Neumann.Berlin DMI-8 - Handbuch (Seite 8)

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phones connected to the DMI-8 must always be
operated in synchronous mode, whether or not
sample rate converters are used in the subse-
quent signal chain. The transmission of none syn-
chronized microphone signals is not supported by
the DMI-8.
Ensure correct fastening of the connectors when
connecting the cables.
Lay the cables in such a way that they do not pres-
ent a tripping hazard.
Updating of fi rmware
The fi rmware in the DMI-8 and in the Neumann
microphones is updatable. Updates can be per-
formed without opening the equipment, via the
RCS control software (see the RCS Operating
Manual).
6. Technical data
Permissible atmospheric conditions 1)
Operating temperature .....................0 °C to +45 °C
Storage temperature .....................–20 °C to +70 °C
Relative humidity ................... max. 90 % at +20 °C
AES42 inputs: ......................................... 8x XLR3F ,
Audio data in accordance with
AES/EBU (AES3) data format,
Digital phantom power (DPP)
Remote control data
Phantom power (DPP): ...................................+10 V,
max. 250 mA per channel,
short-circuit proof
Remote control data: ......................... Pulses (+2 V),
superimposed on the
phantom power,
approx. 750 bits/s or 9,600 bits/s
(depending on the microphone)
Outputs: ..............................2x SUB-D 25, AES/EBU
(AES3) data format,
Yamaha and Tascam pinout,
1x Toslink, ADAT format up to 48 kHz,
1x RJ 45, GN format up to 192 kHz,
incl. power-out pin: approx. +15 VDC, max.1 A,
short-circuit-proof
Sampling rates supported: ....................44.1 / 48 /
88.2 / 96 kHz /
176.4 / 192 kHz
1) All values are for non-condensing humidity.
Microphone
synchronization: ............................AES42 – Mode 2
(synchronous mode)
Microphone clock control via PLL
DMI-8
Synchronization ....... automatically to an external
word clock or AES11 signal,
if present, otherwise the internal
word clock generator is activated.
Word clock (or AES11) input ............................BNC
Vin ....................................... >100 mV at 75 ohms
Word clock (or AES11) output ...........................BNC
Vout .................= Vin (external synchronization)
Vout ..............................approx. 1.5 V at 75 ohms
(internal word clock generator)
Internal word clock
generator: ...................... 44.1 / 48 / 88.2 / 96 kHz/
176.4 / 192 kHz
Accuracy ±25 ppm
Indicators:............... Power, Ext Word Clock, Valid,
Level (microphone)
Control elements: .......................8x Channel Select
GAIN +/–
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.
RS 485 with additional
power-out pin (approx. +11.3 V,
max. 500 mA)
Device address (ID): ........... 0 to 15, adjustable via
coding switch on the back
of the device
User port: .............................................9-pin sub-D,
1 switch function per channel
(Mute and/or Light 1/
Light 2 selectable)
Power supply: .................90 V to 240 V; 50/60 Hz
Power consumption: .....................................<55 VA
Dimensions: ...........(W x H x D) 483 x 88 x 210 mm
Weight: ..............................................approx. 2.8 kg
7. Additional information
7.1 AES42
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 defi ned 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
(+2 V pulses).
The data format of the digital audio signal trans-
mitted from the microphone complies with the
AES/EBU (AES3) standard. The user bits defi ned in
this standard are intended for the transmission of
various types of information. The AES42 standard
defi nes the signifi cance of these user bits with re-
gard to digital microphones. In the DMI-8, 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 AES42 input and an
AES/EBU output.
7.2 XLR cables
The length of cable that can be used from a digital
Neumann microphone to the DMI-8 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 48 kHz, high-quality “analog” XLR 3
cable (e.g. the Neumann IC 3 cable) can be used.
For greater cable lengths, the use of AES/EBU
cables (110 ohms) is required. If AES/EBU cables
are used, the following cable lengths are typi-
cal: Up to 300 m for sampling rates of 44.1 kHz
or 48 kHz; up to 200 m for sampling rates of
88.2 kHz or 96 kHz; and up to 100 m for sampling
rates of 176.4 kHz or 192 kHz.
Attention: If a long cable is used to connect the
microphone and the DMI-8, the DC resistance of
the cable used must not exceed a specifi ed maxi-
mum value, since 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 re-
turn line.
The length of cable that can be used from the
DMI-8 to subsequent equipment (e.g. a digital
mixing console) is substantially dependent upon
the technical features of the subsequent equip-
ment. Thus no specifi c statements can be made
concerning the cable length. In case of doubt,
the use of AES/EBU cables (110 ohms) is recom-
mended.
7.3 Operation without the RCS control software
All of the settings which are in eff ect when the
DMI-8 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-8 later, after the DMI-8 has
already been switched on.
When the RCS control software is started, the con-
fi gurations stored there for all of the microphone
channels are compared with the settings stored in
the DMI-8. If diff erences are detected, a menu is
displayed that asks which confi guration is to be
used (see the RCS Operating Manual).
7.4 Synchronization
The AES42 standard describes the following two
modes for synchronizing the microphone with the
receiver (e.g. a mixing console or the DMI-8 Digi-
tal Microphone Interface).
Mode 1: The microphone operates asynchronous-
ly, using the sampling rate of its internal quartz
oscillator. In this case, a sample rate converter is
required at the receiver. It should be noted that
sample rate converters can impair the signal qual-
ity in terms of dynamic range and enlarge the la-
tency time.
Attention: This mode is not supported by the
DMI-8
Mode 2: The microphone is synchronized by the
DMI-8. In this case, the DMI-8 performs a frequen-
cy/phase comparison between the word clock