Topic: Spaced Omnis - two schools of thought?

[Gutbucket]

my split cards:  https://archive.org/details/dbt2005-03-02-dpa4023.flac16

Thanks Colin. That exemplifies the weird extenuating circumstance of recording live, PA-amplified music from out in the audience.  From the source description: "mics split 24' and hung from each side of the balcony approximately 4' from each stack".  Less extreme yet conceptually similar to the hypothetical situation described previously of one PA speaker and microphone a mile apart from the other, yet still producing a predominantly monophonic signal from the PA, common to both channels.

[voltronic]

A late entry to this thread: If the two schools of thought are ~3 feet apart vs. ~1 foot apart, times have really changed since I was first learning to record--and very much for the better as far as I'm concerned. If you look in any American-published books or magazine articles from the 1960s and 1970s about stereo recording, the "cookbook" formulas were exactly two: One was to take the width of the stage, divide it by three, and place one omni at each of the lines of demarcation (i.e. 1/3 of the way across and 2/3 of the way across respectively). The other was to take a pair of cardioids and aim them with the heads pointing together at a 90 degree angle.

Both are perfectly dreadful ways of recording music in stereo, and are especially regrettable because with the same microphones, it's so easy to do so, so much better.

But as far as omnis are concerned, the more enlightened texts used to distinguish between "small" A/B, which was the European style, and "large" A/B, which was the American style as described above. Back then, the two encampments were pretty much mutually exclusive. I remember being shocked that small A/B could work at all, since the 1/3 and 2/3 rule was the only approach I ever saw used; with anything less than that wide spacing, I couldn't believe that you would "get enough separation" for stereo until I tried it myself.

By the way, this included the fellow who used to record our high school band back in those years, as well as the Honors and State bands in Western Pennsylvania that I played in: a Mr. Renner who ran a company called "Century Recording Service" just on the other side of the Ohio state line. He later became better known as the chief engineer for Telarc Records. While I'm happy for the Grammy awards he received (and the fact that he mainly used Schoeps microphones), most of the famous Telarc orchestral recordings have a huge hole-in-the-middle problem; once it's pointed out, you can't not hear it.

My earliest education in recording technique also was having the classic 3-to-1 rule hammered in to me.  I think it works quite well for PA applications, such as when arranging hanging area mics for a choir or theater production.  The "small" A/B is something I've only come across recently, and it was so against everything I was taught that I also was shocked at how good it could sound.

Out here in Eastern Pennsylvania we still have the same problem with professional companies who are recording our marching band and drum corps shows.  Almost every single time, I see X/Y center, with omni flanks that are 30 yards (not feet) apart.  They cover the field I guess, but the imaging is, for lack of a better term, strange.  Here's an example of this, with my favorite pro corps:

https://www.youtube.com/watch?v=4xsVnAEwVDE

At 2:58 you can see the center array, but the mics appear to be pointing straight ahead?!?!

 

[Gutbucket]

^That's quite a production.

Hard to tell from the low res video, but looks like a near spaced pair in the center, and maybe a near-spaced pair at all three mic locations.  Regardless, I definitely hear a hole in the middle.

3-to-1 rule is different than the old 1/3-2/3's positions across the front of the orchestra omni spacing thing.  But that doesn't keep it from being commonly suggested as appropriate for a stereo pair of omnis, even though it's impossible to apply to stereo mic'ing.  Two microphones cannot be three units of measure apart from each other and one unit of measure from the same source, it's simply geometrically impossible.  I never thought about it before, but I suppose the 1:3 and 1/3-2/3 numbers are similar enough that the two 'rules' become prone to confusion even though they address entirely different things.


I've blathered way too much about arcane technical aspects in previous posts.  Pressed for a quick & dirty guideline of omni spacing for stereo recording, I'd probably sum up my approach like this:

1'-2' with some sort of baffle (disk, sphere, head, or body) in between
3' with nothing in between
6' with another mic in between
More than 6' may work well in certain situations common to TS for the reasons mentioned, but gets riskier, is probably at the point of diminishing returns, and may become harder to setup in a practical sense.

[voltronic]

I posted the results of the 1-meter omnis on the press box here: http://taperssection.com/index.php?topic=169429.msg2158669#msg2158669