Why must one use an omni mic instead of a cardioid mic? After all, we all own cardioid mics but it is uncommon to own an omni.

The most popular (2) mics ever invented are the Shure SM58 vocal mic & SM57 instrument mic. Both have cardioid pickup patterns.

Wouldn’t it be swell to just one one of those?

Let’s take a look.

INSERT RESPONSE OF SM58
INSERT RESPONSE OF SM57
INSERT RESPONSE OF OMNI X

What would happen if we used an SM57 (the flatter of the two Shure mics) to tune a sound system?

INSERT SIDE BY SIDE TRACES