Parabolic Sonic Ears? What Do You Use?

[Guest]

The feedback stopped, only after I unplugged the Bionic Ear device from the Sony recorder. Unfortunately, the knocks also stopped, and were also drowned out in the recording, by the feedback. It started feeding back when I took the recorder off the standby listening mode, and started recording. Usually, feedback is the result of a mic being too close to a signal frequency. It did not get along with the Sony recorder, while it was recording.. for some reason, even though they were a few ft apart. Not exactly sure why it happened that way, but it stunk having it happen on a quiet listening position, when we were starting to get some action.The 9V minidish device (Bionic Ear) used just with headphones, there was no problem. 

[Guest]

I found a Parabolic a complete pain in the rear to use.  Difficult to transport, near impossible to walk in the woods with, upkeep/maintenance issues, and seemed I NEVER had it pointed in the right direction when a noise happened.

 

I ditched the parabolic and just use a Zoom 4Hn in the field; it's mics are nearly as sensitive as a parabolic's are, it's omnidirectional, has great fidelity, and it's portable.

[Guest]

Similar to my findings.. after a few seasons of using a larger parabolic for this kind of audio research, out in the forest. I started out, making the dish setup for nature recording. It works very well, for recording something you don't want to disturb ,at a distance.. where the subjects are vocalizing from a fixed general area (frogs, insects, birds ect). The unknowns (if they even sound off) are way too unpredictable. To have a complete (omnidirectional ) 360 deg field of audio coverage, has been the best way to go.

[bipedalist]

^ Agreed, the external omnidirectional mics hidden well and used with a quality digital audio recorder is all that you would need unless you are studying a Sasquatch in his caddyshack or doing the rounds as a Fairway Ranger.  

[Airdale]

WRT audio feedback, screeching, it is caused when the mic picks up the amplified audio that it has already delivered to the amplifier/recorder, etc. Most common when PA systems are used and the mic is moved too close to the speaker. If you were listening to the audio signal through headphones I can't envision a scenario that would develop feedback unless the phones were literally hung around the mic. My best guess, which comes from servicing microprocessor based office equipment for a quarter century, is that one piece of equipment was interfering with another. Most everything electrical and or electronic for the last couple of decades has some kind of microprocessor chip, even things like toasters, and those chips generate rf (radio frequency) signals and can be affected by other rf signals. These signals are limited by the inverse square principal, meaning that a signal of a given strength at a given distance will be at only 10% of that strength when the distance is doubled. This type of interference is virtually impossible to predict, but is easily solved if discovered by simply separating any competing devices by, usually, a foot or two for most items until the problem stops.

 

An example from my work involved a PA (Physicians Assistant) at a local ob/gyn clinic getting intermittent but repeated white noise on the professional hand held mini-cassette dictation recorder she had purchased from my company. I visited the facility and asked her to show me the locations she typically used when dictating. She first sat down next to an ultra-sound machine where she often recorded while scanning patients, leaning over right by the machine. I had her make a test recording and the noise was evident so I had her move about 18 inches away and repeat the test and the noise vanished. She then took me to her office and leaned forward with elbows on her desk calendar and made another test recording in which a similar noise was evident. I noticed that the recorder was within about ten inches of her desk phone console which she revealed had been installed a couple of months earlier to replace an aging phone system (about the time when she began having more recording issues). I suggested she lean back in her desk chair and try recording and again, the noise disappeared. 

 

Only one of the devices need have a microprocessor. I had one case where a customer complaint involved the print head or carrier on their electronic daisy wheel typewriter would suddenly begin tracking back and forth from one end of the machine to the other. The problem was rectified by moving their quite old, non-microprocessor equipped tape transcriber a couple of feet away from the typewriter. The oscillator circuit in the transcriber was generating an rf signal that confused the typewriter's computer chip. A similar but reverse case occurred when a new electronic typewriter was placed next to one of the older transcribers, causing the transcribing machine to pickup one of the local AM radio stations and play it through the transcriptionist's headphones. Again, a small physical separation solved the problem.

 

Also, some individuals can hold a much higher static electricity charge than others, causing physical damage to sensitive electronics they touch. This is easily solved by rigging a grounding pad of some kind to the part of the equipment they touch, i.e. a dictation microphone in one case I handled, the keyboard of a printing desk calculator in another. In the field, touching the heel of the hand to a grounded metal object will also work (the heel has a much lower nerve density than the finger tips, so you won't feel the zap of the static discharge).

 

All of these things can be problematic, but can generally be sussed out with some basic trouble shooting once you know what to look for. Unfortunately, when I started in the business in '79, there was no book so techs pretty much figured it out on their own and shared the findings with others, not a speedy process until the internet became accessible to the general public in the mid-nineties. I suspect that these things are responsible for a great deal of the "weird" situations when using electronics in the field although harsh environmental conditions such as N.A.W.A.C. faces in "Area X" are also a major contender.

[SWWASAS]

I have a homemade parabolic with a 2 foot dish. Useful around camp or sitting on a ridge listening as long as you can drive there as the thing is hardly portable. It is sensitive enough to pick up a fluttering leaf at about 100 yards. I had it pointed at some vegetation about 100 yards away and a humming bird flew by. Scared the you know what out of me. The problem as has been mentioned is portability. I have missed enough vocalizations at this point that I now pack mount a H2 recorder, and have it on record every minute I am out in the field. But my last encounter happened as soon as I got out of my truck and I even missed that. That was the chest slapping or beating thing I reported previously. The recorder was not on yet because I was desperate to pee. Now it is on and running before I park. I would recommend you have some sort of recorder running most of the time you are in the field. If nothing happens just delete the file. But if something does, you will have an audio record. I think since it is not hand held the recorder is more passive and more acceptable to BF than a camera is.

[Bigtex]

I used to be obsessed with recording sound, just don't have the time to listen to it all anymore. However, I have spent many years researching the good, bad, ugly, and THE very best. IMO this is the very best, and ask anyone who studies bird sounds what they use in the field, or is #1 on their wish list. Very pricey stuff, but if ya got the buckaroos.......give yourself an early Xmas gift! Go to the web site below, and click on the Telinga link. They offer several different variations depending on your particular recording device. If you're still in a festive mood, go ahead and splurge on a nice used Sound Devices 702 Field Recorder to record those sounds on, the whole package shouldn't be more than (gulp) 5K:)

 

Parabolic BEST - Telinga Microphones, www.naturesongs.com, Twin Science Mic, Also EM23 PIP & EM23 PIP Series 2 (works in dish too, Sennheiser best) : Telinga Microphones, Pl. 129 Botarbo, S-748 96 Tobo, Sweden, 011-46-295-31001

Edited November 27, 2013 by Bigtex

[Guest]

The main reason I want mine is the things that go bump in the night at the trailer. I want directionality. I can hear stuff, but I can't hear it very good. I have a hearing aid thing and I want to figure out a dish to go with it, and a handle so it will handle properly. I'm thinking I will use some kind of tupperware bowl or something.

Edited November 28, 2013 by Wag

[stancourtney]

As a general rule most people are better off with a good recorder such as the Sony PCM-10 with its built-in omnidirectional microphones.  Most cheaply made parabolic mics are nothing but toys and at the worst distort any sounds they record.

 

And I agree with Bigtex if you want the best buy the Telinga Parabolic Microphone and pair it with the Sound Devices Field Recorder. I have used the Sound Devices since 2006 and it is unmatched as a field recorder. I use it with my Telinga and they can't be beat.

[Guest]

Hey Stan, you ever price those Telingas and Sound Devices F. R's??? Big bucks!! Too steep for my budget...But I owe pretty much everything I know about recording wildlife, to you. Thanks for the hours and most of all, sharing!

Edited December 3, 2013 by kearnsey64

[southernyahoo]

Does anyone use parabolic sonic ears? What kind do you use? Anyone know how to make a good one? This might be a good idea if you have a recorder also, not sure how to hook it up to one though.

 

 *removed link to video

 

 

I use these Sonic super ear mics because of their price and I was satisfied with their clarity and amplification. 

 

http://www.thehomesecuritysuperstore.com/listening-devices-sonic-super-ear-sound-amplifier-p=3749

 

 

 

They may introduce some white noise that higher grade mics don't, but for the amplification in conjunction with a parabolic dish they really reach out and grab distant and faint sounds and I've not detected any actual distortion. You can get the feedback screech if the volume is up too high and you let the headphones get too close to the mics.

 

I use two of the mics located near the focal point of the dish, arranged and wired so they provide a left and right signal which provides a stereo experience at the headphones with a better sense of direction left or right for the sound source when tracking movement. If you are standing behind the dish, the left mic feeds the right ear and the right mic feeds the left ear. This has to do with the way the sounds enter the dish from different directions and thus focus at opposite sides of the dish. This also widens the area of sensitivity out in front of the dish.

 

I mounted this set up on a tripod which swivels like a turret when I want to be hands free and I can also get mobile with it when I want to move with a sound source by lifting it off the tripod.

 

Here's a link for some of the gear my group uses.

 

http://www.texlaresearch.com/cameras.htm

Edited December 3, 2013 by chelefoot
removed link to video in quote

[GuyInIndiana]

While I'm sure the guy in the OP video means well, one basic flaw he's engineered into his *dish* is the flat back wall. A true parabolic dish, whether audio or radio capturing, needs to have a mathematically consistent flow and form to it. That flat back/bottom where the mic will be pointing back into might work, but not the way nature (physics) intended. Here's a PDF link to understand the very basics of how it *should* work.

 

http://www.downeastmicrowave.com/PDF/dishfp.PDF

 

 

The end result in any dish, whether satellite or audio, is that the microphone should be well centered and facing directly into the exact or near exact center of the dish... but that's only half the battle. In too far or out too far, and you lose an overall appreciable amount of the energy (radio or sound) that is coming into the dish and bouncing to the true center point (focal point) which in this case is the mic element underneath all that plastic and/or extra foam windscreen you might add to it. I've even heard of some people buildiing the mic mount on an adjustable slide mechanism, so that while you have the unit operating, you put a pair of headphones on, then pick an object to point at. Then they will slowly adjust the mic (pointing into the dish center) in closer until the audio begins to diminish, and then work it back out until it does the same. Then by slowly working it back in, you can find that sweet spot where you're getting maximum reflection of the sound waves into the microphone element.

 

I hope that helps.

Edited December 3, 2013 by GuyInIndiana

[LeafTalker]

Awesome setups, SY!

 

and good info, GII.

[Guest]

If anything you would think that something like that would scare off a sasquatch.

[chelefoot]

Sorry guys, I accidently edited Southernyahoo's link to the ear mics. I will get that fixed asap! My bad!

 

 

Edit to add:  Ok all fixed, Sorry about that!

Edited December 3, 2013 by chelefoot