WCSA

When choosing the right microphone array for a specific acoustic surround sound capture, the distance and angling between microphones and choice of microphone directionality must be considered.

For obtaining the desired enveloping sound character (and for enhancing the listening place to a sweet area instead of being a sweet spot) the five signals should be decorrelated, meaning placing the microphones at an adequate distance from each other. On the other hand, the signals may not be too different from each other, in this case the result will not be coherent.

For spaced arrays omnidirectional microphones are often preferred, especially due to their natural sound color and capability to blend direct signals with room timbre. Wide cardioids (also named half-omnis) have a slightly more directional quality giving more ambience control and improved front imaging and localization accuracy.

This tree was initiated by Geoff Martin and Jason Corey, summing a DPA omni and a DPA cardioid to create a wide cardioid characteristic. By focusing on preventing interchannel interference, the microphone pairs were spaced L-C 60 cm (24 in), R-C 60 cm (24 in), front-rear 60 cm (24 in) and LS-RS 30 cm (12 in). Rear mics were upwards aiming regular cardioids to capture height information.

DPA Microphones adapted this array to using five identical wide cardioid microphones (matched within a very narrow tolerance - ±1 dB on frequency response and sensitivity). Choosing five identical microphones instead of a microphone type blend naturally leads to authentic and uniform reproduction of all channels.

After intense listening evaluation and numerous practical try-outs in different recording applications from symphonic music, via modern jazz to PA/Live pop concert ambience recording, the adaptation tends to recommend a larger spacing, especially of the rear channels. This array creates an intense, dynamic and enveloping sound character.

The recommended distances are:

L-C 60-75 cm (24-30 in)
R-C 60-75 cm (24-30 in)
C-LR 20 cm (8 in)
Front-Rear: 150-200 cm (59-79 in)
LS-RS: 120-150 cm (47-59 in)

For wide ensembles (or large array to source distances), try expanding this array with two left/right omni outriggers to benefit from the pressure transducer's low frequency pick-up. These microphones are blended with L/R from the array in appropriate level, offering a beautiful coherent, precise and rich surround sound image.