The Digital Microphone Interfaces in general
Equipment that supports the AES 42 standard can process the output signals of Solution-D microphones directly. In all other cases, the DMI-2 portable or DMI-8 digital microphone interface is used. The DMIs convert the AES 42 data format supplied by the microphone into an AES/EBU signal.
The Interface is operated via the Neumann RCS remote control software, which is installed on a desktop or laptop computer. The computer is connected to the DMI via a USB port and a USB to RS 485 interface converter. If a large number of microphones is used, several DMI-8's can be cascaded. In this case, each digital microphone interface can be addressed individually.
In addition to a word clock input and output, the DMIs also have an internal word clock generator. If no master word clock signal (e.g. from a mixing console) is present at the input, the DMI internal word clock is used automatically to synchronize the microphone channels, and the signal is switched to the word clock output.
External commands such as "On Air" (red light) can be controlled via a 9-pin user port.
The DMI-8, an eight-channel version of the digital microphone interface is considerably simplifying the setup for multichannel applications.
In addition to the proven functions of the two-channel DMI-2:
- AES 42 to EBU conversion
- Powering, remote control and synchronization of the microphones without a sample rate converter (AES42, mode2)
- Automatic word clock or AES 11 synchronization
- All sample rates, from 44.1 kHz to 192 kHz
- Complete control and storage of the settings via Mac or PC
The DMI-8 also offers the following features:
- The capability of cascading up to 128 channels
- Level meter and gain setting on the front panel, operable even without a computer
- D-sub 25 outputs with Tascam® and Yamaha® pin assignments
- Optical ADAT® interface
- Open architecture for later connection to other multi-channel interfaces and audio networks, such as EtherSound® and MADI
The DMI-8 offers several possibilities for easy integration into audio networks. The ES100 (DMI-8) module permits integration into EtherSound networks.
Explanation Mode 2:
The DMI performs a frequency/phase comparison between the word clock signal recovered from the mic signal, and the word clock of the DMI. From the phase deviation thus determined, the DMI calculates a control signal which is transmitted via the remote control data stream to the mic, where it controls the frequency of the internal quartz oscillator.
Description of inputs and outputs
AES/EBU OUTPUT Routing
- The AES/EBU signal includes 2 audio channels
- The distribution of the audio data of adjacent mono microphone channels between the audio channels of the corresponding AES/EBU output signal is as follows:
Digital stereo microphones are supported at odd numbered AES42 microphone inputs only. In this case the audio data of the microphone are routed to the left and right channels of the corresponding AES/EBU output.
1)All values are for non-condensing humidity.