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Joe Scumbag · Posted - Sun Jul 13, 2003 11:21 am

Hi, I have a cardioid vs hypercardioid switch on my AKG C3000 mic. I learned that this has something to do with the width of the recorded field. In practice, when you want to record acoustic guitar or vocals, should the switch be on cardioid or hypercardioid?

djwayne · Location: USA

I haven't used that specific mic, but I would suggest experimenting with recording sound checks both ways, to see which sound you like best. This has worked for me in the past, and once I find a setting I like, I stick with it. Each mic, recording enviorment, instrument, has it's own little nuances, and each person has their own tase on what sounds good, so this is why I say experiment with it. Whatever works, works.

jonrose · Location: USA

Hypercardioid is a "tighter" heart-shaped pattern, with affords more side rejection. However, keep in mind that it does this at the expense of rear-rejection - you'll have a small response-lobe off the backside of the microphone when it's in hypercardioid mode, so just watch out for what's directly behind it when using this position.

Best... -Jon

Don Brisco · Posted - Tue Jul 15, 2003 10:41 pm

I plotted all the theoretical polor-response & M-S curves years ago in a couple of DOS spreadsheets.

The null in a hypercardioid is 110 degrees. So this mike is great if you place it say above or below a source (above, if miking a voice, to reduce blasting) so that its null is pointing towards the interfering noise source. Obviously, with a small rear lobe (at 180 degrees) you should not point the rear of the mike directly at the interfering source. As I recall, the overall sound pickup directivity of a hypercardioid (assuming interference is coming from all points of a 3-D sphere)is significantly less than a cardioid, so it should be a good choice for recording someone in the middle of a crowded, noisy room.

To play around yourself in Excel, put 1 in cell A1 and 3 in cell B1. These numbers are known as the "A" (pressure/omni compontent)& "B" (Pressure gradient/bidirectional component) values and can be changed to simulate different types of mic as shown later.

Now from A3:A38 use Fill | Series and go from 0 to 350 in steps of 10
(you could use steps of 5 but the graph might get busy). (Note: in a circular graph 0 & 360 are the same position.)

Enter this formula in B3:

=ABS(1/($A$1+$B$1)*($A$1+($B$1*COS(PI()*($A3)/180))))

Copy this formula to B4:B38

Highlight B3:B38. Select Chart Wizard | Radar | First Radar graph type (without data points) | Next | Next | select Legend Tab | untick "Show Legend" | Next | Finish.

The graph looks congested because of the 36 category labels (0-350). I delete them by clicking on one of them to switch to all Category Labels selected and then press the Delete key. Finally resize
and reposition the graph with your mouse.

Directivity "A" "B"
Omni 1 0
Cardioid 1 1
Bidirectional 0 1
Hypercardioid 1 3
Supercardioid 3 5

Subcardioid patterns occur when "A" > "B" and "B" is greater than 0.

SteveG · Location: United Kingdom

I haven't tried this, but it looks like quite a neat way to plot the theoretical responses. Better than my drawings are, anyway!