Royerlabs, the microphone manufacturer has released a recording tip series, and today i bring you the one about classical recording (really helpful if you are going to record small ensembles, or even a full symphonic orchestra)
In this series, you can find several miking techniques applied to an orchestral section, mic placement and samples to compare the different techniques, for example:
One of the most common miking techniques in the classical world, is the use of the Decca Tree as your main mic set up.
Decca Trees are often used when recording orchestras. Developed in the early 1950s by a team of engineers at Decca Records, this method involves using a spaced stereo pair of mics with an added center fill, usually placed over the conductor. The setup includes 3 omnidirectional microphones in a “T” pattern. The stem of the T faces the orchestra, and the left and right mics are placed about 6 feet apart. The third is placed 3 feet out and centered in front. To mix, the side mics are panned hard left and right, and the output of the centre mic is then sent to both left and right channels.
The technique traditionally uses three omnidirectional microphones, traditionally of the Neumann M-50 (or the M-150, the modern version) , to record in stereo. Variations have been performed using a coincident pair, in X-Y, Mid/Side (M/S), or Blumlein positioning, in place of the center microphone (check this link about Neumann mics history)
As a supporting material, in this article you have pictures from recording sessions to better understand how and where the mics should be placed.
As my own advice, CHECK YOUR PHASE CORRELATION between the Decca Tree and your spot mics before press the REC button.
A excelent way to do this, is measure the delay (time,in miliseconds) between the sound captured by the spot mic and by the decca tree, and delay the signal from the spot mics according to the time difference…….and always FOLLOW YOUR EARS!