Recording - May 2020 - 60

INSIDE
THE BOX
with Joe Albano

MICROPHONE AND
PREAMP MODELING

his month's theme, instrument miking, may seem to be
entirely an outside-the-box topic, but even this last bastion of the analog domain-microphones and mic preamps-has been incorporated into the virtual studio world! Of
course, you'll still need a physical microphone and mic preamp.
Still, if you can't afford a mic closet full of the best classic mics and
hardware, thanks to the miracle of modeling technology there are
virtual options available.
Advances in circuit modeling now do a very effective job emulating the sound and response of analog EQs, compressors, guitar
amps, effects, and even magnetic tape and tubes. Until recently,
microphones (and to an extent, mic preamps) were another matter.
With a microphone, you need to consider its frequency response
both on and off axis, its transient response, harmonics, and proximity effect. There is also the interaction between the mic's output
impedance and the mic pre's input impedance. All these things
subtly (or not so subtly) color the tone and character of the mic.

60 RECORDING May 2020

Modeling

Several companies have accepted the challenge
of modeling the sound and response of some of the
most classic vintage microphones-the kind that you'd
probably have to mortgage your house to be able to
afford in the real world. While there are software-only
options, the best solutions combine both software and
hardware components, to take mic modeling to the next
level, so that's what I'll be talking about here.
Mic modeling packages all start with a dedicated
source microphone (some with special cables) and a
software (plugin) collection of modeled classic/vintage
microphones. The microphones are typically clean and
neutral, and can even be used on their own merits. They
do not need to be ruler-flat reference mics, however.
As with the room calibration software we looked at
in last month's column, all of the mic's characteristics
and specs simply have to be known so that they can
translate between the mic's inherent response and the
response and character of the mics being modeled.
All of the various mic modeling packages include a
large diaphragm condenser (LDC), and most of the mics
modeled fall into that category, along with a few optional ribbons and dynamic mic choices for variety. Antelope Audio and Slate Digital offer a small diaphragm
condenser (SDC) option as well. The source mics are
high-quality mics in their own right-you can't fake
some things, like good transient response and clarity-
but in combination with the software, they really shine.

Special Features

Many large diaphragm condenser mics utilize dual
diaphragms-their signals are blended inside the mic to
provide multiple polar patterns (directional characteristics), usually through onboard switches on the body of the
mic. Some modeling mics move that capability into the
software, where the patterns can be selected virtually-
even in playback. Instead of the combined signal from the
front and rear diaphragms being mixed within the mic,
those signals are output separately, via a special (included) cable that breaks out into two XLRs. The mic's signal
is recorded as two separate tracks-one for the front diaphragm, and one for the rear. Both signals need to be
captured with a pair of identical preamp/interface channels. As long as the relative levels of the two signals are
maintained, you can select your polar pattern in the software even after the signals have been captured. This also
allows for improved modeling of the originals' polar patterns and off-axis responses. Some companies even model
the specific proximity effect of the originals (in directional
modes). This allows for more accurate results when closemiking instruments or when used on vocals. The flexibility
is impressive, and the quality of the emulations can be
surprisingly close to the original models.

Recording - May 2020

Table of Contents for the Digital Edition of Recording - May 2020