Gordon Holt once told me, “Depth is always the first thing
that goes.” By this he meant that when you change something in the signal chain
that has less fidelity than the component it replaced, the first indication of
this is the loss of depth cues. Holy collapsing soundstage Batman!
Of course, you need a recording that has natural depth to be
able to detect subtle changes in depth reproduction. That leaves out 99% of pop
and rock albums. Sorry folks, but there’s just ain’t no Jimi Hendrix (or Bill
Monroe) album on earth that will tell you anything meaningful about a system’s
depth reproduction. All the depth cues are artificial. And although some
instruments seem to be farther behind others in the mix, that’s merely
different settings on the reverb.
To judge whether a system can accurately reproduce depth you
need a recording that has coherent phase information. That eliminates most
multi-miked recordings as well, regardless of genre.
Multiple monophonic mics pretty much guarantee conflicting
phase and locational cues. Some audio enthusiasts go so far as to make their
own phase-coherent two-microphone stereo recordings for reference. That’s what
But if making your own recordings isn’t on the horizon, I
recommend MA Recordings as a good source of recordings that accurately capture
the entire sonic picture. Heavy Metal and Electronica fans, be forewarned –
most of their catalog is acoustic music, be it jazz, classical or ethnic roots.
Funny, off the top of my head I can’t think of many rock albums
that I would use to evaluate depth. Dire Straights “Telegraph Road?” That’s artificial
depth, and no matter how artfully applied it’s still not as useful as the real
What do I listen for to “hear” depth? On my own recordings I
listen for instruments, voices, and the wall and floor reflections to all be in
the right places. I know where all the players were during the recording and I
expect when I play back the recording they are in those same places. Has the
playback chain foreshortened the recording space so the instruments all seem to
be on top of each other, or homogenized into a single wall of sound? Does each
instrument seem three dimensional or flat, like a paper cutout? Is the front of
the stage width correct? Do I hear the wall, floor, and stage reflections
coming from the right spots?
On commercial recordings I’m listening for the same sorts of
things – do the instruments and vocalists have dimension and weight, or are
they flat and without form? But since I wasn’t at the original sessions I must
extrapolate where I think the instruments should be based on the sound and
whatever pictures of the session might be in the liner notes. Harder, but hey,
that’s how most critics do it. J. Gordon Holt had an advantage – he had a
library of his own recordings for reference.
But the important thing is – listening for depth isn’t that
tough. It’s a skill, and with practice most normal human beings can get very
adept at it. Many audiophiles get to the point that with a single reference
recording they can not only tweak a system, but also tell you what’s wrong with
any system they play their recording on. At least that’s what they tell me. And
since I have some of my own live recordings that tell me 99% of what I need to
know about a system after a couple of listens, I understand where they are
To tidy things up – If you want to get down into the minutia of
subjective audio you’ve got to consider depth as one of the most telling sonic