may be imagining it, but he seems sure enough of his ground that I’m inclined to believe he really hears it. And it IS reasonable that he should – the additional word-length does provide some distinct advantages when dealing with the accumulating errors that build up when lots of tracks ‘n processing are all happening at once.

So, it seems to me we can reasonably assume that in conditions where there are massive digital accumulations of rounding errors, processing artifacts, and level changes, hi-rez is good. I assume, also, that there may be other instances like this, where the presence of hi-rez keeps us out of audio doo-doo that would turn out to be audible, perhaps quite disturbingly audible.

There is another instance where I’m also sure we could hear it – loud and clear. And it’d sound great, if we could afford it. If we built up our analog gear and our loudspeakers so that the Least Significant Bit (the 24th one) equaled the analog noise floor (-100 dBV) and the threshold of hearing (0 dB SPL), why, then we’d hear this hi-rez benefit for sure. Personally, I think it would be fabulous!

Our normal calibrated listening level would then be, of course, something like –60 dBFS for 84 dB SPL, and our loudspeakers would require water cooling and our power amps would have to be capable of generating perhaps a mega Watt of power per channel – they’d probably need water cooling as well, maybe even liquid hydrogen.

The enhanced headroom of such a system would be absolutely glorious. And audible, I’m absolutely sure! Particularly when we decided, after a couple of double tequila sunrises, to really crank it! Too bad it’s not practical, or affordable.

Next month we’ll wrap this up, talk about the meaning of it all. In the meantime, keep in mind that on Thanksgiving Day as on every day, we are what we eat.