Pros and cons directional mic vs parabola

Question

While searching through the bird song literature, I realized there are two schools for recording songs. Some people use a directional microphone and some people use a parabola.

I was wondering why to chose one over the other... and what sort of measurements can be done on the recordings made by each device.

• For example, I understand that a parabola acts like a high pass frequency filter before the recording is made, and that there is distortions happening if the bird is "too close" to the microphone. So is it still possible to perform accurate frequency measurements from a recording made with a parabola?
• Is it possible to calibrate a parabola and extract amplitude measurements form the recordings (provided I know the distance to the bird)?
• What about recording distance, can I get clean recordings over a long distance with a directional microphone?

Answer 1

On the Cornell Lab of Ornithology webpage, there is a well written overview about the pro and cons for shotgun vs parabola: https://www.macaulaylibrary.org/resources/audio-recording-gear/microphones/

I personally use shotgun microphone from Sennheiser to record duetting birds (range from 1000 Hz to 5000 Hz). Regarding the recording distance you can get a "clean recording"... Well, it depends how loud is the vocalizing animal, and how noisy is the surroundings (wind, other vocalizing species, anthropogenic noise), and of course the model of microphone you use (cheap or expensive, and its size)

I've never used parabola so I cannot tell much on it. But I would say that if you record animals that emit low frequency vocalisations, it would be better to use shotgun microphone.

Have a good day

Answer 2

I use directional ("shot gun", though I hate that term) mic's for lemur vocalizations (+ a windscreen over it). The Sennheiser ME67, which has pretty much become the gold standard in primatology at least for vocal communication studies. Pretty affordable (couple hundred $$) and high quality. Parabolic mic's tend to be very expensive too, and are obviously much larger than directional mic's, so hauling them through the rainforests where I work would be not fun.

But, parabolic mic's tend to give you "cleaner" recordings as they filter out background noise & amplify the target signal better. So your signal-to-noise ratio is typically better with parabolic. There is however a lot of variation between brands of both types of mic's of course. Parabolic mic's are also affected by movement a lot, so they're great if your animal is calling while staying still, but can be more difficult to use when the animal is moving because the parabola is so directional.

In terms of recording distance, this really depends on a lot of other factors as well e.g., vegetation density/habitat type, climactic conditions (wind, rain, temperature), how loud the animal is calling (and if it's a single individual or a group chorus), if they're moving while they call, ambient noise (e.g., are you near a river or road, is it during a dawn chorus), etc. The directional mic I use for lemur vocals did a good job recording calls considering that the lemur species I study are high-canopy specialists and we're in a rainforest, so lots of dense vegetation and vertical distance inherent in the system. I'd say anecdotally that calls under ~75m ended up being high-quality enough for me to use in my analyses.