Recording - May 2018 - 26

beyerdynamic
Looking

Taking the ball grille off (see the photo on page 28), the
first dramatic thing I noticed is that there is absolutely no
foam inside-not even a thin layer of foam on the interior of
the ball. Since foam degradation is the number one maintenance headache for stage microphones as they age, it is a
wonderful thing to see a microphone designed without interior
foam. Somebody wanted this mic to last.
The capsule is similar to that of the older beyerdynamic
microphones, with a very small but very highly tensioned ribbon.
The ribbon is not corrugated in the conventional RCA way with
perpendicular corrugations, but is stamped with a pattern that
beyerdynamic claims reduces breakup effects and makes for
more even motion. The ribbon resonance is very far up into the
treble range rather than down at subaudible frequencies like with
the RCA designs. You can tell, just by watching the ribbon as you
tap the microphone body, that there is considerable tension on it.
Behind the ribbon is a vented chamber that makes the
microphone less sensitive from the rear and turns the natural
figure-8 pattern of the ribbon into a hypercardioid. It appears
to be CNC machined rather than diecast, for good consistency
between units. In front of the ribbon is a plastic "blast filter"
which is cemented in place. This not only prevents damage
from people blowing into the mike and P-popping, but it also
creates a second resonance that brings up the high-frequency
response of the system.
All of this is similar to the previous beyerdynamic ribbon
microphones. The step-up transformer, however, is not mounted
into the ribbon assembly itself as in previous beyerdynamic
designs. It's connected via short flexible wires to the contact
points on the ribbon assembly (what RCA calls the "motor").
The transformer appears to be an improvement over the
older beyerdynamic designs, although I did not remove it
to measure it in isolation on the bench. Some considerable
changes have been made in high-ratio transformer design in
the past decade or two, and these changes have not passed
the beyerdynamic engineers by.

Measuring

beyerdynamic has for many decades provided individual
frequency response plots of their microphones with each unit,
and they are continuing to do that. Not only that, the plots
are actually pretty accurate, and while they show a few signs
of smoothing, they represent the actual on-axis measurement
of the microphone pretty well.
My measured frequency response (see the graph) matched
the curve supplied very accurately up to about 10 kHz, and
above 10 kHz even tiny changes in microphone angle
resulted in dramatic changes to frequency response. This
is as one might expect for a ribbon design; small resonances at
high frequencies caused by reflections off the magnet assembly
cannot be eliminated, because the magnets cannot be moved
away from the ribbon.
26

RECORDING May 2018

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