Sennheiser sm 1008 User Manual

Contents

1. Description ......................

1.1 Model SK 1008 Mikroport

Transmitter. . . . . . . . . . . .. . . . ..

1.2 Microphones ,...

1.3 Model EM 1008 Mikroport

Receiver. . . . .. . . . . . . . . . . . .. . . .

1.4 Antennae . . . . . . ..

2. Preparing equipment for operation. .

2.1 Transmitter..................

2.2 Microphones ,...

2.3 Receiver....................

2.4 Antennae ,.

3. Operation........................

3.1 Transmitter..................

3.2 Microphones ,,""""""""

3.3 Receiver......................

4. Special situations................

4.1 Diversity reception ............

4.2 License ,...........

4.3 Special frequencies .. . . . ... . .

4.4 Tape recording .. . . . . . . . .. . . .

4.5 Powering external units

4.6 2-mV output..................

4.7 Hum prevention ,...

Page

1 2 3 4 5

5 5 6 6

6 6 7 7 7 7 7 7

1. Description

The SM 1008 wireless microphone system consists of a battery-operated miniature transmitter, Model SK 1008, which can be equipped with several different special microphones, and the battery/AC operated receiver, Model EM 1008, which can be operated with a variety of special antennae.

1.1 Model SK 1008 Mikroport

transmitter

The Mikroport transmitter is operated trom an ordinary 9 V battery, Standard units are designed for two trequencies:

36.7 and 37.1 MHz. Two plug-in micro- phones and seven special microphones, which can be connected via short leads, permit adaptation to even unusual appli- cations. A plug-in antenna is supplied with the transmitter.

1.2 Microphones

Two different plug-in microphones may be combined with the Mikroport trans- mitter into a single unit. The combi-

nation, which is no larger than a con- ventional microphone, may be either held in the hand or used as a lavalier

microphone via its built-in cord. Model MD 1008 plug-in microphone,

which has spherical characteristics, is preferable whenever it is essential to obtain minimum sensitivity to vibration, and where (especially during interviews) several persons speak into the micro- phone trom different directions. However,

where there is a high ambient noise level, reverberation, or the possibility of acoustic feedback, it is recommended that the Model MD 4008 plug-in micro- phone, which has super-cardioid di- rectional characteristics be employed. Where concealment of the transmitter is desired, special microphones may still be used, connected to the micro-

phone socket of the SK 1008 transmitter via a short cable. The most frequently used unit, for this application, is the Model MD 214/1 Lavalier suspension microphone. Besides double internal suspension, which renders this micro- phone strongly resistant to noises pro- duced by friction, the Model MD 214/1 dynamic lavalier microphone has a shaped frequency response that com- pensates for attenuation of high fre- quencies caused by the chin of the speaker. The Model 405-T directional hand-held microphone can be used in a similar fashion, worn in an outside pocket, permitting the transmitter to be switched on and off by means of the

switch on the microphone. The Model MM 61-2 fountain pen microphone and Model MM 24-2 lapel microphone are even more inconspicuous, although their transmission quality is not as

good as that of the previously-mentioned

microphones. Where stringent quality requirements exist, the Mikroport trans- mitter mayaiso be connected to one of our transistorized capacitor micro- phones via a special cable, Model

KAM-1. Either the Model MKH 104 with spherical characteristics, the Model

MKH 404 with cardioid characteristics, or the Model MKH 804 with ultra-direc-

tional characteristics, may be employed.

Power for these microphones is obtained from the Mikroport transmitter battery.

1.3 Model EM 1008 Mikroport

receiver

This newly-developed receiver may be operated from the AC line or from a standard 9 V battery. The two antenna inputs (60-ohm and 240-ohm impedance) permit the use of different antennae. Transmitter field strength can be con- tinuously monitored with its built-in meter. A balanced, ungrounded 1.55 V audio output provides a signal at less than 2 % distortion. The signal may also be monitored simultaneously at

variable volume via a built-in loud- speaker.

1.4 Antennae The wire antenna supplied with the

Mikroport receiver does not have the same reception performance as the Model TA 203 telescopic accessory antenna. If a Ionger antenna cable is required, e. g., for diversity reception, (See Section 4.1), it is recommended

that a tuned 240-ohm dipole be prepa-

red with a cable of suitable length.

2. Preparing the equipment for operation

Reliable operation of the entire system can only be guaranteed by the manu- facturer if all parts used are original Sennheiser products and no unautho- rized alterations have been made by a third party.

If the micraphone spacing is increased, (or if loudness is reduced), It will be necessary to advance the control ac- cordingly, while loud speech or a reduction in micraphone distance re- quires a lower setting. To facilitate precise matching of the system in studio operation, it should be mentioned that correct adjustment of the sensitivity

control is obtained when the audio output of the receiver supplies + 6 db

(1.55 volts) at modulation peaks.

3.2 Microphones

In operating the micraphones it is merely necessary to note that directional types (MD 4008, MD 405-T, MKH 404 and MKH 804) should be pointed directly at the sound source wherever possible, since they are naturally less sensitive to sounds coming from the

sides and rear.

3.3 Receiver Model EM 1008

The receiver is switched on by depress- ing the "ON" push button. In battery operation it is also advisable to depress the "battery test" push button to deter- mine whether the pointer deflects weil into the red range of the indicating instrument, indicating an adequate re-

serve. The same channel selected on the transmitter must be selected by

depressing the appropriate button on the receiver. As soon as the transmitter

is switched on, the instrument will show the fjeld strength. The pointer must

come to rest in the green section, indicating an adequate signal is present. Advancing the volume control enables the transmitted signal to be monitored by means of the built-in loudspeaker.

This output signal is available for feeding amplifier or tape recorder sys- tems having a standard studio input level of 1.5 V (+ 6 db). To prevent noise being transmitted to the amplifiers or tape recorder systems when the transmitter is off, the 'squelch' control should be adjusted by turning it slowly clockwise, starting fram position 1, until the meter needle jumps into the blue

field. When the transmitter is switched on, the squelch relay will be activated

and the meter will show fjeld strength. When the automatic squelch feature is not required, the squelch contra I can be lett at position 1. In order to reliably check operation it is advisable to switch on the transmitter and walk over the entire transmission area while a second

person observes the field strength indi- cation. Excessively low antenna voltage, indicated by a pointer on the lett-hand side of the scale may be impraved by

reorienting the antenna.

4. Special situations

4.1 Diversity reception For particularly important applications,

where not even the slightest temporary reduction of transmission quality can be tolerated, it is possible for two or

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Dipole antenna construction

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as desired

Fig. 11

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