DPA 4003 User Manual page 5

User's Manual
Technical Description
The Nearfield Grid
The Nearfield Grid DD0251 on the microphone cartridge is designed to have
a linear on-axis frequency response for near field applications (see Fig. 3 for
frequency responses measured with the Nearfield Grid). The grid can be
exchanged with the DD0297 Diffusefield Grid or the UA0777 Nose Cone.
The Diffusefield Grid
The Diffusefield Grid DD0297 is supplied as standard. It is designed for diffuse-
field recordings, or recordings in the far field. The grid gives a high-frequency
boost on-axis of 6dB around 15kHz (see Fig. 4) without adding noise to the
recording. This boost gives a linear diffuse-field (far field) response up to 15kHz.
The Nose Cone
The Nose Cone UA0777 is available as an optional accessory . As with the
Diffusefield Grid DD0297, the Nose Cone is simply screwed onto the micro-
phone cartridge in place of the Nearfield Grid DD0251. When fitted, the
Nose Cone gives the microphone a true omnidirectional response even at
high frequencies (see Fig. 7) and a linear diffuse-field response (see Fig. 5).
These qualities are useful at any distance for an even tonal balance of sound
arriving at all angles of incidence, e.g. room reverberation or several sound
sources placed around the microphone. The diaphragm is placed in a slot
behind the solid cone and sound waves only have access to the diaphragm
through the side of the Nose Cone. This way the Nose Cone prevents an
on-axis, high frequency sound pressure build-up on the microphone, which
is the reason for normal flat fronted omnidirectional microphones becoming
more and more directional for higher frequencies. There is however, a slight
high frequency boost on axis.
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