Glenn Norberg

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Oct 6, 2020
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Hello all, PLEASE HELP! LOL. I am new to this whole thing, I am building a 4-dish parabolic mic array for outdoor use. I will be recording with a Zoom H6n recorder. I am looking for microphone suggestions/insights. It appears that many dishes use lavalier mics. As I am 3D printing my own parabolic array, I have the opportunity to use pencil type condenser mics, But as I am new to this, I really have no idea what I should be looking at.

I do not have alot of money for this project, and I found a pair of mics for about $100 US. I am looking at these: https://www.amazon.com/gp/product/B000CZ0RLU/ref=ppx_yo_dt_b_asin_title_o07_s00?ie=UTF8&psc=1

Would these be appropriate for my use? Or should I be looking at lavalier mics? I am hoping to stay in this same budget (About $200 US for 4 mics) The dishes will be connected via XLR cables to the Zoom recorder no more than 25' away. I am afraid that 10' is a bit close, so I purchased 25' cables.

Thank you so much!

I am not anywhere near adept at electronics - so homemade gear (mics, preamps etc) are not quite out of the question, but close. Off the shelf is preferred.
 
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Glenn Norberg

New member
Oct 6, 2020
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What are you trying to capture?
The goal is to have (more or less) 360 degree coverage with (400mm dia) dishes to magnify the sounds. My limited experience with a hand held dish (prototype #1 ) allowed me to catch (annoyingly so) amplified audio from a fairly wide angle, and focus the dish where I chose for accuracy. The reason for the 4 dishes is to help determine the direction of a sound source. Then we would turn the array to face one of the dishes, focusing at the source. I figured that we would put them on a rotatable turntable of sorts.

I know it sounds crazy, but we are investigating the Bigfoot phenomenon We have reason to suspect that they come in stealthily and out of sight to observe ppl. We want to (hopefully) detect them via sound (tree snaps, etc) as they come in. The array is so we know what direction the approach is, and then use a FLIR to catch video.

If you have suggestions as to how to better achieve this goal, I am all ears (pun intended). I only have 4 XLR inputs available to me, and want to both listen to, and watch (on the meter) for where sounds/spikes are coming from.
 
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Chris Hindle

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Apr 18, 2011
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Not if you "catch" what you're looking for......
I don't see the need for a directional mic, as the parabola is focused in the mic element.
(the wrong piece of gear at the right price is still the wrong piece of gear)
Chris.
 

Shaun Davidson

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Dec 5, 2018
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So - you're building out 4 parabolic dishes and pointing them in four directions. Are you going to be standing / sitting in the middle? Or will the array need motors to turn them?

I'd probably try an omni lavalier mic. (Sweetwater link.) I'd get one to start with for testing if it was me.

Also - have fun hunting Bigfoot :) I'm not a believer, though I did, long ago, go on an expedition where we found pretty convincing tracks. It was very enjoyable.
 

Glenn Norberg

New member
Oct 6, 2020
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57
Colorado, USA
So - you're building out 4 parabolic dishes and pointing them in four directions. Are you going to be standing / sitting in the middle? Or will the array need motors to turn them?

I'd probably try an omni lavalier mic. (Sweetwater link.) I'd get one to start with for testing if it was me.

Also - have fun hunting Bigfoot :) I'm not a believer, though I did, long ago, go on an expedition where we found pretty convincing tracks. It was very enjoyable.
As each dish will be only 400mm dia, and they will 'nest into each other (back to back) the kit should be only about 450mm(ish) wide. We will probably have the array set on a tripod of sorts, or maybe on top of a vehicle. We will listen by headphone and watch the recording meter on the recorder distant from the array or from inside the vehicle to ascertain the direction. Hopefully we will be able to adjust/rotate the dish with the 'hit' do dial it in. We ordered 4 omni lavs. The dish array(s) are in the final design stage now. If you want, check out our YouTube Channel - Modern Explorer.
 

Riley Casey

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Jan 12, 2011
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WDC in the USA
www.espsound.com
As each dish will be only 400mm dia, and they will 'nest into each other (back to back) the kit should be only about 450mm(ish) wide. We will probably have the array set on a tripod of sorts, or maybe on top of a vehicle. We will listen by headphone and watch the recording meter on the recorder distant from the array or from inside the vehicle to ascertain the direction. Hopefully we will be able to adjust/rotate the dish with the 'hit' do dial it in. We ordered 4 omni lavs. The dish array(s) are in the final design stage now. If you want, check out our YouTube Channel - Modern Explorer.
The difference in amplitude between something moving thru vegetation even 25 feet from the mic and the ambient background noise on the other mics will not be visible on an audio meter. It will barely be perceptible on headphones with diligent listening. Have you just rented some mics and gone out in the woods one night to try this out? I suspect your expectations are not well connected to the physics of your plan.
 

Glenn Norberg

New member
Oct 6, 2020
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57
Colorado, USA
The difference in amplitude between something moving thru vegetation even 25 feet from the mic and the ambient background noise on the other mics will not be visible on an audio meter. It will barely be perceptible on headphones with diligent listening. Have you just rented some mics and gone out in the woods one night to try this out? I suspect your expectations are not well connected to the physics of your plan.
Admittedly, This is an experiment, not really knowing what the results will be. I have not heard of anyone actually doing this. Hence, the budget. My experience with a single dish is that quite a bit is heard and quite difficult to discern differences. Although I only expect (or desire) a 'sudden tree break' or somesuch to be heard whether it shows up on the meter is to be seen. (Hopefully, it will)

Diligent listening is certainly the key.
 

Art Welter

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Jan 11, 2011
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Florida
My experience with a single dish is that quite a bit is heard and quite difficult to discern differences. Although I only expect (or desire) a 'sudden tree break' or somesuch to be heard whether it shows up on the meter is to be seen. (Hopefully, it will)
Glenn, you may have already read this, but if not, it explains why you still will have little chance of success, even if a creature smart enough to escape detection was also stupid enough to clumsily break branches, which would result in high frequency impulse noise:


"A Parabolic dish is much like the analogy of a telephoto camera lens, at greater distances, more magnification is offered, but with a narrower field of view. Polar angle is about 90 degrees at 500Hz, closing down proportional with frequency to only 4-5 degrees at 10KHz. You will need to point the dish within 2 degrees (10 feet at 100 yards) if you want to retain the high frequency response."


Basically, what you are hoping for is your elusive guest happens to make it's clumsy mistake within four cardinal points the size of a motorcycle at the distance of a football field. And even if that remote bit of luck were to occur, like identifying a single hand clap or hiccough from a moving person in a full football stadium stand, unless that noise happens to be louder than the background noise generated in the foreground and background, it may as well never happened.
 

Glenn Norberg

New member
Oct 6, 2020
11
1
3
57
Colorado, USA
Glenn, you may have already read this, but if not, it explains why you still will have little chance of success, even if a creature smart enough to escape detection was also stupid enough to clumsily break branches, which would result in high frequency impulse noise:


"A Parabolic dish is much like the analogy of a telephoto camera lens, at greater distances, more magnification is offered, but with a narrower field of view. Polar angle is about 90 degrees at 500Hz, closing down proportional with frequency to only 4-5 degrees at 10KHz. You will need to point the dish within 2 degrees (10 feet at 100 yards) if you want to retain the high frequency response."

Basically, what you are hoping for is your elusive guest happens to make it's clumsy mistake within four cardinal points the size of a motorcycle at the distance of a football field. And even if that remote bit of luck were to occur, like identifying a single hand clap or hiccough from a moving person in a full football stadium stand, unless that noise happens to be louder than the background noise generated in the foreground and background, it may as well never happened.
Admittedly, this is quite a longshot. Hence the small budget. 3d printing etc. But one that might bear fruit - those are the chances one takes with experiments. Mostly finding out what does not work.... But until one tries, one never knows. We will be recording and reviewing the recording(s) if something odd were to occur. That is all we hope, that we 'get lucky'.