A quick search of Google finds ...
http://mixonline.co…
http://www.soundons…

and a really excellent 2MB PDF here:
http://www.wesdoole…

In general, I find this method way too woofly and undefined for anything but big orchestral forces, where its main application was/is.

Here is a link:

http://www.acmi.net…

IMO this technique is often mis-applied for small sources like choir, piano trio, etc, where other techniques work better. DPA coyly suggests that 4003/4006 with 40mm balls will emulate the M50. You should also note that this ruthlessly exposes less-than-great string sections.

Some have noted that the Schoeps M222/MK2H with balls also come very close.

The "traditional" dimensions are 1m arms (so L & R are 2m apart) with the C mic extending 1m. The Decca engineers did not fail to modify spacing, angles, etc. as conditions demanded.

If you want an off-the-shelf tree, go here:

http://www.wesdoole…

a Google search will bring up fascinating reading!

Rich

I am in a situation where Decca Tree is kind of the implied "only solution"

It's a small chamber orchestra (35 pieces give or take) playing in a church. I don't have the luxury of mounting the mics behind the conductor, but the conductor can move back a little.

So, I'll be putting a stand just in front of him (just enough that the baton doesn't meet the stand plus a little wiggle room.) I'll put a 3 foot stereo bar on top the stand with the MG M296s as the main L/R. Then, I'll set up a Schoeps CMC6 ext/MK2Sg 3 feet in front of and centered with the main stand.

The hall is plenty reverberant, so going any distance from the orchestra will spell trouble with balance, even using directional mics (this has been a problem in the past with this group in this venue.)

I'm afraid of the results, but truthfully, I'm more afraid of the results from the alternative methods too, so it's a "lesser of two evils" situation.

We'll see what happens...

J.