Specifications

19
Boundary-Layer Capsules
diffuse sound field cause the boundary-layer micro-
phone's sensitivity to increase by only 3 dB. Thus a
boundary-layer microphone will suppress diffuse sound
somewhat, even though it is not directional. It will pick
up less “room sound“ and the recording will be slightly
“drier“ than it would be with an omnidirectional
microphone.
The capsule itself is a classic electrostatic pressure
transducer, which assures accurate reproduction of
even the lowest frequencies along with the high sig-
nal-to-noise ratio and stable performance typical of
professional con denser microphones.
This type of transducer is inherently insensitive to
wind and vibration and the BLM 3g is comparatively
heavy, so it picks up very little solid-borne noise. For
example, when footsteps are recorded, most of the
sound reaching the microphone will be conducted
through the air rather than the floor.
Typical applications in clude pickup of stage dialogue,
or in orchestra pits, as an ambience microphone and
for special public address applications. Since the micro-
phone may well be used on the floor, the likelihood of
damage from its being stepped on has been reduced
by careful design and construction. As a rule, the cap-
sule will not be harmed by normal footwear.
The BLM 3g (boundary-layer microphone capsule)
resembles any other microphone capsule of the Colette
series in that it needs a microphone amplifier (e.g. CMC,
CMD 2U or M 222) to form a complete microphone.
This arrangement allows the pad (DZC) and Active
Access ories such as the variable low-cut filter (CUT 1 or
CUT 2) or the Active Cable (KC) to be added as well.
Boundary layer microphones are particularly useful
for unobtrusive recording with A/B (spaced microphone)
methods, but M/S recording is also possible, using the
special MS-BLM accessory (see photo above right).
Dimensions: plate: 200 mm × 200 mm × 5 mm
Height of the microphone-amplifier connector: 21 mm
Weight: 570 g (without microphone amplifier)
Surface finish: matte gray
Accessory (included):
polished wood case
MS-BLM
Setup for M/S recordings with BLM 3g + MS-BLM and
MK 8 + KC Active Cable or compact microphone CCM 8U
COLETTE
modular
Accessory (optional):
M/S double clamp MS-BLM allowing Mid-Side (M/S)
stereo pickup with the BLM 3g in the Mid channel
The MS-BLM can be used when making M/S record-
ings with a BLM 3g. Its larger side holds the micro-
phone amplifier (e.g. CMC) or capsule connector of
the KC Active Cable, screwed onto the BLM 3g. The
smaller side either holds an Active Cable with an MK 8
capsule or a CCM 8 U compact microphone, which
should be placed over the sound inlet of the BLM 3g.
The engraved “8” on the end of the MK 8 or CCM 8
U should lie parallel to the plate of the BLM 3g, and
the red dot should point to the left when viewed from
behind the microphones.
The great advantage of M/S technique is the ability
to make adjustments during post-production. The
“M“ and “S“ channels can be recorded directly, and
matrixed into stereo left and right signals in playback.
The apparent width of the stereo image can then be
set appropriately for the given situation.
Color: gray
Directional boundary-layer recording:
microphone: e.g. cardioid
CCM 4 or MK 4 with
Active Cable
COLETTE
modular
CCM
compact
BLCg boundary-
layer adapter
hemi-supercardioid
hemi-cardioid