Topic: New Digital Mics

[TNJazz]

I believe it needs its own "power supply" box, which just happens to connect via AES42.  I would imagine there's digital output on it and that they somehow can be combined to a stereo digital signal.

[BWolf]

well on the neumann page it says something like "planned arrays of up to 8 mics", but i don't know if that needs their little controller box or not...

either way, just thought it was a cool thing to check out.  in no way could i afford these, just thought it was an interesting topic. 

[Nick's Picks]

well...these were built w/the studio in mind.  and i'm sure its no trouble plugging in several AES feeds into one box...like any multi-track digital recorder.

[stirinthesauce]

 

I'll take a stab 

You have made your rounds with most all of the gear accessible today for our needs.  But not once, multiple trips around the block 

But this is not a bad thing per se, so a big +T

Oh.
now I see.

 

[Nick's Picks]

what can i say.  i'm bad w/my finances.

what would be REALLY bad would be if I kept all that stuff.  one something comes in....something goes out. 

sometimes I have to liquidate the rig for one reason or another.  its fun to rebuild.

[stirinthesauce]

what can i say.  i'm bad w/my finances.

what would be REALLY bad would be if I kept all that stuff.  one something comes in....something goes out. 

sometimes I have to liquidate the rig for one reason or another.  its fun to rebuild.

Agreed.  

[DSatz]

The problem with AES-42, as I understand it, is that each microphone has its own internal sample clock. Thus there is no simple way to synchronize a pair of digital microphones (or any larger grouping) to a common clock signal. As a result, the only practical way to record from more than one microphone at a time is to resample the bitstream from each microphone asynchronously, at the point where the signals are combined, to a common clock signal.

It's my understanding that this strategy was chosen so that for "normal," everyday lengths of cable, existing balanced analog microphone cables could be used with these digital microphones. (For lengths beyond a few hundred feet, special lower-capacitance digital cable is recommended.) That's all very nice and friendly, but it complicates the requirements for the recording equipment in an unfortunate way. Thus there aren't many options to choose from yet.

Neumann does have battery power supplies available for their KM-D microphones, but I don't think that you can combine the signals of two such microphones for stereo recording without using their AC-powered controller to reclock them.

[BWolf]

after reading the thing on the neumann website, it says you can synchronize these with the power and control box, or run them asynchronously. 

from the site:
The AES 42 standard describes two modes of synchronizing the microphone with the receiver (e.g. a mixing console or DMI-2 digital microphone interface):

Mode 1: The microphone operates asynchronously, using the sampling rate of its internal quartz oscillator. In this case, a sample rate converter is required at the receiver. However, this mode of operation should be used only if mode 2 synchronization is not possible, since conventional sample rate converters will impair the signal quality, for instance in terms of dynamic range and latency time.

Mode 2: The microphone is synchronized with a master word clock, which can be either an external word clock or the internal word clock of the DMI-2. In this case, a frequency/phase comparison of the microphone signal with the master word clock is carried out in the AES 42 receiver (DMI-2). A control signal is then generated that is transmitted via the remote control data stream to the microphone, where it controls the frequency of the internal quartz oscillator.

[twatts (pants are so over-rated...)]

[head feels all spinny]
going back in for a reread......

Use this thing with an external Word Clock for 2 mic use:

DMI-2 digital microphone interface



T

[wbrisette]

there is nothing in our field recording realm, that I know of, that will allow for stereo recording wth a pair of these, short of a fully rigged laptop.
Is there an easy interface?
I don't know, and am not going to research it, because these are so far out of consideration.

ermm.... the Deva will. It can handle 8 digital inputs.

Wayne

[BWolf]

there is nothing in our field recording realm, that I know of, that will allow for stereo recording wth a pair of these, short of a fully rigged laptop.
Is there an easy interface?
I don't know, and am not going to research it, because these are so far out of consideration.

ermm.... the Deva will. It can handle 8 digital inputs.

Wayne

yeah, as long as something can send a clock to it, all the mics will synch.  possibly a 744T.  do the deva or 744t take AES digital inputs? 

for my knowledge, what does the AES cable look like?  is it a regular XLR on one side and a coax on the other?  or is it just a regular XLR cable?

[Nick's Picks]

regular xlr looking.  the cable impedance is different though.  110ohms

[gratefulphish]

You can pick up a stero pair of the Solution Ds on B & H for only $14,999, out the door, plus shipping. Windscreens are only $58.95. 

[Nick's Picks]

and then about that much to actually use them in the field.
who here has a hollywood budget I can envy?

[John Willett]

Quite a few questions in this thread to answer.

Price - the KM-D series *with* the DMI-2 control box is about the same price as the equivalent high quality analogue microphones (eg: that works out cheaper than the equivalent Sennheiser MKH 20).

ADC - The A to D converter is 28-bit and better resolution than analogue - the output is 24-bit to AES42.

Clocking - the mics are clocked by the DMI-2 interface which controls two mics. Several of these can be cross-linked to a single clock time up to 8-channels at the moment (software is being continuously updated and updates are downloadable from the Neumann website).

Writeup is HERE

I have used them in anger for nine solid days and have found them superb.  The built-in limiter prevents clipping and there are several switchable options including a compressor.

I have the omni heads and already have my name down for the flat-omni heads when they come out.

When future equipment incorporates AES42 inputs you won't need the DMI-2.

If I missed any questions please ask again and I'll do my best.

John