Microphones for B-format recording in Impulse Response Utility

A soundfield single point source microphone is ideal for B-format recordings. These microphones contain all the capsules you need to make a complete B-format reference recording in one pass. They also include hardware to send the separate axis streams to individual Impulse Response Utility tracks. You need to swivel the mic only once toward each speaker position, and the mic and processing hardware do the rest. If you do not have access to soundfield mics, Impulse Response Utility provides additional microphone options for B-format recording.

Capturing the W (sound pressure) signal requires an omnidirectional microphone. Capturing the X and Y axis signals requires a microphone with a figure-eight pattern that captures signal from the front and back of the mic. Therefore, with two figure-eight patterned microphones—one pointed directly at the speaker source (X) and another positioned perpendicularly (Y)—and an omnidirectional microphone for the sound pressure (W), you can record each speaker position in one pass. Be sure to arrange the microphones so that their capsules are as close as possible to each other. Ideally, you want to have a single, tight point of reference for each speaker position.

You need to swivel each of the figure-eight pattern microphones to each speaker position. The omnidirectional microphone does not need to be swiveled because it has a 360-degree capsule.

If you do not have three separate microphones, you can still create B-format impulse responses by recording each audio stream separately in Impulse Response Utility. All you need is a single microphone that allows you to switch between omnidirectional and figure-eight patterns. You will need to do a significant amount of pattern-switching and microphone swiveling, but it can be done.