Edit: I recently added an article on the physics of parabolic microphone gain: LINK.
When I was twelve I discovered astronomy and made my first optics purchase, a cheap, awful refracting telescope made by the K-mart subsidiary Focal. I knew I needed a more serious instrument, and soon became obsessed with something called the Dynascope RV-6 that was advertised in a full-page ad in every issue of Sky & Telescope magazine.
I subscribed to this magazine and every month I would thoughtfully leave the latest issue folded open to this page and helpfully place it where my parents would see it. The ad pictured above is from 1975; in 1979 the price had gone up to $279, which became my working definition of the amount of money separating me from true happiness.
My parents eventually agreed to buy it. Purchasing something via mail was an exciting rite that began with cutting along the dotted line of the little order form, and then grappling with the dreadful reality of “allow six to eight weeks for delivery.” To demand that anyone wait so long was an outrage.
The RV-6 was Newtonian reflector with a 6-inch primary mirror. When I first read that Newton’s invention used a parabolic mirror, I had no idea what that could mean. I procured texts on algebra and geometry from the library and found to my surprise that I could understand them with a little effort. The parabola was a curve captured by such a simple expression, yet it had a seemingly magical property in that parallel lines, or rays, falling perpendicular upon it would all be reflected to the same focus. I went parabolic and there was no going back, not in terms of astronomical telescopes, nor in fascination with the mathematics inherent in nature.
Curiously, I had long resisted the urge to invest in a parabolic dish for audio. I’d been studying the available options for years, but keeping them at arm’s length. The idea of carting around such a massive instrument was unappealing. But just when I thought I’d finalized on a recording rig, it was clear it wasn’t the best setup for me. But because a long shotgun microphone inside a blimp is already bulky, it was getting me accustomed to sizable gear. It was a gateway drug, I suppose.
The Sennheiser MKH-416 microphone is great, but I’ve struggled to get enough separation between the bird and all the ambient noise that I seem to attract. Unless we are travelling, I don’t get to regularly leave suburbia and go far afield where the world is less noisy. I’m lucky that there is a large park near my home with a variety of habitats and often some good birds, but it is also rather busy with people, even before sunrise. Extreme directionality in a microphone is needed here.
I went with the Wildtronics Pro Mono parabolic with the integrated low self-noise microphone. I use this with the Zoom F3 32-bit digital recorder, and they match up wonderfully. I needn’t worry about gain settings since the F3 has effectively unlimited dynamic range. I get a large signal from the F3 output jack such that I only need to use a cheap set of earbuds to hone in on unseen birds. Another reason I had been leery of parabolics in the past was because I didn’t want to be saddled with bulky, hot, sweaty, over-the-ear headphones, as every image of a parabolic-wielding recordist would suggest is necessary. It isn’t.
I initially had some doubts about this setup when I first took it out. I was using the Zoom to provide phantom power for the microphone and was burning through AA batteries so fast that I could watch the power indicator dropping in real time. Since Wildtronics also has an option to use a 9V battery, I tried that but it didn’t help. Then I realized that the Zoom must be configured via the setup menu for the specific type of AA being used. I was using NiMH but had the unit set for Lithium. Set that up correctly and the problem is solved. One pair of batteries now lasts me a few days.
With a carabiner and zip-tie the unit is easy to carry on my waist and fairly unobtrusive. I also went back to wearing the F3 on my person, using a binocular strap. Attaching it to the microphone is too heavy and uncomfortable with prolonged use. As for handling and cable noise, I avoid it by simply not moving. It is easier to be play statue than to continually have to brandish the microphone plus recorder as a unit during an hours-long outing.
Of course, it is a huge attention-getter, which is the only drawback for the introvert birder looking to remain inconspicuous. My shotgun, blimp, and windscreen setup fits into a bag that I attach to my waist, so I can take it anywhere without attracting everyone’s gaze until I’m actually using it. But this dish provokes all kinds of curiosity, and maybe some suspicion, from the moment I leave the house. I have to resist the urge to use it to record interesting birdsong in the neighborhood, as pointing it towards someone’s property will likely not go over well.
Now after a couple of months of daily use, I don’t know how I got along without it. It isn’t just that I’m making better recordings, with the target bird right up front and usually overwhelming other sounds. It is that I’m also covering way more ground, so to speak, in hearing distant birds that I’d never have known were there otherwise. As case in point, I picked up my first-of-year Sedge Wren in my local patch in mid-July only because of this microphone. It was in an inaccessible area and I’d never had known it was there otherwise. For all I know it has been there since May, and I’d still be unaware of it had I not pointed the dish that way.
With the 3.5mm output jack on the Wildtronics, I can patch the signal into my Android and get Merlin’s opinion on calls that it would never pick up with the phone’s native microphone.
It is as if you’ve been birding for decades without any optical instruments at all, and then you go out one day with your first pair of binoculars. The gift of being able to bring the distant up close is something to be no less thankful for with sound than it is with light.
And there is no need to wait eight weeks for delivery; mine arrived in a couple of days. The twelve-year-old self that still inhabits part of my soul finds this very satisfying.