This type of microphone has a directional pattern between omni and cardioid. The basic idea in designing the CCM 21 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 in a useful manner. It has fuller and more extended low frequency response than a cardioid, with less proximity effect, while attenuating side- and rear-incident sound less than a cardioid.
The polar diagram shows the directivity of the CCM 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 CCM 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.