Condensor mic polar patterns

[sparqee]

I'm confused about the mic orientation implied by polar pattern charts. In this chart it's pretty clear:



The direction of greatest rejection is the bottom of this hand held mic (i.e. where the cable would plug into the mic). But from discussions concerning figure 8 mics it seems that it's polar pattern is relative to the top of the mic (i.e. the circle in the middle of the below polar pattern represents the top of a figure 8 mic).



I think I'm answering my own question but please point out if I'm wrong. In order to understand one of these polar pattern charts you have to be aware of the direction that the mic capsule points. Yes? Handheld dynamics usually have a membrane that faces the top of the mic while condensers usually have membranes that face out of the side of the mic casing. So the polar patterns are relative to that orientation yes?

So, if this polar pattern chart shows you the rejection characteristics relative to the top of the mic, what are the rejection characteristics relative to the side of the mic? In otherwords: what are the rejection characteristics of the bottom (i.e. where you plug the cord in) of a figure 8 mic? Is it better to point the null point (of the side of the mic) towards the noise I don't want or is it better to point the bottom of the mic towards the noise I don't want?

- Sparqee

p.s. I do not currently own a figure 8 mic so I cannot experiment but I am preparing for a session where I plan to use two such mics to achieve a certain amount of separation between a singer and her guitar (i.e. recording her voice and her guitar simultaneously). I would like to be as educated as possible before going in. I have information on how to arrange the mics but I'm hoping for some clarification on this question concerning polar patterns.

[.tom]

the charts are always in reference to the diaphram. so, using a "side address" condenser in fig 8 position the pickup pattern is very focused and narrow in front and 180 degrees behind it also.

[sparqee]

So would the two image below be correct? I'm attempting to illustrate the polar pattern for the same mic viewed from both a top & side elevation.





Thanks,

- Sparqee

[richiebee]

I've never given it much thought, so I hope I'm right with my theory. Diaphragms are generally round. So the polar pattern forms a 3 dimensional spherical shape around it. Therefore, your diagram would theoretically be correct. However, microphone housing has to have an effect on response. The question is does the manufacturer compensate for it... in other words, can a perfect omni response exist? I have to admit, I don't know the answer to that! I've always thought and positioned microphones on the front/back/sides relationship. Not top/bottom.

[sparqee]

I think I have the concept now. I just needed to have enough of a visual understanding so that when I get on location and have the mics on hand I'm ready to start listening without too much thinking. You know how "thinking" can really slow you down.

Thanks,

- Sparqee

[.tom]

hahaha.. ya, u got it bro

[.tom]

also notice the slight roll off @30 degrees each direction -that's an important angle to memorize and "calculate" on the fly. then notice the "6db point" also because that's halving (hears 1/2 as well) the input coming from that "angle". this is found at the "60 degree" angles. useful to know if you want isolation from other sources.