Technical Notes; Frequency Response - Sennheiser MKH 110 Manual

INSTRUMENTATION MICROPHONES
MKH110ANDMKH
110-1
Short Description
These microphones are especially designed pressure transducers lor
instrumentation purposes. Only the operating principle 01RF-condenser
microphones allows a Irequency response to extend down to 0 Hz.
Description
Output p lug
Wlring
special microphone in RF-technique
3-pln connector to DIN 41 524
1 = audio. nominal circuit output voltage appx. + 5 V
(MKH 110-1: appx. + 4.5 V)
2 = 0 V (cireuit ground)
3 = + 8 V (voltage supply)
3-pin standard eonneetor 10DIN 41 524
Head = 20 mm 0
Tube = 19 mm 0
Length 126 mm
appx. 90 9
Cable conneclor
Dimensions
Weight
Technical Data
Frequeney response
Acoust:ealmode 01operation
Direetionaleharacteristie
Sensilivityat 1000 Hz
Eleetriealimpedance
al 1000 Hz
Minimal load impedanee
Weighted S/N ratio to
DIN 45 590
Maximal SPL
Powering
Operatingvolt3ge
Current drawn
Temperalure range
MKH110
1.. 20000 Hz
pressure transducer
omnidireelional
20 mV/Pa:t 2 dB
MKH 110-1
0.1...20000Hz
pressure transducer
omnidireetional
2mV/Pa:t3aB
appx.
90 Q
2kQ
appx. 90 Q
2kQ
63 dB :t 3 dB
20 Pa
unbalaneed
8V:t1V
appx. 8 mA
-35'C . + 70'C
47dB:t 3dB
500 Pa
unbalaneed
8V:t 1V
appx. 8 mA
-35'C. . + 70'C
Frequency Response
~.:Ek~.~-~~~t~--l~.~I:~~~~
- Hz- QI I 10 100 1000 10000 '0000
Standard Irequency response with tolerance limits MKH 110-1.
The original diagram is delivered with each microphone 01this type,
measured lrom 40 to 20000 Hz.
The Irequency response in the range 010.1 Hz to 40 Hz is checked with
a piston-phone by uso
We reserve the fight to alter specitications. in partieularwith regard to technieallmprove-
menls.
TECHNICALNOTES
High Frequency Circuit
The capsule 01a RF-condenser microphone presents, contrary to
low Irequency circuits, a low impedance output. Instead 01the high
polarization voltage normally required, a high Irequency capsule needs
only a high Irequency voltage 01about 10 V, wh ich is produced by a
built-in low noiseoscillator
(8
MHz).
The low capsule impedance leads 10
a high perlormance reliability 01the microphones.
Powering and Connection
For powering the special microphones MKH 110 and MKH 110-1 a
corresponding power supply MZN 16 X is provided. In order that the
Irequency response cannot be limited by the value 01the output coupling
capacitor, the audio output on pin 1 01the microphone is connected
directly to the output amplifier without a blocking capacitor. There is,
therelore, a DC-voltage on this pin against ground. An amplilier may be
connected using a corresponding capa citor. With a given amplilier input
impedance rand the -1 dS point at the lower Irequency limit Ig, the
capacitor value is determinated by the lormula: 1
C-
. - Jt (r
+
90 Q) Ig
.
: To prevent ground loops, pin 2 (circuit ground) is not connected with the
, housing 01the power supply respectively the microphone. Acorres-
ponding connection - il not already incorporated - has to be providep
(Fig.1).
Connection to Amplifiers with Powering Facilities
11 an appropriate voltage source is available in the amplilier the condenser
microphone can be powered directly. The voltage should be 8 V :t 1 V.
It should be so stabilised and liltered, that the unweighted noise voltage
is< 10 ftV at 8 mA current consumption (Fig. 2).
Irom power supply
ov
Fig.1
.~
.
2~ I'
I(QJI
amplifter
Fig.2
+8V
OV
amplrller
Input Sensitivity and Input Impedance'
Sennheiser special condenser microphones can be connected directly to
all amplifiers whose input impedance is > 2 kQ. 11 the input impedance is
lower, a resistor 01appropriate value should be placed in series with the
microphone to provide correct matching. The voltage division caused by
this series resistor must 01course be considered.
11 the amplilier being used has a too high input sensitivity, it can be
I
'
necessary to reduce the output voltage Irom the microphone by means 01
i
a voltage divider. This should be built at the amplilier input and must have
a total impedance 01at least 2 kQ. Sy this means the large signal on the
I
microphone cable is maintained up to just belore the amplilier, wh ich
helps to increase the signal to noise ratio.