#decca tree

204-1106 功學社音樂廳

Histoire du Tango

The Wave

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This is an example of what the same trumpet fanfare sounds like from three different microphone perspectives on MGM Scoring Stage. This is the natural sound of the room without any added reverberation. First comes the close microphones, then the Decca Tree and lastly the surround microphones. As you can hear all perspectives contain room reverberation of about 1 second. The main difference between them are instead the level of direct sound and early reflections from the instruments relative the indirect sound from the room.

The directional close microphones has a very narrow stereo image and contain a great deal of direct sound for obvious reasons, the sound is colored by the room but the tail is really only heard when the trumpets stop playing and is otherwise mostly drowned by the direct sound. The close perspective of each section is used to balance an usually otherwise unbalanced film orchestra or to bring out a section or soloist in the final mix for a more intimate sound.

The Decca Tree with its three omnidirectional microphones above the conductor podium has the widest stereo image while the trumpets still has a quite directional placement in it; as the setup consist of a left and right channel microphone separated by some distance and a center microphone that fills the "hole" in the middle of the image and add direction. This perspective contain a good balance between the direct and room sound and is the basis for the final mix.

The surround microphones are a regular omnidirectional A-B pair set up behind the Decca Tree but closer to the ceiling. As you hear in the example the big difference between the surround perspective and the Decca Tree is the "hole" in the middle of the wider stereo image, making it lose direction in the placement of the instruments, the sound of the trumpets seems to bounce between the right and left channel. Obviously the balance between direct and room sound favor the latter but there are still some direct sound as the surround microphones are indeed omnidirectional. However, notice that the higher frequencies of the instruments are attenuated due to the increased distance and being drowned out by the room. The surround perspective should not be brought up too much in the final mix, otherwise the stereo image phantom center will be lost, just enough to widen the image.

The final mix is a balance between these three perspectives and depends on the cue in question and the general sound of the soundtrack, anything between intimate to epic. Additional reverberation is also commonly added by digital reverb with a decay time between 1.5s and 2s that is either fed the full mix or just the surround microphones.

For fun, compare the score of Back to the Future (1985) to the score of The Avengers (2012) by the same composer and scoring mixer (Alan Silvestri and Dennis S. Sands) although at two different scoring stages (Warner Scoring Stage and Abbey Road Studio One). The first is an example of classic scoring stage only sound while the latter is an example of epic sound with added reverberation.

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