what is figure-8 ambient sound sensitivity?

dumbangel · Post by **dumbangel** » Sun Oct 21, 2007 5:15 am

Omni is 100%

cardioid is 33%

hyper-cardioid is 25%

How about figure-8?

drumsound · Post by **drumsound** » Sun Oct 21, 2007 1:51 pm

I don't understand your figures.

Max · Post by **Max** » Sun Oct 21, 2007 2:10 pm

Are you talking about off-axis sensitivity? A figure of 8 mic should have 0% at 90 degrees to the mic's main pick up axis.

dumbangel · Post by **dumbangel** » Sun Oct 21, 2007 2:58 pm

Omni mics are sensitive to sounds coming from ALL the axises in space around them. (front, back, up, down, sides, etc?)

Cardioid mics are sensitive to sounds coming from only 33% of these axises, etc?

I don't know the ratio for figure-8.

philbo · Post by **philbo** » Sun Oct 21, 2007 5:55 pm

Putting a single number on mic pickup polar patterns is sort of useless.

It's like asking how bright the sun will shine tomorrow - - in the shadow of the moon, it'll be 0% bright, but in the plains, it'll be 40%t. And if you are on Mercury, it'll be 97%.

The pickup of a mic, from a given direction, for a given frequency, will be described by it's polar plot diagram. This is a 3D array of values. One dimension is the angle of the sound source relative to the mic diaphragm. Another is the frequency. The 3rd is the amount of attenuation that sound will have, relative to a 1 KHz sound whose source is directly in front of the diaphragm.

The reason polar plots are used is because a single number is just not sufficient to describe the pickup pattern. Dumbing it down to a single number is misleading at best.
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dumbangel · Post by **dumbangel** » Mon Oct 22, 2007 2:32 am

I read these figures in this thread:

http://messageboard.tapeop.com/viewtopi ... ensitivity

don't know where the author found them originally. Or did he make them up?

red cross · Post by **red cross** » Mon Oct 22, 2007 5:22 am

dumbangel wrote:Omni mics are sensitive to sounds coming from ALL the axises in space around them. (front, back, up, down, sides, etc?)

Cardioid mics are sensitive to sounds coming from only 33% of these axises, etc?

I don't know the ratio for figure-8.

Not really as simple as that. Omnis tend to be directional at high frequencies too. And the off axis freq response of various cardiod microphones has quite a large effect on how they sound as well.

joel hamilton · Post by **joel hamilton** » Mon Oct 22, 2007 8:01 pm

I am 100% sure this will never help me make a better record.

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what is figure-8 ambient sound sensitivity?

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