Hello Rubio,

you are right, KM184 (cardioid) is the typical Neumann choice for live acoustic guitar amplification. Used for example by the Los Angeles Guitar Quartet. Then, for applications where you need a lot of amplification and thus increased feedback rejection, one would take the KM185 (hypercardioid). But most musicians seem to do well with the cardioid.

Best regards,
Martin Schneider / Neumann Mic. Development