armans wrote:Is it not possible that cardioid patterns are more directional when it comes to high frequencies?
Some do get noticeably more directional at higher frequencies, some are reasonably consistent. But then, the same is true of many omnidirectional mics, too!
Having said that, most stay pretty consistent across the +/-60 degree angle. which is the important area pointing at the instrument!
It's an easy thing to test for, though: just make a constant hissing sound and rotate the mic slowly in front of your mouth over, say, 180 degrees, maintaining a constant distance between capsule and mouth, while listening for any significant level and response changes...
The Beyer MC930 is a nice mic for the money, and doesn't have a big presence peak -- but there is certainly a gentle lift about about 5kHz. the polar pattern does also narrow a little towards the HF, but that shouldn't affect the timbre of the guitar under normal circumstances.
But usually, 'harshness' of the form you describe is down to a combination of mic placement, the quality of the instrument, the nature of the playing, and the instrument's tuning.
Fundamentally, close miking results in each mic hearing the instrument in a way which isn't the norm, or even natural, for a human listener, so the sound can seem unnatural too....
In your case, you may find tweaking the tuning of the guitar helps, or spacing the mic a little further away...