The cardioid is the most popular type of directional microphone. It combines the highest level of audio quality with optimal suppression of rear-incident sound. SCHOEPS cardioids have a directional pattern that remains the same at all frequencies.
The range of applications for cardioids is unlimited. They are used for speech as well as for instruments and vocal soloists.

The MK 4 has been a reference microphone for years in a wide variety of recording situations.

Due to its transparent sound character and excellent attenuation of rear-incident sound, it reproduces sound sources very naturally. This has given the MK 4 a reputation as a universal "problem solver" even in difficult recording situations.

Its flat frequency response, and the constancy of its directional pattern for all frequencies, are the basis of the MK4’s sound quality. Even in the diffuse sound field its frequency response is flat, with a slight increase at 10 kHz compensating for high-frequency losses in the room.

Thus the sound image is transparent for direct-arriving sound, for sound arriving from the side, and for diffuse sound in the room (reverberation).

The MK 4 is a classic small-diaphragm microphone with all the advantages of this microphone type. Its frequency response and the consistency of its polar diagram from low to high frequencies are exemplary.

Like all SCHOEPS capsules, the MK 4 achieves its flat frequency response solely by its mechanical architecture, without any electronic filtering.

As a pressure gradient transducer, the MK 4 has a single diaphragm that is exposed to the sound from both the front and rear. The side sound inlets must therefore never be covered.

The “reach” (distance factor) of a classic cardioid such as the MK 4 is about 1.7 times that of an omnidirectional microphone. Thus even at greater distances from the sound source, direct sound can be obtained. The advantages of the MK 4 are shown especially when mixing several microphone signals - pickup of sound from the side is reduced in level but not subject to coloration.

At 90° the attenuation of the MK 4 is 6 dB, and at 180°, some 20 to 30 dB. Diffuse-incident sound is picked up 4.8 dB lower in level than front-arriving sound.