Is there anything resembling a formula or basic guidelines for sizing
a Decca tree? I know the proportions (2X from left to right, 1.5X
from front to back) as described in the New Stereo Soundbook: but can
the overall scale be related to the size of the facility somehow?

The Decca tree was designed for orchestras. You can scale it down when working
with smaller ensembles. Some of the best imaging I've ever heard on Kronos was
a smaller Decca tree arrangement set up for a film scoring date they did at
Todd-AO. Direct to room ratio was incredible. I'm sure there's a point where
downscaling the tree makes it stop working & the imaging falls apart, & I
suspect that point will be determined by the pattern of the mics you use.

The standard proportions are
about right for M50s.

Bobby Fernandez, an ace Hollywood orchestral sound track engineer, told me he's
converted from M50s to Sennheiser MKH20s. Says he gets the same overall sound,
but with a lot less self-noise.

I don't think you can do Decca miking with something as omnidirectional
as the Schoeps. The whole point of the system is that it takes advantage
of the top end directionality of a large diaphragm omni.

It may be a stretch to even use the term "Decca tree" in this context, but I
heard a system using Coles 4038s in a tree arrangement for the PBS "Sessions"
series. Sounded very good, but was really a bit more like 3 spot mics over the
band than a coherent stereo image. Might have worked better if they were pulled
in together more, but this is a preset flown overhead arrangement, a sort of
one size fits all thing for that show.




Scott Fraser