Recording - December 2015 - 32

B Y PA U L V N U K J R .

Advanced Audio CM49
Multi-Pattern Tube Condenser Microphone
This beautiful mic is filled with inspiration-not imitation
Based in Summerland, British Columbia, Advanced Audio is a
microphone company run by respected Canadian mic modder
Dave Thomas. Dave has 45 years' experience tinkering, tweaking,
repairing and building microphones of all shapes and sizes.
Advanced Audio takes the hybrid approach of mic manufacturing,
where models are imported from Asia, customized in-house with
upgraded components, and then turned to Dave's specifications.
Advanced Audio offers a line of mics, both tube and solid state,
that are inspired by the classics. Arguably Dave's best-known mic
is the CM12/CM12SE. Built to evoke the sound of the AKG C12
and to some extent the Telefunken ELA M 251, this mic started life
as a well-known Dave Thomas modification of the Apex 460.
Now serving number 49
On the Neumann side of things, of course the U series gets
most of the attention, but another classic that pops into the picture on occasion is the Neumann M 49. Introduced in 1949, the
M 49 was used and well loved in orchestral, jazz, and vocal
sessions in the 1950s and 1960s. It was a favored mic of
Columbia engineers when recording icons like Bob Dylan or
Simon and Garfunkel, to name a few.
Beyond its full robust sound, one of its notable features was
that it was one of the first multi-pattern tube mics where the pattern could be switched remotely at the power supply. That's a
feature that we take for granted now, since almost every multipattern tube mic on the market does its pattern control this way.
As you can guess, Advanced Audio's CM49 is the AA take on
this classic. However, Dave is quick to point out that the CM49
uses modern components and construction techniques; this is not
a clone and is better described as "inspired by" the M 49.
Looks, body and build
All of the AA models start with imported bodies and windscreen
assemblies; they all share a similar brushed-nickel look that we
have seen on other mics from competing companies. Having said
that, however, the mics are solid and well put together. I appreciate that rather than using the same body assembly for every mic
they sell, as some companies do, AA uses style-appropriate bodies
and windscreens when possible. That includes the long thin body
on the CM12, a rounded head basket on the CM47, and the modern slanted windscreen on the CM67 and CM87.
The original M 49 was a squat fat little microphone with a slanted head basket, and Advanced Audio follows suit with CM49.
The mic measures 2" in diameter and 7" tall with 3" of that being
taken up by a large slanted windscreen. The company logo and
model number are etched into the front of the mic in black.
On the inside, the microphone uses standard 2-bar bracing,
with the circuit board and tube in the center. The tube is an
Electro-Harmonix 6072a, which AA points out is a very low
noise hi-fi tube. Integral to Advanced Audio's sound is the company's custom-wound BV18 output transformer, which is an iron
and nickel dual bobbin design.
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The capsule is a center-terminated 32mm 6-micron thick dual
diaphragm design with a single backplate. It's dubbed the
AK47, a copy of the Neumann K47 found in the original
(although that one originally was called a K49). The mic has 9
selectable polar patterns, centering on Omni, Cardioid and
Figure-8 with interim points in between.
The CM49 comes in a hard-sided aluminum briefcase with a
standard nylon band shock mount, external power supply,
foam windscreen, multipin cable, and leatherette mic pouch.
Technicalities
Specwise, the CM49 has a frequency response of 25 Hz to
20 kHz ±3 dB, 17 dBA self noise, a 200Ω impedance, distortion < 1% @ 128 dB, and an output level of +24 dB with less
than 1% distortion into a 1.2kΩ load.
Looking at its cardioid frequency plot, the mic starts with a
subtle 2 dB bump on the low end at 60 Hz, then has a couple

Table of Contents for the Digital Edition of Recording - December 2015