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Start the RCS program, or if necessary restart it, if the program was already on.

Attention: The DMI-2 must always be switched on before the RCS is started, so that the DMI-2 will be detected by the PC or Mac. While the RCS is op- erating, the cable connecting the computer to the USB 485 converter must not be disconnected, so as to prevent uncontrolled behavior of the com- puter. This requirement is due to the specifi cations of the USB interface.

Long modulation cables and multiple connections lead to a drop in the microphone supply voltage and to a deterioration of jitter behavior, particularly in the case of high sampling rates. Therefore, if possible, use continuous cable between the microphone and the DMI-2, and between the DMI-2 and subsequent equipment. For longer distances use AES/EBU cable exclusively (with an impedance level of 110 ohms).

Ensure that the microphone and all devices in the digital signal chain are synchronized. Microphones connected to the Neumann Digital Microphone Interface should always be operated in synchronous mode, whether or not sample rate converters are used in the subsequent signal chain. This permits very effective jitter suppression in the DMI (for hardware version 03 or above). In addition, the output of two microphone signals as an AES 3 stereo signal is possible only if the microphones are synchronized with one another.

When connecting cables, ensure that the connectors are locked correctly.

Run the cables in such a way that there is no risk of tripping over them.

Software updating

The software in the DMI-2 and in Neumann microphones is updatable. Future updates can be carried out without opening the device, via the RCS control software (see RCS Operating Manual).

6.Shutdown

Before switching off the microphones or disconnecting the cables, reduce the volume of connected equipment.

When disconnecting a cable, always pull only on the connector and not on the cable itself.

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7.Technical data

Permissible atmospheric conditions1)

Operating temperature .....................

0 °C to +45 °C

Storage temperature .....................

–20 °C to +70 °C

Relative humidity ...................

max. 90 % at +20 °C

Inputs:............

2 x XLR 3 F complying with AES 42,

 

Audio data in accordance with

 

AES/EBU (AES 3) data format,

 

 

Phantom power (DPP),

 

 

Remote control data

Phantom power

 

(DPP): .................

+10 V, max. 250 mA per channel,

 

 

short-circuit protected

Remote control data:.........................

Pulses (+2 V),

 

 

superimposed on the

 

 

phantom power,

 

 

approx. 750 bits/s

Outputs: ...............................

2 x XLR 3 M, AES/EBU

 

 

(AES 3) data format

Sampling rates supported:

........ 44.1 kHz, 48 kHz,

 

 

88.2 kHz, 96 kHz,

 

 

176.4 kHz*, 192 kHz*

Synchronization: ..........................

AES 42 – Mode 1

 

 

and Mode 2

Mode 1:..............................

Asynchronous mode,

 

microphone clock free-running

 

at selected word clock frequency;

 

a sample rate converter (SRC)

 

is required at the receiver

Mode 2: ...............................

Synchronous mode,

 

clock control effected via PLL.

 

If there is no external word clock,

 

the internal word clock generator

 

is automatically activated.

Word clock input ...............................................

BNC

Vin .......................................

>250 mV at 75 ohms

Word clock output .............................................

BNC

Vout .................................

approx. 2 V at 75 ohms

Internal word clock

 

generator:....................................

44.1 kHz, 48 kHz,

 

 

88.2 kHz, 96 kHz,

 

 

176.4 kHz*, 192 kHz2)

Accuracy:....................................................

±25 ppm

Indicators:......................................................

Power

 

Data Valid (microphone),

 

 

Sync Locked,

 

 

Ext Word Clock

1)All values are for non-condensing moisture.

2)only for DMI-2, hardware version 03 or above

Control bus: ....................................

2 x RJ-45 ports;

connection to computer USB port

 

via the Neumann USB 485

 

interface converter;

 

connected in parallel

 

for the purpose of cascading

Data format:.......................

RS 485 with additional

power-out pin (approx. +11.3 V)

Device address (ID):...........

0 to 15, adjustable via

 

coding switch on the back

 

of the device

User port: .............................................

9-pin sub-D,

3 switch functions per channel

Power supply: .................

90 V to 240 V; 50/60 Hz

Power consumption: ....................................

<30 VA

Dimensions: ..............

(W x H x D) 218 mm x 56 mm

 

x 163 mm

Weight: ..............................................

approx. 1.4 kg

8.Additional information

8.1AES 42

This standard is based upon the use of a 2-line balanced cable (AES/EBU cable; for short con- nections conventional analog cable can also be used). The power supply for digital microphones is defined as Digital Phantom Power (DPP) with +10 V and max. 250 mA. Modulation of the phan- tom voltage generates a remote control data stream which is transmitted to the microphone (as +2 V pulses).

The data format of the digital audio signal trans- mitted from the microphone complies with the AES/EBU (AES 3) standard. The user bits defined in this standard are intended for the transmission of various types of information. The AES 42 stan- dard defines the signifi cance of these user bits with regard to digital microphones. In the DMI-2, these data are separated from the audio signal and are transferred to the control bus, which serves as an interface for a computer or control device.

Fig. 3 shows a simple functional diagram of a mi- crophone interface with an AES 42 input and an AES/EBU output.

8.2XLR cables

The length of cable that can be used from a digital Neumann microphone to the DMI-2 is dependent upon the type of cable and upon the sampling rate

(word clock frequency) selected. For cable lengths of up to 100 m with a sampling rate of 44.1 kHz or

48kHz, high-quality “analog” XLR 3 cable (e.g. the IC 3 cable supplied by Neumann) can be used. For greater cable lengths, the use of AES/EBU ca- bles [110 ohms] is required. If AES/EBU cables are employed, the following cable lengths can typi- cally be used: Up to 300 m with a sampling rate of 44.1 kHz or 48 kHz; 200 m with a sampling rate of 88.2 kHz or 96 kHz; 100 m with a sampling rate of 176.4 kHz or 192 kHz.

Attention: If long cables are used to connect the microphone with the DMI-2, the DC resistance of the cables must not exceed a certain maximum value, since an excessive DC resistance would result in an impermissible voltage drop in the phantom power. The following formula applies:

Rc/2 + Rs < 18 ohms

Rc = DC resistance of the individual cable core,

Rs = DC resistance of the shield or the GND return line.

The length of cable that can be used from the DMI-2 to subsequent equipment (e.g. a digital mixing console) is substantially dependent upon the technical features of the subsequent equipment. Thus no specific statements can be made concerning the cable length. In case of doubt, the use of AES/EBU cables [110 ohms] is recommended.

8.3Operation without the RCS control software

All of the settings which are in effect when the DMI-2 is switched off are stored internally, and are automatically sent to the microphone when the equipment is switched on again. The most recent microphone settings are restored, without requiring a connection to the control device (PC or Mac).

The same procedure is followed if a microphone is connected to the DMI-2 later, after the DMI-2 has already been switched on.

When the RCS control software is started, the con- figurations stored there for all of the microphone channels are compared with the settings stored in the DMI-2. If differences are detected, a menu is displayed that asks which configuration is to be used (see RCS Operating Manual).

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