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TECHNICAL DESCRIPTION
The cartridge
Omnidirectional (pressure) microphones DPA 4004 and 4007 use a
12 mm (0.47 in) diameter prepolarised condenser cartridge. The
diaphragm is a nickel foil which has been coated with an ultra-thin
polymer layer for optimum corrosion resistance. The microphone
housing is of German silver, an alloy with a high content of nickel to
match the stable thermal qualities of the diaphragm. The self noise
of the cartridge is typical 24 dB(A) re 20 μPa and the nominal sensi-
tivity of 4004 and 4007 are 10 mV/Pa and 2.5 mV/Pa respectively.
Due to the size of the cartridge it can handle extremely high SPLs,
has an extended linear frequency response up to 40 kHz and a high
degree of omnidirectionality, even for higher frequencies. For opti-
mum stability the microphone cartridge has undergone a special
pre-aging process which releases all tensions in the materials and
stabilizes the polarisation voltage.
The preamplifiers
Types 4004 and 4007 are acoustically identical, but differ in their
preamplifier powering system. The 4004 is powered with 130 V via
the HMA5000 High-Voltage Microphone Amplifier and has a modi-
fied 4-pin XLR-connector (see Fig. 1 for pin designation). This special
powering system enables the microphone preamplifier to handle
approximately 10 dB higher SPL than similar microphone types po-
wered through conventional P48 systems (4004: 168 dB SPL peak
and 4007: 155 dB SPL peak).
Furthermore, the 4004 together with the HMA5000 is a totally
tranformerless system and therefore has an extended low-frequen-
cy handling capability (10 Hz to 40 kHz ± 2 dB). The 4007 is po-
wered via a standard P48 system and is equipped with a high quali-
ty audio transformer and a standard 3-pin XLR-connector (see Fig.
2 for pin designation). Types 4004 and 4007 use state of the art
low-noise preamplifier technology and are driven with unity gain.
All microphones come with an individual calibration chart with the
specifications of self noise, sensitivity and the frequency response.
2
1
Ground
2
Fig. 1. External view of the output connector of the DPA 4004.
Ground
1
Signal -
Fig. 2. External view of the output connector of the DPA 4007.
Important:
The microphone will only operate within it's specifications if
powered correctly.
4
Signal
3
130 V DC
Preamplifier Supply
2
Signal +
3
3
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