Microphone Placement Calculator

Both apply the same multiple-microphone 3:1 guideline -- a second (or additional) microphone should sit at least three times its own distance-to-source away from the first mic to keep phase cancellation from combing the sound. Min Multi-Mic Spacing only shows a nonzero value when Number of Mics is more than one, since the guideline only applies once there's a second microphone whose relative phase could interfere with the first.

ORTF Spacing reports a fixed technique specification, not a calculation from your inputs -- the ORTF stereo miking method defines two cardioid microphone capsules 17 cm apart at a 110-degree angle as its standard configuration. Source Distance, Number of Mics, and Desired Stereo Width don't change this figure because it describes the physical mic-pair geometry the technique specifies, not something derived from your recording distance.

Spaced Pair Distance widens as Desired Stereo Width increases, because a wider target stereo image requires the two microphones to be physically farther apart relative to the sound source -- the calculator uses the tangent of half the requested angle scaled by Source Distance, so both a farther source and a wider desired image push the required mic spacing up. That relationship is only meaningful up to a point, though: as Desired Stereo Width climbs toward its 180-degree maximum, the tangent term grows without bound, so the result is capped at 20 ft -- a practical outer bound for even the widest professional spaced-pair setups (e.g. extended orchestral arrays), beyond which the raw trigonometry no longer describes a workable microphone position.

No -- it's a simplified inverse-square proxy based only on Source Distance, not a real measurement of your room's reverberation characteristics, and it isn't a percentage: it has no fixed 0-100 scale and can read well above 1 at short source distances. The actual point where direct and reverberant sound energy are equal (the "critical distance") depends on room volume, surface absorption, and reverberation time as well as source distance, none of which this calculator collects. Treat this output as a rough directional indicator, not a substitute for measuring or modeling your actual room.

X/Y Capsule Angle clamps your Desired Stereo Width into the 90-135 degree range conventionally used for coincident X/Y stereo pairs, since capsule angles outside that band are not typical for the X/Y technique. If you enter a Desired Stereo Width below 90 or above 135 degrees, X/Y Capsule Angle will show 90 or 135 respectively rather than your exact requested figure.