Stereo microphone techniques compared

A stereo pair of microphones can encode direction in two ways: level differences between the channels, and time differences caused by the spacing between the capsules.

Coincident pairs: level differences

Two directional capsules at the same point, angled apart. Sources off-centre are louder in one capsule.

• XY: usually two cardioids at 90° to 120°. Mono-compatible and precise.
• Blumlein: two figure-8 microphones at 90°. Captures the room naturally; includes sound from behind.
• Mid/Side (MS): one forward-facing capsule (mid) plus a sideways figure-8 (side). Left = M + S, right = M − S. The stereo width can be adjusted after recording.

Spaced pairs: time differences

• AB: two omnidirectional microphones, typically 40 cm to a few metres apart. Wide, spacious and deep bass, but with less precise localisation and a weaker mono sum.

Near-coincident pairs: both

Angled capsules with a small spacing combine level and time differences:

Recording angle

The recording angle is the width of the sound field that is reproduced between the loudspeakers. Sources outside it appear hard-panned. Wider spacing and wider capsule angles make it narrower, so the ensemble must be placed accordingly. The stereo recording angle tool estimates this for any setup.

Which to choose?

Use coincident pairs when mono compatibility and precision matter, spaced omnis for a spacious, natural room feel, and near-coincident pairs as a compromise.

Draft: written by an AI assistant, awaiting technical review.