Microphone Polar Patterns

[SoundHound]

Do you look at the manufacture's polar patterns as well as their frequency response charts when you are comparing mics? A polar pattern is a graphical representation of the microphone's sensitivity by axis. Complete polar patterns will have overlapping graphs of many frequencies because mics will have different polar patterns varying with frequency.

At a glance you can see how a mic will sound when your actor talks into the side when the boom operator misses his cue or, when by design, he "sides" the mic to a, louder overlapping, actor to balance the level of a softer speaking actor he has put on axis.

Also note the jagged "phasey" uneven polar pattern of shotgun mics at the sides and rear. This is why they sound so strange inside and so nice outside. The reflections from interior walls are received by the shotgun's "interference rejection tube" and "phase" differently depending on frequency.

These reflections are virtually absent (not in a forest though) when there are no adjacent reflective surfaces and this accounts for the desireable "reach" too. Careful polar chart observation will show you where the mic is least sensitive. If you can orient that axis to the noise and the front of the mic to the actor you have maximized your, desired, signal and minimized your, undesired, noise.

Tip: If you point a Sennheiser MKH70 or Neumann KMR82 straight down to the ground from overhead to intercept the actor's voice you will "Tune Out" horizontally polarized (there's that word again) noise. Works just as well for "Lofer" mic placement (mic points up to the sky under the chin of the actor on closer shots).

But don't expect the Sennheiser MKH 815/816 to do this because the polar patter is different.

Want to identify a superior sounding interior mic with good reach. Study the smoothness (uniform pattern verses frequency) of your hypercardiod mic candiates. The smoothest polar pattern I have ever seen belongs the the Neumann KM105/KM185 hypercardoid capsule.

I was told by the microphone's designer at a visit to Neumann Berlin that their KK50 capsule had the best X/Y (matrix) performance of their entire line (and the KM105/KM185 are, by far, not their most expensive music recording mics). Note too that the Schoeps MK41 hypercardiod capsule is no slouch either.

Wonder about that newcomer Sennheiser shotgun the MKH8070? I haven't used it but for sure it will have excellent outdoors reach. But watch out because if your actor is just a bit off axis you are going to lose highs. Or use it for for a lispy actor and side the very tight pattern just a tiny bit. Bit don't expect a lush sound indoors.

Note too that the 8070's frequency response is virtually flat to 10Hz so you will be buying the $500 low cut accessory with the mic. The high end goes out almost flat 30Khz so by now you might get the idea that the 8070 wasn't designed for dialogue but could be pressed into that service. The MKH70 has a built in roll off switch and a high frequency boost switch usefull-when you use the, muffling, dead cat windscreen cover.

If you interested there's lots more since polar patterns describe fundamental characteristics of wave motion and work just the same for aerials too but at Radio Frequencies.

[jrd456]

Pointing a mic. straight down can cause more problems than it can resolve in practical usage.

J.D.

[studiomprd]

" Pointing a mic. straight down can cause more problems than it can resolve in practical usage. "

can, or may cause ??

either way, it depends!

--and, BTW, pointing the mic upwards may (or can) also have issues...

that, too, depends.

The microphone polar pattern most folks don't give enough credit to is the figure 8; besides as a side mic in M-S stereo, it is often a very useful pattern on its own.

[graham]

Hey Mike,

I read Crew's post a while back about live music, dialogue and a figure 8. If you could elaborate more on your post I'd appreciate it. What situations has it worked for you in.

[studiomprd]

The null of the figure 8 pattern (typically sides) is the best of all the mic patterns.

I've used them over live audiences (nulling SR).

Between 2 x actors in a vehicle..

sometimes nulling front/back can be a creative way to deal with a specific issue,

these mic's were extremely popular in radio situations, and also early TV.

just before the SM-58 came around, Shure had a terrific fig 8 ribbon mic that was a popular live vocal mic on stage

(max rejection at the sides, where the speakers were!)

[Chris Woodcock]

Between 2 x actors in a vehicle..

Where did you rig the mic?

[Jesper Magnusson]

Pointing a mic. straight down can cause more problems than it can resolve in practical usage.

J.D. - could you elaborate on this? Are you thinking about floor/ground reflections? I've boomed for a mixer who preferred the "straight down" approach, which I think is because it allows you to get very close and also minimizes changes in the background.

[studiomprd]

" it allows you to get very close "

typically a slight outward tilt, pointing towards the talent's breastbone can often get a touch closer...

but of course...

it depends

[rafaeldelauz]

I found this very smart and interesting. I just have a question. Why no setting up a cardioid mic on top that Figure 8 and have the option of recording a stereo image of the scene?

[studiomprd]

" Why no setting up a cardioid mic on top that Figure 8 and have the option of recording a stereo image of the scene? "

huh??

I did mention that these days, and in our typical uses, the fig 8 pattern is mostly used as the s mic in M-S, though typically, in recording production sound dialog, we are not usually in a position to know what the actual spatial relationships will be (ought to be) in the finished edited product.