Topic: Running Schoeps CMD-2U(Digital Microphone Bodies)w/Sound Devices 788T

[jobseek2001]

Gunnar: thanks!! 

[John Willett]

This whole digital microphone thing confuses the hell out of me...

Do they have a built in A/D converter? Do they have selectable bit-depth/frequencies? Sorry... I haven't even begun to read about them. Advantages?

The ADC is right behind the capsule (in the case of the Neumann) - so there is only the capsule and a fet before the ADC - in the Neumann it's a patented 28-bit device.

The AES42 standard sets the bit-rate at 24-bits - the sample rate is selectable (44.1 - 192kHz) and can be free-running (mode 1) or clocked (mode 2).

The 788T is mode 1 operation and clocks the microphones by going through a sample-rate converter.

Schoeps (at the moment) are mode 1 only.

The Neumann and Sennheiser digital mics are mode 2, but can also be operated mode 1.

If you use a controller like the Neumann DMI-2, DMI-8 or RME 842 then these can be clocked from an external clock.

In my own case, running a pair of Neumann KM-D series through the DMI-2 into a Nagra VI recorder - I can set the Nagra as master (as it has an extremely accurate clock) and feed the clock-out from the Nagra into the DMI-2 so the microphones are clocked by the recorder.

Using digital microphones you don't need an analogue pre-amp, so you save money here.  Also, as the ADC is perfectly matched to the microphone, you get the best digital transfer - you don't have to back-off your mic. pre. to allow a safety headroom and you don't have to back-off your ADC to allow for headroom as everything is done perfectly in the mic..  The result is you actually get a better s/n ratio at the end.

In addition, as the signal is run digitally from the mic. you don't get any HF loss or RF pick-up affecting the signal as you do in analogue circuits - and you don't have all this analogue stuff in the way which adds noise and distortion as you go along.

I have been using digital mics since December '06 and am very happy - I now have a pair of KM-D with both 183 and 131 heads and an MZD 8000 for my Sennheiser MKH 8000 series mics.

I hope this helps.

[F.O.Bean]

John, thanks for explaining things in the ENGLISH LANGUAGE and not in tech talk I now understand this whole concept a little better now, so thanks

[blee421]

  I ordered the Schoeps Digital Bodies today(CMD 2Uxt) through Sonicsense.Mojan is always great to work with and was super helpful.So I come to find out that you have to specify to Schoeps what bit depth and sample rate you need, then they modify it.I chose 24/96.If you want to change them,you have to mail them back to a Schoeps dealer to be modded again.

  I messed with the 788T breakout cable today and here is how it works.Each digital body puts out 2 channels.I will be using 4 digital bodies(4 mics).I am using the(DE-15/aes/xlr)connector channels -1,2  -3,4  -5,6  -7,8.Channels 1,3,5,7 will be switched to digital since you only need one channel off each body.That leaves channels 2,4,6,8(which all have internal pre's) open to use with microphones or line in from an external preamp or SBD feed.The 788T clocks all 8 channels internally.

 I also ordered a new 32 GB CF card.I hope it is enough to do 8 channels.

[John Willett]

So I come to find out that you have to specify to Schoeps what bit depth and sample rate you need, then they modify it.I chose 24/96.If you want to change them,you have to mail them back to a Schoeps dealer to be modded again.

With the Neumann and Sennheiser AES42 mics you can do all this yourself through the RCS software that comes with the DMI-2.  You can change and lock in the sample rate as many times as you want.  Once you have done this you can use the mic. directly into the SD 788T.

I did check - but with the Schoeps they have to go back to them to do the basic settings if you want them changed.

You never know, Schoeps may come out with a Mode-2 unit in the future instead of the Mode-1 they have now.

[JasonSobel]

I also ordered a new 32 GB CF card.I hope it is enough to do 8 channels.

8 channels of 24/96 is approximately 8 GB/hour, or about 4 hours of record time on a 32GB CF card.
or were talking about the speed of the card???  will it be fast enough to record that much data continously.... only one way to find out.

[F.O.Bean]

I also ordered a new 32 GB CF card.I hope it is enough to do 8 channels.

8 channels of 24/96 is approximately 8 GB/hour, or about 4 hours of record time on a 32GB CF card.
or were talking about the speed of the card???  will it be fast enough to record that much data continously.... only one way to find out.

IU'm intrigued to know if it can keep up to. I bought a 233x RiData 32GB CF Card before Hampton. Wonder if it would be fast enough? Newegg only charged me like 90/shipped for it.

How fast is your 32GB CF Card Brian?

[boojum]

So I come to find out that you have to specify to Schoeps what bit depth and sample rate you need, then they modify it.I chose 24/96.If you want to change them,you have to mail them back to a Schoeps dealer to be modded again.

With the Neumann and Sennheiser AES42 mics you can do all this yourself through the RCS software that comes with the DMI-2.  You can change and lock in the sample rate as many times as you want.  Once you have done this you can use the mic. directly into the SD 788T.

I did check - but with the Schoeps they have to go back to them to do the basic settings if you want them changed.

You never know, Schoeps may come out with a Mode-2 unit in the future instead of the Mode-1 they have now.

John, you have a knack of turning discussions about microphones into advertisements for Sennheiser/Neumann and it happens so often as in this hijacked thread, that I sometimes wonder if you work for them.  You would tell us if you worked for Sennheiser/Neumann, wouldn't you?  I mean you wouldn't just hang around here like a disinterested and objective hobbiest if Sennheiser/Neumann were paying you, would you?       

[notlance]

My experiance is that CF speed does not make much difference; just about all of them are fast enough.  Specifically, here is what I posted on the Team 7xx thread:

Concerning Compact Flash cards for the 788T, SD says "We recommend the use of UDMA x300 CF cards for 8+ track recording."
 
Well I just bought this Kingston 32GB CF and it's not a UDMA card and it's rated for only 133x

http://www.newegg.com/Product/Product.aspx?Item=N82E16820134901

Nevertheless, I was interested to see if it fast enough to record at high sample rates.  Recording 8 channels of 24/96 kHz works out to 2.2 MB/s.  Running a speed test on the Kingston  CF resulted in a rate of 4.9 MB/s; fast enough in theory.  I recorded about 3.5 hours of 8 channel 24/96 without a hitch, so it seems fast enough in practice also.

I've never tried a CF card that was too slow to work on either a 702 or a 788T.

[ghellquist]

John, you have a knack of turning discussions about microphones into advertisements for Sennheiser/Neumann and it happens so often as in this hijacked thread, that I sometimes wonder if you work for them.  You would tell us if you worked for Sennheiser/Neumann, wouldn't you?  I mean you wouldn't just hang around here like a disinterested and objective hobbiest if Sennheiser/Neumann were paying you, would you?       

I should let John talk for himself, but I have to chime in here.

I have over the last few years interacted a lot with John. And yes he is employed by Sennheiser in UK (which owns Neumann) which he never keeps as any secret. In this forum though he is not talking as any official representative of the company and should not sign as such.

I am also totally convinced that he talks about what he personally really thinks and likes about the products ha personally owns and uses in his work outside of Sennheiser -- he is a well respected recording engineer with quite a few commercial CD releases.

Gunnar
Just to be clear, personally I am employed by a Swedish insurance company as business controller.

[blee421]

John's threads here have been very helpful here.I am interested in all digital microphones and how it will work with the 788T.Thanks John!

[boojum]

John, you have a knack of turning discussions about microphones into advertisements for Sennheiser/Neumann and it happens so often as in this hijacked thread, that I sometimes wonder if you work for them.  You would tell us if you worked for Sennheiser/Neumann, wouldn't you?  I mean you wouldn't just hang around here like a disinterested and objective hobbiest if Sennheiser/Neumann were paying you, would you?       

I should let John talk for himself, but I have to chime in here.

I have over the last few years interacted a lot with John. And yes he is employed by Sennheiser in UK (which owns Neumann) which he never keeps as any secret. In this forum though he is not talking as any official representative of the company and should not sign as such.

I am also totally convinced that he talks about what he personally really thinks and likes about the products ha personally owns and uses in his work outside of Sennheiser -- he is a well respected recording engineer with quite a few commercial CD releases.

Gunnar
Just to be clear, personally I am employed by a Swedish insurance company as business controller.

Gunnar, many on this board are affiliated with companies or products pertinent to this hobby.  Crhis Church, Nick with his cables, Busman, DSatz with his peripheral association with Schoeps, GuySonic and so on.  They make their associations known either by advertising or comment.  And while you and some others may be aware of John's being an employee of Sennheiser not all on this board are.  And for that reason they could be misled into thinking that the fluffing of Sennheiser in a thread about Schoeps and SD was accidental.

It is especially unfortunate that John, himself, is reticent on this.  I am sure has has reason to remain silent.

[Brian Skalinder]

It is especially unfortunate that John, himself, is reticent on this.  I am sure has has reason to remain silent.

The silence may not be related to the issue you raise.  It could simply be that he hasn't made his way back to this thread.

[blee421]

Oh yeah.The CF card speed is 30 MB/second?I dont't know if that is fast or not.

[F.O.Bean]

Oh yeah.The CF card speed is 30 MB/second?I dont't know if that is fast or not.

Are you SURE? That seems RIDICULOUSLY HIGH Most cards do between 4-6/MBs. My 233x RiData 32GB CF Card does like 4.6-5.6 MB/s or so. My 150x 8GB RiData Pro does like 4.0 MB/s or so.