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-   -   Shotgun Mic questions. (https://www.dvinfo.net/forum/all-things-audio/50490-shotgun-mic-questions.html)

Ian E. Pearson September 3rd, 2005 05:39 PM

Shotgun Mic questions.
 
What are the practical differences between a line gradient and a cardioid mic? I know its a difference in the way they pick up sound but what does that mean in the real world?

Also, I was just wondering if anyone had comments on the Rode NTG 2. Soundprofessionals.com is sold out of the Audio Technica AT 897 but recommends this mic as an alternative.

Glenn Chan September 3rd, 2005 06:11 PM

When I say shotgun, I really mean a microphone using the line-gradient design.

A shotgun is a lot more directional than a cardioid mic. It picks up less of the sound that hits the microphone from the sides/back. This is nice, as the problem with many recordings is that there's too much background noise.

When sounds strike a shotgun off-axis (not from the front), there is a lot of sound coloration / the frequency response is extremely uneven / it sounds weird or "off-mic".
There's about a 30 degree cone for shotguns where things sound fine/normal, but anything off-axis sounds off and lower in volume.
With cardioids, off-axis sounds drop in volume less compared to shotguns. They also have an even frequency response, and off-axis sounds tend to lose high frequencies. Far enough off-axis and things will sound "off-mic".

By off-mic I mean that it sounds like the microphone isn't pointed at the sound source. It's kind of a circular definition, so that's not exactly helpful.

Indoors, shotguns sound really weird. I think it's because the echoes and reverb strike the microphone off-axis (and shotguns have really bad off-axis coloration).
A clip that shows this really well is
http://www.dvfreelancer.com/media/be...ktavaRight.MPG
The Oktava is using the hypercardioid capsule. Hypercardioid is like cardioid except more... so more directionality/rejection, more loss of high frequencies in off-axis sounds.

More differences:
Cardioid microphones tend to have lower self-noise. I think.
Shotguns tend to pickup more wind and handling noise.

2- I'm curious as to the Rode NTG2 compared to the AT897. I haven't seen any clips comparing both mics.

Guy Bruner September 3rd, 2005 06:30 PM

The NTG-2 is a good alternative to the AT897.

Douglas Spotted Eagle September 3rd, 2005 06:37 PM

Quote:

Originally Posted by Guy Bruner
The NTG-2 is a good alternative to the AT897.

Having both, I'd say that that the NTG-2 is an alternative to the 897. NTG2 is a little hotter, but isn't as smooth sounding. 897 has a little bump at the top which can be challenging for close-in V/O work, but it's sweet at a longer distance. Where you'll really note the difference is if you use them both indoors where there is a reverberant/live room. The NTG-2 turns pretty muddy, while the 897 has a marginally useful sound.
(Using a shotgun in a medium sized indoor space will quickly show you the weak spots of the mic. Keep in mind the only time you'll really use a shotgun indoors is for V/O work)

Guy Bruner September 3rd, 2005 07:42 PM

Thanks for the confirmation, Spot.


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