Josephson C720, Manual, Page: 3 / 13

The Josephson C720 is the latest in the Series Seven range of large diaphragm
side ‐ address microphones. It uses a dual ‐ cardioid capsule with separate outputs
for the front and back. Dual ‐ diaphragm microphones since the 1940’s have used
a similar principle internally to allow the user to select any desired directional
pattern. The C720 allows greater freedom and versatility by providing an output
of each capsule half through a discrete impedance converter/preamp stage.
Having separate outputs allows each output to be recorded independently,
permitting the pattern to be controlled in mixdown rather than at the session.
The user can make the pattern choice at another location, or another time.
A unique feature of the C720 is its (patent pending) open ‐ cell metal foam basket.
Unlike traditional microphone housings made of perforated metal or screen with
reflective metal support structures, this highly open material protects the capsule
mechanically, provides electrical shielding and some pop and wind screening;
no supporting structure is necessary. A fine acoustically transparent screen
inside the basket helps protect the capsule from breath moisture when the C720
is used as a vocal mic. We were able to avoid using a traditional support
structure because the foam itself is a tough self ‐ supporting aluminum alloy. It’s a
highly open structure so that sound reflected by the basket is negligible, while
the basket still provides full protection for the capsule. Traditional designs
incorporate rings and bars to support the grille material, leading to the reflection
in the left picture. These reflections in turn introduce acoustic resonances in the
microphone response which contribute to frequency response anomalies and