This type of capsule has a directional pattern between omni and cardioid. The basic idea in designing this capsule was to combine the advantages of the cardioid with those of the omni. This results in a pickup pattern which blends the two sets of characteristics. It has fuller and more extended low-frequency response than a cardioid, with less proximity effect, while picking up more room sound than a cardioid. The polar diagram shows the directivity of the MK 21 to be only slightly dependent on frequency. This contrasts with omnidirectional capsules, whose directivity increases with rising frequency, and with cardioids (at least smaller ones), which tend to accentuate high frequencies that arrive at oblique angles. The MK 21's orientation is less critical than with a cardioid, since direct sound arriving on axis and reverberant or other sounds off axis are both reproduced accurately. This lack of coloration in the off-axis pickup produces a "warm" and natural sonic impression. The low directivity of this capsule type prevents it from generating large enough level differences for X/Y use, though M/S and near-coincident spacings are often successful. Together with the cardioid and supercardioid, this is one of the most preferred types among our capsules.
