Inside Audio: Dave Moulton
Hi-Res Listening
Alert readers will recall that, about a year ago,
I wrote a series of pieces on high-resolution audio and its place
in the scheme of things. My position was that, especially for television,
it wasn’t particularly important.
I took a fair amount of abuse for that position and
got into a fairly lengthy exchange with a top-level post production
guy as well as Bob Dixon of NBC Sports. All this was duly reported
in the pages of TV Technology. You remember, right? Sure.
Well, a year has passed – a tumultuous year.
And one of the many bits of tumultuousness in my life was the resumption
of a life project that has been lurking in the background for 20
years or so – composing music. And that composing, in turn,
led to a major upgrade of gear.
So now I am the proud possessor of the latest, hottest
Pro Tools workstation, capable of at least moderately "hi-res"
work (24-bit, 48 kHz audio) and a lot of tracks. Further, I’ve
got some pretty hi-res plug-ins (including SpectraFoo, which means
I can really measure the res) and a hi-res reverb (Lexicon 960),
all working within the workstation platform.
All of this talks to the real world through a Yamaha
02R console, which has 20-bit resolution.
More to the point, I’m busy composing some pretty
high-tech, hi-res electronic music. This is music that uses a lot
of tracks (64 plus) for a long time (up to an hour) with a lot of
automation, a fair amount of signal processing, a tremendous amount
of Surround Sound stuff (all my music is multichannel with a vengeance)
and a huge dynamic range (uh, 96 dB!).
What this means is that I’m really and truly
walking the walk these days, not just talking the talk. And so I
thought I’d share with you what I’ve noticed, now that
I have been dragged kicking and screaming into the 21st century
of hi-res audio.
DO YOU HEAR WHAT I HEAR?
The first question has to be, of course, can I hear
a difference with all this increased resolution? And the answer
is, interestingly, yes. Well, sort of yes, anyway.
CDs passed through the workstation sound distinctly
better than CDs converted to analog by the CD player. Soundfiles
imported into the workstation sound really nice on playback.
And what do "sound better" and "sound
really nice," mean? To me, they mean slightly richer, more
luminous, with greater depth and detail than I normally experience.
But it is only "slightly," suggesting that
the difference is, in fact, pretty small.
And finally, I have to ‘fess up, I’m not
sure I could reliably pick out the difference all the time in controlled
blind comparison tests. It may "sound really nice," but
is it "enough nicer" that I could pick it out 95 percent
of the time?
I’m not at all sure that it is.
AUDIO CRYPT TALES
But there’s more to this. At one point this summer,
a colleague (Roger Talkov of DVD Labs) brought in a major label
classical surround 24/96 DVD-A he was mastering so he could check
it out over my surround monitor system. We used a fairly cheap consumer
DVD-A player and just plugged it into my surround monitor path.
Surprise! There was a lovely soft "depth"
and musical richness to the sound that was both distinctive and
satisfying. Further, we were able to compare a (Grammy-winning)
pop 16-bit/44.1 kHz CD against a 24-bit/96 kHz DVD-A release of
the same album and observe that a similar difference seemed to be
present – a softness, a kind of delightfully crunchy musical
depth that replaced the "edge" on the recording. Like
I said, it was really nice.
What causes it remains a question. For reasons I’ll
get to in a minute, it can’t be the bit depth. My speakers
are good to 17 kHz but roll off steeply above that, so I’m
dubious that it is the increased bandwidth.
The stock converters in the cheap consumer player
can’t be any great shakes. So it remains a question, a good
question.
Meanwhile, the music I’m working on has some
serious dynamic range. One piece that I recently finished actually
starts at -90 dB FS and slowly rises to -60 dB FS (and then, VERY
slowly, crescendos all the way to 0 dB FS – but that’s
another story).
What’s interesting is that it is usually very
hard to hear the -90 dB FS stuff. Hard enough that one early listener
called me to wonder why the music didn’t start for the first
several minutes. And when I got the stuff mastered for DVD surround,
the mastering facility called to ask me where on the tape the piece
started – they weren’t sure, even though I had it logged.
Now, -90 dB FS is the 15th bit – some 9 bits
and 54 dB above the 24-bit digital black noise floor of the workstation.
WHAT DOES IT ALL MEAN?
And the truth is, we can’t hear even that crass
"lo-res" bit, under any reasonable playback circumstances,
without anything else going on! Interesting, eh?
What’s the point? Well, I personally think that
the point is that we don’t understand, yet, what it is that
we’re doing with hi-res.
Our hi-res efforts are, apparently, affecting the
quality of sound in ways unrelated to bit depth or bandwidth. We
speculate, rant and dither about what "those ways" are,
but the truth is that we really don’t know. And – truth
be known – it’s pretty subtle, however pleasurable.
A second, more important point, to me, is that Surround
Sound is very powerful medicine – much more powerful, more
pleasurable, more meaningful than hi-res. And yes, we can instantly
hear the difference that it makes. No question at all.
My final point is that you can, if you wish, check
all of this out for yourselves.
Four of my pieces are on display through Feb. 10 as
"virtual sound sculptures" at the Chapel Gallery in Newton,
Mass. If you’re in the area, stop in and check them out –
no charge. The pieces are six-channel Surround Sound compositions
(I use an overhead channel in addition to a standard 5.0 array).
Various listeners have told me that these pieces are
really very beautiful. I’d love for any of you who can to have
a listen and tell me what you think. For info on the exhibition,
contact SeanMacLean@earthlink.net
or http://www.bostonsculptors.com/.
Thanks for listening.
Dave Moulton is busy composing music these days.
You can complain to him about anything else at his Web site, moultonlabs.com.
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