Recording - October 2021 - 34

REVIEW
Zeppelin Design Labs
Cortado MkIII
Contact Microphone
Stick it, clamp it, record it, create!
REVIEW BY PAUL VNUK JR.
eppelin Design Labs is a Chicago-based purveyor of DIY music
products. If you have ever considered building your own amp,
effects pedal, or synth, this is the place to look. ZDL also offers
prebuilt options and this month, I am looking at the Cortado MkIII Contact
Microphone, a pre-assembled alternative to the DIY Cortado MkII kit.
Contact
The Cortado MkIII is a contact (piezo)
mic. A contact mic is just that; it uses a
passive transducer to capture sound from
vibrating surfaces rather than using membranes,
diaphragms or ribbons to convert
sound waves into electrical signals.
Historically, piezo-based contact mics
have been used as pickups on acoustic
stringed instruments, as triggers on
electronic drums, or often as the basis
for amplifying sound on homemade
instruments and found objects.
Caveats
On the plus side, contact mics do not
pick up room noise or leakage, they
are small and can fit in tight and odd
spaces, and you can even use them underwater.
On the flip side, they can be
pretty lo-fi, and their sound and success
will vary from surface to surface. They
are also prone to stray vibrations, and
even bumping the attached cable can
produce sonic crackles and thumps.
Cortado
A piezo microphone in its raw form is
a high impedance device. The Cortado
MkIII is balanced and buffered with an
external phantom powered preamp box.
As mentioned, the Cortado MkIII is the
commercially crafted counterpart to the
DIY Cortado MkII. With the MkII, you build
your own external preamp circuit. The
34 RECORDING October 2021
premade preamp on the MkIII comes in a
rugged 3.25 " x 1.5 " x 1.63 " steel chassis
with attachable rubber feet. There are four
dip switches on its underside for activating
a -10dB pad and a bass boost, which actually
disengages a high-pass filter.
Attached to the preamp is a 6' shielded
cable that terminates in a 1.25 " sensor
element that looks just like a lip balm tin.
The Cortado MkIII boasts specs of 23
Hz - 40 kHz, which refers to the spectrum
that the Cortado MkIII picks up-
not what it sounds like; what it actually
sounds like is dependent on proper
placement and secure coupling on a
good resonant surface.
Mount up
To work, a contact mic needs to sit on
or be attached to a resonant surface-a
sheet of metal, the wood body of an instrument,
the head of a drum or even the
inside of a tin can. The better contact the
mic has with the surface, the better it will
sound. The Cortado comes with sticky
transducer mounting putty strong enough
to keep the mic in place but still be easily
removable. I would be cautious and test
it on the finish of any high-end instrument.
Zeppelin Design Labs also offer an additional
Attachment Accessory Kit ($25) that
includes additional gobs of sensor putty, a
4 " spring clamp, a screw-on metal brace,
and two disks of really strong double-stick
tape for more permanent scenarios.
Sound
I would best describe the sound of the
Cortado MkIII as lo-fi, band-limited and
nostalgic, but still more flexible than a typical
carbon or crystal mic. The critical thing
to note: placement and a proper resonant
surface matter 100% of the time.
Guitars
Starting with acoustic guitar, when I
stuck the microphone right onto the bridge,
it produced a thin, tinny sound with zero
low end. Placing it right below the bridge
on the body gave it a fuller sound reminiscent
of old 1920s blues field recordings.
When I stuck it on top of the pickguard
near where the neck and the body join, it
sounded distorted and rough, almost like a
broken electric guitar, which tells me that
perhaps my pickguard might not be that
well attached to the guitar. Piezo mics have
been used to amplify stringed instruments
for years; proper mount in the proper location
can yield fuller fidelity results.
On the body of a Fender Telecaster,
again below the bridge, the sound of
the strings chimed through cleanly with
a gentle transistor radio sound. It was
similar on my Rickenbacker 4003 bass,
where I was surprised at how well it retained
the articulation of the strings. Both
instances blended well with traditional
miking techniques for adding extra tone
and edge to the sound. This goes for most
of the sources below as well.
Z
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