Recording - March 2014 - 39

Earthworks QTC50 HDM Microphone
When the folks at Earthworks inquired if I
would like them to send me any of their mics
to use with the 521 ZDT, I went right to the
big gun-the company's flagship model,
the QTC50. It's been a long while (over 15
years!) since a QTC mic was in our pages,
so our readers deserve a refresher!
The prefix QTC stands for Quiet Time
Coherent, and HDM stands for High
Definition Microphone. Both sum up the
Earthworks' paradigm nicely. "Time
Coherent" is how Earthworks explains its
miniature omni capsules' sound. Unlike
traditional large and small diaphragm
mics, the QTCs do not "smear the time
domain". Essentially, due to their size,
they are fast enough that capsule's resonance stops when the sound does.
As a drummer I totally get this. When
you hit a small, tightly tuned drum head
the sound is quick and short. As you
move to bigger drums the sound rings
longer with more overtones and harmonics. Microphones follow similar principles-smaller means faster damping.
"Quiet" refers to the microphone's self
noise of 22 dB, making it one of the company's best choices for quiet sources. It
can also handle 142 dB SPL, so it's
equally well suited to loud sources.
And "High Definition"? With a frequency response of 3 Hz to 50 kHz, it

hears things you can't. There is no point
looking at a frequency plot unless you like
straight lines-the only slight 2 dB dip is
well beyond the range of human hearing.
The mic has a milled stainless steel
enclosure with a purple ID band. It measures 9" x 7/8" and tapers down to 1/4"
where its 6mm capsule lives. It's available
singly ($1399) or in pairs ($2999), with
mic clip in a felt-lined wood box.
I used the pair of QTC50s on drum
overheads, room duties, acoustic guitar,
piano and backing vocals. I also compared them side-by-side with a pair of
Neumann KM84s, another mic known
for its flat frequency response. The
KM84 is cardioid vs. the QTC50's omni
pattern, so the comparison is imperfect,
but served to highlight the QTC50's
width and depth vs. the focused and
weightier sounding KM84.
To my ears Earthworks mics are very
much the "straight wire" of mics, very
honest and non-source-specific. As an
omni mic, the QTC50 has zero proximity effect and almost no off-axis rejection.
They excel at stereo work; I enjoyed
playing with various techniques. Inches
from a source in a tight pattern yields a
very intimate dimensional recording,
while a wider (17 cm apart) pattern or
even a medium spaced pair a few feet
back gives your source a nice open

depth. (We can't really call these "XY" or
"ORTF" patterns, as these aren't directional mics, but those terms will give you an
idea of how I placed them.)
In all instances I like how they capture
the sound of the instrument-not in a dry
sterile way, but with a nice touch of space.
While I don't typically use a stereo XY
setup for backing vocals, I tried it and was
surprised at how effortlessly they naturally
placed the voices back into the mix.
Interestingly I did not like them as much
for traditional distant mic room duties,
especially on quieter sources where they
highlighted too much room noise that
mics of this sort pick up. The QTC50 is
very unforgiving in this role.
My favorite use was on drum overheads. On cymbals they capture the harmonic nuances of the splashing metal
very honestly thanks to their 50 kHz
range. This is in contrast to many mics
that highlight high frequencies louder
rather than more extended high end. As
such a pair of QTC50s are the cornerstone of Earthworks DK50/R drum mic
package.
I knew the QTC50 was going to be a
critical and honest mic, but I was not prepared for how much fun the pair could
be! Mics such as these inspire artistic mic
placement and creativity, and capture it
impeccably!

http://www.adam-audio.com http://www.adam-audio.com

Recording - March 2014

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