INTRODUCTION

This is not intended as a review, as Hugh Robjohns has already done an excellent review of the KM 184-D in the March 2007 issue of SOS HERE. Also, as Sennheiser UK pay my salary, you will obviously think any review as biased.

However – here I am taking off my Sennheiser/Neumann hat and putting on my Circle Sound Services hat to say why I invested my own money in a pair of KM 183-D omnis and a DMI-2 interface and will describe the start of an ongoing recording project using them. So I am sticking to facts and a description of how I used them.

I went over to Neumann, Berlin in November 2006 to be shown the new range and initially was thinking – digital microphones, great, but…..

However, I was forgetting about all the headroom that you have to allow for with analogue microphones. Headroom in the microphone pre-amplifier (and the additional noise in the analogue circuit) and the headroom you have to allow in the D/A converter. These two added together mean there is about a 25dB reduction in the s/n ratio – so, a 130dB dynamic range gets reduced, in effect, to only 105dB. That was point #1 that started me sitting up and listening.

The A/D in the Solution-D series (including the KM-D) is a patented Neumann true 28-bit conversion that gets the full dynamic range of the microphone – this is outputted as a 24-bit signal in the AES42 format. The interface controls the microphones and outputs the signal as standard AES3. Details of all this – AES42, Stephan Peus’s paper on digital microphones and product brochures can all be downloaded in pdf format from the Neumann website HERE.

Once the signal is in the digital domain in the microphone you can adjust the level, add compression, pre-attenuation, etc., even switch the microphone's power light on and off or change the brightness. This is all controlled by the Neumann RCS software included with the DMI-2 (see channel strip below).



And there is a lot more you can do in the digital domain in the microphone. Most important (and convincing point #2 for me) is the inclusion of an integral digital limiter that prevents overload. On a test with a microphone with this disabled, is was very clear how effective this limiter is. No distortion at all, it just does not get any louder. Great for transients that would normally distort the recording and require a re-take – now it’s just perfect.

Those are the main reasons why I immediately put my own money on the table and bought my own pair and I have also put my name on the top of the list for the new KK 131-D flat-omni (nearfield) capsules when they come out.



THE PROJECT

I have been asked to record a series of CDs for the pianist, Richard Meyrick. I have recorded Richard many times over the years, normally with Sennheiser MKH 20 omnis – but this time I also used the new Neumann KM 183-D digital microphones.

The project is sponsored by The Man Group and Blüther pianos, so our hands were not tied to get a good sound.

The recording venue was The Menuhin Hall in the Yehudi Menuhin School in Stoke d’Abernon. This is a superb building with a great sound. It is totally isolated from outside noise with a perfect cable route to the Green Room where we set up the recording equipment.

AES42 signals can only travel about 10-metres along normal microphone cable, so I went along to Canford Audio and got them to make me some custom cables (yes, I know - I’m lazy and I am not proficient with lead-free solder yet) made with proper balanced AES digital audio cable, terminated with the new Neutrik EMC XLR connectors. AES42 at 24/96 can travel about 200-metres along these cables, so distance was not a problem.

As this was my first outing with the KM-D series, I did a parallel recording with a pair of MKH 20s (as you can see in the picture).



The microphones were set up as shown in the photo (just click on the picture to get the large version). As the KM 183-D is a diffuse-field omni, it has a lift in the upper frequency range. But I had the microphones only about a couple of metres from the piano. Anyone who has seen a polar-pattern of an omni microphone knows how the high frequencies are attenuated off-axis due to the physical size of the microphone. We started with having the 183-Ds at about 45°, but found this was still a bit too bright; so we turned them through 90° and had them vertical. At this position the frequency response was ruler flat and the piano sounded great (the MKH 20s didn’t need turning as they have a flat response head on).

The KM 183-Ds were connected to the DMI-2 interface which locked them to the same clock time. They were set to a 96kHz sample rate and a digital gain of 25dB was applied (in practice this was fine as the absolute maximum peak ended up being about -1.6dBFS – I ended up not needing the limiter at all). I did not apply any compression at all.

The output of the DMI-2 was fed to an AES splitter which outputted to a Fostex FR-2 for the main recording at 24/96. The second output went to an Audio Design ProBox 10 sample rate converter which down-converted to 16/44.1 to record a DAT safety copy on my old Fostex D-10. The MKH 20s went to an Audio Design DMA2 24/96 mic. pre. and into a second FR-2 (kindly loaned by SCV London for the event).

Monitoring was via a Grace m902, Sennheiser HD 650 headphones and Klein + Hummel O110 active monitors (as shown in the picture – again, click the image to get the large version). Talkback was via my custom unit (made by myself many years ago) which also controlled the red lights. I also used “The Box” for stereo soundstage imaging.



The first recording session was five consecutive days just before Christmas ’06. The sessions went extremely well and the microphones behaved flawlessly. We were delighted with the results.

The KM-D microphones are so quiet that we had no background noise “clue” when we were playing back. We kept thinking something was wrong, as every time we started to play back a take we couldn’t hear anything – until the music started. They are quiet!

The sound of the microphones is the sound of the capsules with nothing added and nothing taken away. Once we had tamed the top end by angling the microphones correctly, everything was wonderful.

Earlier this year, we spent a weekend with Samplitude9 on the PC, editing most of the sessions and the pianist and sponsors are absolutely delighted with the results.

We are going back for the next sessions just before Easter and a CD of Chopin music should be released mid year. We have more sessions booked and further CDs will follow later.

Yes – we chose the KM 183-D microphones for the release (not that the MKH 20s weren’t good – but this combination was the best one in this situation).

I don’t spend my own money lightly - probably something to do with my Scottish great-grandmother - and I certainly have no regrets in doing it this time.

In fact the KM 183-Ds work out quite cheap – including the interface, a pair works out at about the same price as any top class omni (slightly cheaper than a pair of MKH 20s) – but when you factor in that you don’t need a mic. pre. or A/D, or even a limiter / compressor...

And - when the mixer and DAW manufacturers come out with AES42 inputs on their equipment, you won't even need the interface.

All in all, I'm delighted and plan to add to the system as it is expanded over the next year or two.

(Forget I work for Sennheiser - this is my own money I'm spending here - no regrets, it's great)

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John - Sound-Link ProAudio
President - Federation Internationale des Chasseurs de Sons

Edited by Forum Admin (17/09/07 10:44 AM)

Many thanks for that John - honest & unbiased - just like the recording turned out, eh?

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Don't ya jus luvvit?

Concise & easy to understand review JW.

Thank you.

Quote TImellis:

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Many thanks for that John - honest & unbiased - just like the recording turned out, eh?

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As honest and unbiased as I can be.

I liked the mics. I bought them with my own money - and this is how I used them.

Yes, it can be difficult when you are writing about something made by your employer - but if something excites me I want to talk about it; and this excited me so much I spent my own money on it.

For a review that is totally unbiased, read Hugh Robjohn's review - you can take this how you wish.

But I liked them so much I bought them myself.

What I write I believe - negatives I may leave out, but I honestly couldn't find any with these, other than the brightness which I fixed with moving them to the best angle for the best results.

And my customer is so delighted that he plans on a 3,000 production run for the CDs.

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John - Sound-Link ProAudio
President - Federation Internationale des Chasseurs de Sons

Very nice, John.

I'm looking forward to hearing them

I hope you didn't think there was any sarcasm intended, John, in my post - not at all - you came across totally honest and unbiased.
Would you predict a time when digital microphones become the norm?

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Don't ya jus luvvit?

Quote TImellis:

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Would you predict a time when digital microphones become the norm?

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They'll never become the norm, but they will become a lot more common and even mainstream -- particularly in classical and serious music recording circles.

But there will always be those who want to stay with analogue because they like the limitations of that technology. They like the distortions, and they like the 'black art' of choosing mic preamps and A-D converters to create a particular sonic character. You can't do that with digital mics, and especially not with mics as good as Neumann's Solution D series.

John is quite right, the KM-D mics are stunning in every way, and I am sorely tempted to buy a pair myself but can't really justify it at present.

Hugh

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Technical Editor, Sound On Sound

John,

I amended the IMG tags to show the missing 2 pictures so have removed this secondary post.

ian G


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John - Sound-Link ProAudio
President - Federation Internationale des Chasseurs de Sons

Edited by Forum Admin (17/09/07 10:46 AM)

As a postscript - I have now ordered a pair of the new KK 131 flat-omni heads for the KM-D system.

And if anyone else is using the Neumann Digital microphone systems there are firmware upgrades downloadable from the Neumann website.

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John - Sound-Link ProAudio
President - Federation Internationale des Chasseurs de Sons

Quote John Willett:

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What I write I believe - negatives I may leave out, but I honestly couldn't find any with these, other than the brightness which I fixed with moving them to the best angle for the best results.

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That makes it sound like the mics are inappropriately bright, which isn't the case. These particular capsuels were intended for diffuse field use adn John didn't want to use them that way, hence having to correct the response by turning them off axis. Neumann has now produced direct field omni capsules, and the fact that the off axis response of the originals sounded so good is a testament to the quality of the original capsule design.

I have to agree with John that the KM-Ds are phenomenally good mics, and althoguh they appear expensive initially, when you look at all the other things you no longer need in your recording chain, they are actually very good value for money. It was only the whispers of a similar Sennheiser system in the near future that disuaded me from buying the KM-Ds myself.

hugh

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Technical Editor, Sound On Sound

Quote John Willett:

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It seems the hosting site has removed a couple of the pictures I posted on the original review.

As I can't edit it to reallocate them - I am posting the missing pictures here:-

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Nice to see your stereo image box gets a regular outing John...

Quote RegressiveRock:

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Nice to see your stereo image box gets a regular outing John...

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Of course, it's excellent and invaluable - I use it on every recording session.

If you want one you get it from Mike Ballance (yes, that *is* his real name) at Tabor Audio.



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John - Sound-Link ProAudio
President - Federation Internationale des Chasseurs de Sons

The Box is quite useful once you've learned how to interpret it (which doesn't take that long), and it is quite cost effective.... but the DK-Technologies meters are soooo much better and do sooo much more..
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...but they do cost a lot more!

hugh

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Technical Editor, Sound On Sound

Quote Hugh Robjohns:

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The Box is quite useful once you've learned how to interpret it (which doesn't take that long), and it is quite cost effective.... but the DK-Technologies meters are soooo much better and do sooo much more..

....but they do cost a lot more!

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I agree - but five times more (and more).

I would have got one if they were cheaper.

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John - Sound-Link ProAudio
President - Federation Internationale des Chasseurs de Sons

Quote John Willett:

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I agree - but five times more (and more).

I would have got one if they were cheaper.

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But it does do five times as much!

Bargraph level meters with selectable scales and true peak indicators

Spectrum analysis as 1/3 octave RTA or FFT

Phase meter

Lissajous display (goniometer)

Surround jellyfish/starfish displays (on the surround meters)

Routing matrix

test tone generator

Loudness measuring

Digital fault logging

Stereo Downmixing (for surround version)

...and more.

It's not that I'm a huge fan or anything..... and other metering systems are available

And yes, I did have a BOX too, but I stopped using it and gave it to a friend.

hugh

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Technical Editor, Sound On Sound

I agree and it's on my list - after the MKH 8020 stereo set, the MKH 8040 stereo set, the Nagra VI, the U87 Anniversary Edition and a new PC.

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John - Sound-Link ProAudio
President - Federation Internationale des Chasseurs de Sons

Quote John Willett:

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and a new PC.

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Stop using them then, and use a proper recording system

Quote Aural Reject:

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Stop using them then, and use a proper recording system

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I *do* use a proper recording system.

You don't think I actually use a PC for recording do you? It's far too risky - I don't trust them that far.

But I *do* use a PC for editing and mastering. If it all goes tits up I still have all the original material.

Using a PC for recording - madness - whatever next.

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John - Sound-Link ProAudio
President - Federation Internationale des Chasseurs de Sons

Trust no-one

Editing? You mean they don't get it right first time like my lot?

Quote John Willett:

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You don't think I actually use a PC for recording do you? It's far too risky - I don't trust them that far.

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I use a PC for recording -- with the SADiE LRX2 -- but for critical stuff (what isn't?) I back up with a Genex 8500 Hard disk recorder. But to be fair, I've not had any problems so far recording to the laptop with an external drive....

hugh

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Technical Editor, Sound On Sound

As I promised - I *have* now bought the KK131 flat-omni heads for the KM-D.

I have yet to use them in anger, but will probably use them more than the 183 once the current recording project is finished.

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John - Sound-Link ProAudio
President - Federation Internationale des Chasseurs de Sons

Update:-

Neumann have released, in the last week, updated RCS software (v2.0.1) that complies with the latest version of the AES42 standard.

They have also released new software updates for the DMI-2 controller and the KM-D series, D-01 and TLM 103-D microphones.

I have just updated all my kit.

The new software also works with the new Sennheiser MZD 8000 digital module that is due for release very soon.

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John - Sound-Link ProAudio
President - Federation Internationale des Chasseurs de Sons

Update -

Neumann have recently launched more new capsules for the KM-D series including the KK 133 omni with ball head and KK 120 fig-8.

They have also launched the new KM-A analogue version of the KM-D so the same capsules can be used AES42 digital or conventional analogue.

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John - Sound-Link ProAudio
President - Federation Internationale des Chasseurs de Sons

The Neumann KM 185 D has come out and it's not bad. It has a good A/D converter. I used it to record a pianist at a piano teaching academy

Edited by Hugh Robjohns (31/01/11 05:35 PM)

Why not? We are using them in for our guitar lessons london

Edited by Hugh Robjohns (31/01/11 05:35 PM)

Quote icarus22:

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The Neumann KM 185 D has come out and it's not bad. It has a good A/D converter. I used it to record a pianist at a piano teaching academy (PTL - piano teachers london )

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The KM 185-D was one of the original 3 launched in 2006.

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John - Sound-Link ProAudio
President - Federation Internationale des Chasseurs de Sons

Neumann have just launched the DMI-2Portable - it's a slimline DC powered version of the mains DMI-2.

Shipping starts next week (week 3, 2011) and I have already ordered a pair of them so I can record four AES42 digital mics at the same time into my Nagra VI.

For some reason it's not on the Neumann website yet; but I'll post the link when it's up.

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John - Sound-Link ProAudio
President - Federation Internationale des Chasseurs de Sons

Quote John Willett:

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Quote icarus22:

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The Neumann KM 185 D has come out and it's not bad. It has a good A/D converter. I used it to record a pianist at a piano teaching academy (PTL - piano teachers london )

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The KM 185-D was one of the original 3 launched in 2006.

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That post, and the other one above yours are both spam.

Paul

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Paul

The new DMI-2 Portable interface is out now and I received a couple the other day to go with my Nagra VI.

It's not on any website yet, so this is a scan of the Owners Manual pictures:-





I will upload pictures of my own units as soon as I ave them all sorted and cabled up to the Nagra VI.

The DMI-2 Portable is DC powered and I can power two of them from my Nagra VI to record up to four digital mics at once.

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John - Sound-Link ProAudio
President - Federation Internationale des Chasseurs de Sons

Not sure why the image of the DMI-2Portable does not show in the above post.

The picture is HERE.

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John - Sound-Link ProAudio
President - Federation Internationale des Chasseurs de Sons

Quote John Willett:

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I will upload pictures of my own units as soon as I have them all sorted and cabled up to the Nagra VI.

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OK - here it is.

My Nagra VI and the two DMI-2Portable interfaces for recording four digital mics. at once:



The two DMI-2Portable are both powered from the Nagra VI and they are clocked from the very accurate word clock in the Nagra VI.


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John - Sound-Link ProAudio
President - Federation Internationale des Chasseurs de Sons

The DMI-2Portable is now on the Neumann website HERE.









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John - Sound-Link ProAudio
President - Federation Internationale des Chasseurs de Sons

For more information on digital microphones...

I have written two AES papers on the subject.

The first was presented at the 130th AES convention in London in May 2011 and the second (a bit longer) at the UK AES Conference "The Ins and Outs of Audio" in June 2011.

Both these papers list all the products for AES42 digital microphones from all manufacturers to give a complete picture.

You can download the PDFs from the links below:-

Digital Microphones - What's it all about?

Digital Microphones - AES42 and all that

I trust these will be useful in explaining AES42 digital microphones.

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John - Sound-Link ProAudio
President - Federation Internationale des Chasseurs de Sons