DIRECTIONALSTUDIO

MICROPHONEMKH816TU-3

Delivery: 1 microphone

General Description

The directional studio microphone MKH 816 T is a transistorized RF condenser microphone. The DC voltage necessary lor operation IS led through the conductors 01the connecting cable (A-B powering according to the German standard DIN 45595).

Features:

. High directionality

. Low equivalent sound pressure level

. Rugged and extremely resistant to unlavourable climatic conditions

. High sensitivity

. All metal housing with black linish

Principle of high frequency circuit

The capsule 01 an RF condenser microphone presents, contrary 10 low Irequency circuits, a low impedance output. Instead 01 the high polarization voltage normally required, a high Irequency capsule needs only a high Irequency voltage 01 about 10 volts, wh ich is produced bya built-in low noise oscillator (8 MHz). The low capsule impedance leads to a high performance reliability 01the mlcropho- nes.

Powering and connection

Sennheiser electronic introduced A-B powering, which was then standardized in DIN 45595. As with dynamic microphones, only two wires are required to connect the microphone when this powering system is being used. The operating current is led along the same wires as the audio Irequency signal, so that the circuitry in the microphone does not have to be connected to earth. Because 01this earth Iree technique the highest possible values 01 immunity

lrom noise or disturbance are achieved. For suitable powering units see "Accessories".

The connection 01Senn heiser condenser microphones and dynamic microphones as weil is carried out using the prlnciple 01 voltage matching. The advantages 01this system are that neither impedance variations 01the microphone output nor 01the amplilier input exercise a noticeable inlluence on the total Irequency

response. The source impedance 01the Senn heiser condenser microphones with A-B powering is so low (approx. 8 Q at 1000 Hz) that an amplilier input with an impedance 01at least 400 Q will be suitable. This is usual in the majority 01 cases. However, il the Input impedance is smaller than 400 Q, a reslstor 01 appropriate

value should be placed in se ries with the microphone so that it

"sees" aleast 400 Q. The voltage division caused by this series resistor must 01 course be consldered. The same method can be

used when a highter output impedance 01the microphone is demanded. In this case again aseries resistor can be used to provide correct matching.

Senn heiser condenser microphones produce relatively large output voltages; these can be up to 1 volt with maximum sound pressure levels. This has the advantage that even with long cables induced interference signals can be disregarded. Also the internat noise produced by the microphone does not contribute to the total noise level. The microphones are litted with high Irequency lilters, wh ich ensure that no high Irequency signals Irom the microphone can allect the external circuitry, and also that the microphone Itsell is protected Irom high Irequency disturbance. It is, therelore, not necessary, even under the most dillicult conditions, to take special precautions such as double screening 01 the cables or the provision 01 high Irequency lilters.

Sennheiser condenser microphones are polarised according to DIN standard, i. e. when apressure signal strikes the capsule Irom the lront pin 2 01the XLR-connector goes positive with relerence to pin 3.

Connection to balanced microphone inputs

In this case the microphone is simply connected to the input 01 an

amplilier via a battery adapter MZA 16 TU or the power supply unit MZN 14 TU.

Connection to unbalanced microphone inputs

For connection to unbalanced inputs contact 3 01the connecting cable between the powering unit and microphone has to be

grounded. Note: With the MZN 16 TU this is only possible after the unit has been modilied.

Apart Irom cases where the microphone is being used lor proles- slonal studio purposes, thls IS not critical, as the large output voltage 01the mlcrophone combined with its low output impedance provides a large signal to noise ratio. Care should be taken, however, that no multiple ground circults are lormed when the microphones are mounted on tripods etc.

Connection to microphone inputs with high sensitivity

IIthe unit being used has a very high Input sensitivlty, i. e. when it IS normally intended lor use with dynamic microphones, it can be necessary to reduce the output voltage Irom the microphone by means 01 a voltage divider, which should be built into the micro- phone cable at the mlcrophone input. By this means the large signal on the microphone cable is maintained up to Just belore the micro- phone Input, which results in a Increased signal to noise ratio.

Connection to mixers and sound recording equipment with powering facilities

IIan approprlate voltage source is available the condenser micro- phone can be powered directly. The voltage should be 12 volts

:t 2 volt. It should be so stabilised and filtered, that the unweighted noise voltage is less than 5 {lV and that the weighted noise compo- nents are less than 2 {lv. The current consumption 01the micro- phone is approximately 6 mA. According to the DIN standard the resistors should be 2 x 180 Q. This means that the voltage drop across the resistors is appprox. 2 V (Iig. 3).

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