Cardioid microphones as measurement microphones

[bambi]

Hi,

What do you think about measuring reflecting sound energy from a surface using directional microphones (measurements in free-field)?
It would be interesting measuring reflecting sound energy arriving at the microphone from a limited angle range. This angle range would be defined by the directionality of the microphone (small diaphragm mics and shot guns with cardioid polar responses).

The only problem I see is that the directivity of microphone is not going to be equal at all frequencies, and therefore the reflected sound energy measured by the microphone will not depend only on the reflected sound field but on the directivity variation of the microphone.

Anyone has done acoustical measurements with non-omnidirectional mics?? does anyone know a directional microphone with a reasonable constant polar response from 500 Hz to 6k ?

Thanks for your comments!

 

[Bruce B]

As you stated, the polar patterns of a cardioid mic have different freq. responses.

For a cheap mic to use for acoustical analysis, there is the Dayton Audio EMM-6

For a much better alternative, there is the Earthworks M30 or M50