I found this item in the Neumann forum archive, from 2003, submitted by Jeffrey Rassier:
"I record 80-90 live orchestral and chamber concert events per year. I've experimented with EVERY possible stereo micing technique and have recently developed one of the most spacially and tonally pleasing combinations: mixing a spaced pair of KM183 and an ORTF pair of KM184. The omni KM183 yield a wonderfully spacious environment, while the KM184 add detailed placement of sources. (If you grasp the concept of the space created by this technique, ponder this: companding the cardiod pair...the space subtley opens and closes proportionate to the dynamic levels.)

The Neumann response was this:
"Dear Mr. Rassier, interesting technique, indeed.
The late Mr. Straus, head of Tonmeister institute in Detmold, developed the Straus Paket ('package'). Omni (KM83)and cardioid (KM84) sitting on top of each other, so he could mix the omni and cardioid pairs separately. Yielding a variable subcardioid setup. Similar approach but not identical to your technique, especially regarding the compression.
Best regards, Martin Schneider Neumann Mic. Development

While I don't think the Original Poster was referring to a 'Straus Packet' since his mic pairs were arrayed conventionally (spaced omni and ORTF) rather than above/below..the companding part intrigues me.....

It's the OP's contention that companding the cardioid pair might allow for spatial image variation proportional to the dynamic levels. I'd imagine a situation where a dynamic passage follows a quieter one, and on exceeding a threshold the omni pair might 'close down' so that the image becomes tighter, while in a quiet passage the omnis might open up to give more spaciousness ? Am I reading it right ? Would the 2 pairs be linked via a sidechain compressor scenario, so that (proportional to volume or dynamics) one might predominate over the other. In theory it sounds intriguing, but I'm having trouble visualizing it's implementation. My instinct would be to compand the omni pair,rather than the cardioid, as in dynamic passages they could contribute to 'wooliness', while their 'air' is precisely what you'd crave during the quieter parts. There's going to be the suspicion and reluctance of the "must ride faders manually" crowd to something like this, which smacks of gating or threshold dependent automation, but I'd like to hear of how it might be implemented on an experimental basis. The Waves C1 compander could be called into service here, among others...?

Quote studer58:

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It's the OP's contention that companding the cardioid pair might allow for spatial image variation proportional to the dynamic levels.

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Companding is the wrong word -- it's been corrupted in translation! Companding implies compression followed by expansion, but that's not what he's doing here.

What he is suggesting is compressing the ORTF pair such that when the orchestra plays loudly the ORTF pair is reduced in level -- slightly -- allowing the spaced omni pair to take on a more dominant role, and thus provide a slightly more ambient hall acoustic.

It's something that classical balancers sometimes do manually for the same reason (but without the inevitable compressor side-effects). Following the score and anticipating when to dip the ORTF pair is usually more subtle tha waiting for a compresor to realise it's getting loud and reacting to it.

Quote:

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I'd imagine a situation where a dynamic passage follows a quieter one, and on exceeding a threshold the omni pair might 'close down' so that the image becomes tighter, while in a quiet passage the omnis might open up to give more spaciousness ?

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The omni pair isn't being compressed at all, so it s level isn't affected or adjusted at all -- it's the ORTF pair that is being compressed -- and only by a relatively small amount sufficient to shift the balance slightly towards the spaced omni pair. Probably no more than 3-4dB maximum gain reduction.

Quote:

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My instinct would be to compand the omni pair,rather than the cardioid, as in dynamic passages they could contribute to 'wooliness', while their 'air' is precisely what you'd crave during the quieter parts.

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No, it's the other way around. The room is excited when the orchestra plays louder and by holding the ORTF array back a little with a compressor that is emphasised with the proportionately greater omni signal. This gives a greater sense of scale and grandeur during the fortes, while the more intimate passages are still heard in detail and clarity.

hugh

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Technical Editor, Sound On Sound

Like the idea. Will try that later this month. But not (ahem!) with Neumans!

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PA stuff on FB

Thanks for that detailed reply Hugh, I'm still trying to get my head around what happens when music gets loud...and quiet... in a typical concert hall. At the quiet end the ear can strain to pick out detail over the ambience (hence spot mics on woodwinds and harps for example), and I can imagine the 'sharper' detail exposure of the typical ORTF pair comes in handy. At the forte end the detail, even from omni mics, becomes magnified thanks to Fletcher-Munson, as if the omnis had mutated into zoom-in shotgun mics, but the ambience can now become cloudy and indistinct, if standing waves are excited ? So isn't this the time when you might want to dip the omnis down in level relative to a cardioid pair ? Excuse me if I'm getting all this back to front..and I agree fully with your point about not trusting the blend process to a compressor or automation !

Quote studer58:

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So isn't this the time when you might want to dip the omnis down in level relative to a cardioid pair ? Excuse me if I'm getting all this back to front..and I agree fully with your point about not trusting the blend process to a compressor or automation !

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Experiment as you wish. I was clarifying what the quote was referring to and the techniques I have seen, used and taught.

Hugh

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Technical Editor, Sound On Sound

This post has been made on more forums than there are stars in the sky, and the responses here really show the depth of this forum, and more specifically HR. (We all knew that, but concrete demonstrations from time to time never fail to impress!)

I've appreciated this discussion as it has presented some ideas I've not entertained before. Even some various obvious ideas, but they were only obvious after being illuminated here. But more interesting are many other creative ideas this discussion has generated. I didn't know this was a technique, and didn't know of its precedence. The ideas will find their way into my work, I'm sure, even though they will no doubt be differently employed.

The Strauss packet, of course, is well known.

So, thanks to Studer, Guy, and Hugh.